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Changes between Version 101 and Version 102 of WKTRaster/SpecificationWorking03

Timestamp:: 06/13/11 14:00:30 (2 years ago)
Author:: pracine
Comment:: --

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: Unmodified
: Added
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WKTRaster/SpecificationWorking03

v101	v102
771	771	4) ST_Intersection(raster, raster, 'geometry') -> geometry -- default both raster to band # 1
772	772
773		----
774		== '''Objective FV.16 - Being able to quickly get raster statistics.''' ==
775
776		'''Add cached basic raster statistic to the base raster WKB format.
777
778		Statistics to be cached should include:
779
780		min/max[[BR]]
781		mean[[BR]]
782		standard deviation[[BR]]
783		histogram[[BR]]
784		build parameters of stats (sample rate, method used to determine # of bins in histogram?)[[BR]]
785
786		How are the statistics to be kept fresh? Automatically using some method to see how much of the raster has changed since the last stats calculation? Or let the user decide?
787
788		----
789
790		'''ST_SummaryStats(raster, nband) -> record'''[[BR]]
791		This is the core function that gets the summary statistics (# of values, mean, standard deviation, minimum value, maximum value) of a specified raster's band. It is this function that ST_Mean, ST_StdDev and ST_MinMax calls for their appropriate values.
792
793		1. ST_SummaryStats(rast raster, nband int, exclude_nodata_value boolean) -> record
794
795		returns one record of five columns (count, mean, stddev, min, max)
796
797		nband: index of band
798
799		exclude_nodata_value: if FALSE, nodata values in band are included in the stats. if TRUE, nodata values are not included
800
801		{{{
802		ST_SummaryStats(rast, 1, FALSE)
803		}}}
804
805		2. ST_SummaryStats(rast raster, nband int) -> record
806
807		assumes exclude_nodata_value = TRUE
808
809		{{{
810		ST_SummaryStats(rast, 2)
811		}}}
812
813		3. ST_SummaryStats(rast raster, exclude_nodata_value boolean) -> record
814
815		assumes nband = 1
816
817		{{{
818		ST_SummaryStats(rast, TRUE)
819		}}}
820
821		4. ST_SummaryStats(rast raster) -> record
822
823		assumes nband = 1 and exclude_nodata_value = TRUE
824
825		{{{
826		ST_SummaryStats(rast)
827		}}}
828
829		Due to the time it may take to do on-the-fly calculation of summary stats for large rasters (say 10000 x 10000), an alternative that sacrifices accuracy for speed is required. The following functions sample a percentage of the raster in a methodical randomized manner. The algorithm used for sampling is...
830
831		1. select the larger dimension of the width and height. compute the number of pixels to sample in each "row" of the larger dimension
832
833		2. pick pixels from each "row" of the larger dimension in an incremental rolling manner where each increment is randomly determined.
834
835		The set of ST_ApproxSummaryStats functions are:
836
837		1. ST_ApproxSummaryStats(rast raster, nband int, exclude_nodata_value boolean, sample_percent double precision) -> record
838
839		sample_percent: a value between 0 and 1 indicating the percentage of the raster band's pixels to consider
840
841		{{{
842		ST_ApproxSummaryStats(rast, 3, FALSE, 0.1)
843
844		ST_ApproxSummaryStats(rast, 1, TRUE, 0.5)
845		}}}
846
847		2. ST_ApproxSummaryStats(rast raster, nband int, sample_percent double precision) -> record
848
849		assumes that nband = 1
850
851		{{{
852		ST_ApproxSummaryStats(rast, 2 0.01)
853
854		ST_ApproxSummaryStats(rast, 4, 0.025)
855		}}}
856
857		3. ST_ApproxSummaryStats(rast raster, exclude_nodata_value boolean, sample_percent double precision) -> record
858
859		assumes that nband = 1
860
861		{{{
862		ST_ApproxSummaryStats(rast, FALSE, 0.01)
863
864		ST_ApproxSummaryStats(rast, TRUE, 0.025)
865		}}}
866
867		4. ST_ApproxSummaryStats(rast raster, sample_percent double precision) -> record
868
869		assumes that nband = 1 and exclude_nodata_value = TRUE
870
871		{{{
872		ST_ApproxSummaryStats(rast, 0.25)
873		}}}
874
875		5. ST_ApproxSummaryStats(rast raster) -> record
876
877		assumes that nband = 1, exclude_nodata_value = TRUE and sample_percent = 0.1
878
879		{{{
880		ST_ApproxSummaryStats(rast)
881		}}}
882
883		The situation arises where the summary statistics of a coverage table is required. As the coverage may be large (tens of gigabytes of memory or larger), the following functions are provided to permit an incremental computation of the summary statistics.
884
885		1. ST_SummaryStats(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean) -> record
886
887		rastertable: name of table with raster column
888
889		rastercolumn: name of column of data type raster
890
891		{{{
892		ST_SummaryStats('tmax_2010', 'rast', 1, FALSE)
893
894		ST_SummaryStats('precip_2011', 'rast', 1, TRUE)
895		}}}
896
897		2. ST_SummaryStats(rastertable text, rastercolumn text, nband int) -> record
898
899		exclude_nodata_value = TRUE
900
901		{{{
902		ST_SummaryStats('tmax_2010', 'rast', 1)
903		}}}
904
905		3. ST_SummaryStats(rastertable text, rastercolumn text, exclude_nodata_value boolean) -> record
906
907		nband = 1
908
909		{{{
910		ST_SummaryStats('precip_2011', 'rast', TRUE)
911		}}}
912
913		4. ST_SummaryStats(rastertable text, rastercolumn text) -> record
914
915		nband = 1 and exclude_nodata_value = TRUE
916
917		{{{
918		ST_SummaryStats('tmin_2009', 'rast')
919		}}}
920
921		Variations for ST_ApproxSummaryStats are:
922
923		1. ST_ApproxSummaryStats(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean, sample_percent double precision) -> record
924
925		{{{
926		ST_ApproxSummaryStats('tmax_2010', 'rast', 1, FALSE, 0.5)
927
928		ST_ApproxSummaryStats('precip_2011', 'rast', 1, TRUE, 0.2)
929		}}}
930
931		2. ST_ApproxSummaryStats(rastertable text, rastercolumn text, nband int, sample_percent double precision) -> record
932
933		exclude_nodata_value = TRUE
934
935		{{{
936		ST_ApproxSummaryStats('tmax_2010', 'rast', 1, 0.5)
937
938		ST_ApproxSummaryStats('precip_2011', 'rast', 1, 0.2)
939		}}}
940
941		3. ST_ApproxSummaryStats(rastertable text, rastercolumn text, exclude_nodata_value boolean, sample_percent double precision) -> record
942
943		nband = 1
944
945		{{{
946		ST_ApproxSummaryStats('tmax_2010', 'rast', FALSE, 0.5)
947
948		ST_ApproxSummaryStats('precip_2011', 'rast', TRUE, 0.2)
949		}}}
950
951		4. ST_ApproxSummaryStats(rastertable text, rastercolumn text, sample_percent double precision) -> record
952
953		nband = 1 and exclude_nodata_value = TRUE
954
955		{{{
956		ST_ApproxSummaryStats('tmax_2010', 'rast', 0.5)
957
958		ST_ApproxSummaryStats('precip_2011', 'rast', 0.2)
959		}}}
960
961		5. ST_ApproxSummaryStats(rastertable text, rastercolumn text) -> record
962
963		nband = 1, exclude_nodata_value = TRUE and sample_percent = 0.1
964
965		{{{
966		ST_ApproxSummaryStats('tmax_2010', 'rast')
967
968		ST_ApproxSummaryStats('precip_2011', 'rast')
969		}}}
970
971		The mean returned in the coverage functions (has rastertable and rastercolumn arguments) is the true mean of the raster tiles. The standard deviation returned is the standard deviation of all raster tiles.
972
973		----
974
975		'''ST_Count(raster, nband) -> bigint'''[[BR]]
976
977		This function calls ST_SummaryStats and only returns the count from that function.
978
979		1. ST_Count(rast raster, nband int, exclude_nodata_value boolean) -> bigint
980
981		returns the count as an integer
982
983		nband: index of band
984
985		exclude_nodata_value: if FALSE, nodata values in band are included in the stats. if TRUE, nodata values are not included
986
987		{{{
988		ST_Count(rast, 1, FALSE)
989		}}}
990
991		2. ST_Count(rast raster, nband int) -> bigint
992
993		assumes exclude_nodata_value = TRUE
994
995		{{{
996		ST_Count(rast, 2)
997		}}}
998
999		3. ST_Count(rast raster, exclude_nodata_value boolean) -> bigint
1000
1001		assumes nband = 1
1002
1003		{{{
1004		ST_Count(rast, TRUE)
1005		}}}
1006
1007		4. ST_Count(rast raster) -> bigint
1008
1009		assumes nband = 1 and exclude_nodata_value = TRUE
1010
1011		{{{
1012		ST_Count(rast)
1013		}}}
1014
1015		The set of ST_ApproxCount functions are:
1016
1017		1. ST_ApproxCount(rast raster, nband int, exclude_nodata_value boolean, sample_percent double precision) -> bigint
1018
1019		sample_percent: a value between 0 and 1 indicating the percentage of the raster band's pixels to consider
1020
1021		{{{
1022		ST_ApproxCount(rast, 3, FALSE, 0.1)
1023
1024		ST_ApproxCount(rast, 1, TRUE, 0.5)
1025		}}}
1026
1027		2. ST_ApproxCount(rast raster, nband int, sample_percent double precision) -> bigint
1028
1029		assumes that nband = 1
1030
1031		{{{
1032		ST_ApproxCount(rast, 2 0.01)
1033
1034		ST_ApproxCount(rast, 4, 0.025)
1035		}}}
1036
1037		3. ST_ApproxCount(rast raster, exclude_nodata_value boolean, sample_percent double precision) -> bigint
1038
1039		assumes that nband = 1
1040
1041		{{{
1042		ST_ApproxCount(rast, FALSE, 0.01)
1043
1044		ST_ApproxCount(rast, TRUE, 0.025)
1045		}}}
1046
1047		4. ST_ApproxCount(rast raster, sample_percent double precision) -> bigint
1048
1049		assumes that nband = 1 and exclude_nodata_value = TRUE
1050
1051		{{{
1052		ST_ApproxCount(rast, 0.25)
1053		}}}
1054
1055		5. ST_ApproxCount(rast raster) -> bigint
1056
1057		assumes that nband = 1, exclude_nodata_value = TRUE and sample_percent = 0.1
1058
1059		{{{
1060		ST_ApproxCount(rast)
1061		}}}
1062
1063		The following functions are provided for coverage tables.
1064
1065		1. ST_Count(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean) -> bigint
1066
1067		rastertable: name of table with raster column
1068
1069		rastercolumn: name of column of data type raster
1070
1071		{{{
1072		ST_Count('tmax_2010', 'rast', 1, FALSE)
1073
1074		ST_Count('precip_2011', 'rast', 1, TRUE)
1075		}}}
1076
1077		2. ST_Count(rastertable text, rastercolumn text, nband int) -> bigint
1078
1079		exclude_nodata_value = TRUE
1080
1081		{{{
1082		ST_Count('tmax_2010', 'rast', 1)
1083		}}}
1084
1085		3. ST_Count(rastertable text, rastercolumn text, exclude_nodata_value boolean) -> bigint
1086
1087		nband = 1
1088
1089		{{{
1090		ST_Count('precip_2011', 'rast', TRUE)
1091		}}}
1092
1093		4. ST_Count(rastertable text, rastercolumn text) -> bigint
1094
1095		nband = 1 and exclude_nodata_value = TRUE
1096
1097		{{{
1098		ST_Count('tmin_2009', 'rast')
1099		}}}
1100
1101		Variations for ST_ApproxCount are:
1102
1103		1. ST_ApproxCount(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean, sample_percent double precision) -> bigint
1104
1105		{{{
1106		ST_ApproxCount('tmax_2010', 'rast', 1, FALSE, 0.5)
1107
1108		ST_ApproxCount('precip_2011', 'rast', 1, TRUE, 0.2)
1109		}}}
1110
1111		2. ST_ApproxCount(rastertable text, rastercolumn text, nband int, sample_percent double precision) -> bigint
1112
1113		exclude_nodata_value = TRUE
1114
1115		{{{
1116		ST_ApproxCount('tmax_2010', 'rast', 1, 0.5)
1117
1118		ST_ApproxCount('precip_2011', 'rast', 1, 0.2)
1119		}}}
1120
1121		3. ST_ApproxCount(rastertable text, rastercolumn text, exclude_nodata_value boolean, sample_percent double precision) -> bigint
1122
1123		nband = 1
1124
1125		{{{
1126		ST_ApproxCount('tmax_2010', 'rast', FALSE, 0.5)
1127
1128		ST_ApproxCount('precip_2011', 'rast', TRUE, 0.2)
1129		}}}
1130
1131		4. ST_ApproxCount(rastertable text, rastercolumn text, sample_percent double precision) -> bigint
1132
1133		nband = 1 and exclude_nodata_value = TRUE
1134
1135		{{{
1136		ST_ApproxCount('tmax_2010', 'rast', 0.5)
1137
1138		ST_ApproxCount('precip_2011', 'rast', 0.2)
1139		}}}
1140
1141		5. ST_ApproxCount(rastertable text, rastercolumn text) -> bigint
1142
1143		nband = 1, exclude_nodata_value = TRUE and sample_percent = 0.1
1144
1145		{{{
1146		ST_ApproxCount('tmax_2010', 'rast')
1147
1148		ST_ApproxCount('precip_2011', 'rast')
1149		}}}
1150
1151		----
1152
1153		'''ST_Sum(raster, nband) -> double precision'''[[BR]]
1154
1155		This function calls ST_SummaryStats and only returns the sum from that function.
1156
1157		1. ST_Sum(rast raster, nband int, exclude_nodata_value boolean) -> double precision
1158
1159		returns the sum as an integer
1160
1161		nband: index of band
1162
1163		exclude_nodata_value: if FALSE, nodata values in band are included in the stats. if TRUE, nodata values are not included
1164
1165		{{{
1166		ST_Sum(rast, 1, FALSE)
1167		}}}
1168
1169		2. ST_Sum(rast raster, nband int) -> double precision
1170
1171		assumes exclude_nodata_value = TRUE
1172
1173		{{{
1174		ST_Sum(rast, 2)
1175		}}}
1176
1177		3. ST_Sum(rast raster, exclude_nodata_value boolean) -> double precision
1178
1179		assumes nband = 1
1180
1181		{{{
1182		ST_Sum(rast, TRUE)
1183		}}}
1184
1185		4. ST_Sum(rast raster) -> double precision
1186
1187		assumes nband = 1 and exclude_nodata_value = TRUE
1188
1189		{{{
1190		ST_Sum(rast)
1191		}}}
1192
1193		The set of ST_ApproxSum functions are:
1194
1195		1. ST_ApproxSum(rast raster, nband int, exclude_nodata_value boolean, sample_percent double precision) -> double precision
1196
1197		sample_percent: a value between 0 and 1 indicating the percentage of the raster band's pixels to consider
1198
1199		{{{
1200		ST_ApproxSum(rast, 3, FALSE, 0.1)
1201
1202		ST_ApproxSum(rast, 1, TRUE, 0.5)
1203		}}}
1204
1205		2. ST_ApproxSum(rast raster, nband int, sample_percent double precision) -> double precision
1206
1207		assumes that nband = 1
1208
1209		{{{
1210		ST_ApproxSum(rast, 2 0.01)
1211
1212		ST_ApproxSum(rast, 4, 0.025)
1213		}}}
1214
1215		3. ST_ApproxSum(rast raster, exclude_nodata_value boolean, sample_percent double precision) -> double precision
1216
1217		assumes that nband = 1
1218
1219		{{{
1220		ST_ApproxSum(rast, FALSE, 0.01)
1221
1222		ST_ApproxSum(rast, TRUE, 0.025)
1223		}}}
1224
1225		4. ST_ApproxSum(rast raster, sample_percent double precision) -> double precision
1226
1227		assumes that nband = 1 and exclude_nodata_value = TRUE
1228
1229		{{{
1230		ST_ApproxSum(rast, 0.25)
1231		}}}
1232
1233		5. ST_ApproxSum(rast raster) -> double precision
1234
1235		assumes that nband = 1, exclude_nodata_value = TRUE and sample_percent = 0.1
1236
1237		{{{
1238		ST_ApproxSum(rast)
1239		}}}
1240
1241		The following functions are provided for coverage tables.
1242
1243		1. ST_Sum(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean) -> double precision
1244
1245		rastertable: name of table with raster column
1246
1247		rastercolumn: name of column of data type raster
1248
1249		{{{
1250		ST_Sum('tmax_2010', 'rast', 1, FALSE)
1251
1252		ST_Sum('precip_2011', 'rast', 1, TRUE)
1253		}}}
1254
1255		2. ST_Sum(rastertable text, rastercolumn text, nband int) -> double precision
1256
1257		exclude_nodata_value = TRUE
1258
1259		{{{
1260		ST_Sum('tmax_2010', 'rast', 1)
1261		}}}
1262
1263		3. ST_Sum(rastertable text, rastercolumn text, exclude_nodata_value boolean) -> double precision
1264
1265		nband = 1
1266
1267		{{{
1268		ST_Sum('precip_2011', 'rast', TRUE)
1269		}}}
1270
1271		4. ST_Sum(rastertable text, rastercolumn text) -> double precision
1272
1273		nband = 1 and exclude_nodata_value = TRUE
1274
1275		{{{
1276		ST_Sum('tmin_2009', 'rast')
1277		}}}
1278
1279		Variations for ST_ApproxSum are:
1280
1281		1. ST_ApproxSum(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean, sample_percent double precision) -> double precision
1282
1283		{{{
1284		ST_ApproxSum('tmax_2010', 'rast', 1, FALSE, 0.5)
1285
1286		ST_ApproxSum('precip_2011', 'rast', 1, TRUE, 0.2)
1287		}}}
1288
1289		2. ST_ApproxSum(rastertable text, rastercolumn text, nband int, sample_percent double precision) -> double precision
1290
1291		exclude_nodata_value = TRUE
1292
1293		{{{
1294		ST_ApproxSum('tmax_2010', 'rast', 1, 0.5)
1295
1296		ST_ApproxSum('precip_2011', 'rast', 1, 0.2)
1297		}}}
1298
1299		3. ST_ApproxSum(rastertable text, rastercolumn text, exclude_nodata_value boolean, sample_percent double precision) -> double precision
1300
1301		nband = 1
1302
1303		{{{
1304		ST_ApproxSum('tmax_2010', 'rast', FALSE, 0.5)
1305
1306		ST_ApproxSum('precip_2011', 'rast', TRUE, 0.2)
1307		}}}
1308
1309		4. ST_ApproxSum(rastertable text, rastercolumn text, sample_percent double precision) -> double precision
1310
1311		nband = 1 and exclude_nodata_value = TRUE
1312
1313		{{{
1314		ST_ApproxSum('tmax_2010', 'rast', 0.5)
1315
1316		ST_ApproxSum('precip_2011', 'rast', 0.2)
1317		}}}
1318
1319		5. ST_ApproxSum(rastertable text, rastercolumn text) -> double precision
1320
1321		nband = 1, exclude_nodata_value = TRUE and sample_percent = 0.1
1322
1323		{{{
1324		ST_ApproxSum('tmax_2010', 'rast')
1325
1326		ST_ApproxSum('precip_2011', 'rast')
1327		}}}
1328
1329		----
1330
1331		'''ST_Mean(raster, nband) -> double precision'''[[BR]]
1332		This function calls ST_SummaryStats and only returns the mean from that function.
1333
1334		1. ST_Mean(rast raster, nband int, exclude_nodata_value boolean) -> double precision
1335
1336		returns the mean as a double precision
1337
1338		nband: index of band
1339
1340		exclude_nodata_value: if FALSE, nodata values in band are included. if TRUE, nodata values are not included.
1341
1342		{{{
1343		ST_Mean(rast, 1, FALSE)
1344		}}}
1345
1346		2. ST_Mean(rast raster, nband int) -> double precision
1347
1348		assumes exclude_nodata_value = TRUE
1349
1350		{{{
1351		ST_Mean(rast, 2)
1352		}}}
1353
1354		3. ST_Mean(rast raster, exclude_nodata_value boolean) -> double precision
1355
1356		assumes nband = 1
1357
1358		{{{
1359		ST_Mean(rast, TRUE)
1360		}}}
1361
1362		4. ST_Mean(rast raster) -> double precision
1363
1364		assumes nband = 1 and exclude_nodata_value = TRUE
1365
1366		{{{
1367		ST_Mean(rast)
1368		}}}
1369
1370		The set of ST_ApproxMean functions are:
1371
1372		1. ST_ApproxMean(rast raster, nband int, exclude_nodata_value boolean, sample_percent double precision) -> double precision
1373
1374		sample_percent: a value between 0 and 1 indicating the percentage of the raster band's pixels to consider
1375
1376		{{{
1377		ST_ApproxMean(rast, 3, FALSE, 0.1)
1378
1379		ST_ApproxMean(rast, 1, TRUE, 0.5)
1380		}}}
1381
1382		2. ST_ApproxMean(rast raster, nband int, sample_percent double precision) -> double precision
1383
1384		assumes that nband = 1
1385
1386		{{{
1387		ST_ApproxMean(rast, 2 0.01)
1388
1389		ST_ApproxMean(rast, 4, 0.025)
1390		}}}
1391
1392		3. ST_ApproxMean(rast raster, exclude_nodata_value boolean, sample_percent double precision) -> double precision
1393
1394		assumes that nband = 1
1395
1396		{{{
1397		ST_ApproxMean(rast, FALSE, 0.01)
1398
1399		ST_ApproxMean(rast, TRUE, 0.025)
1400		}}}
1401
1402		4. ST_ApproxMean(rast raster, sample_percent double precision) -> double precision
1403
1404		assumes that nband = 1 and exclude_nodata_value = TRUE
1405
1406		{{{
1407		ST_ApproxMean(rast, 0.25)
1408		}}}
1409
1410		5. ST_ApproxMean(rast raster) -> double precision
1411
1412		assumes that nband = 1, exclude_nodata_value = TRUE and sample_percent = 0.1
1413
1414		{{{
1415		ST_ApproxMean(rast)
1416		}}}
1417
1418		The following functions are provided for coverage tables.
1419
1420		1. ST_Mean(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean) -> double precision
1421
1422		rastertable: name of table with raster column
1423
1424		rastercolumn: name of column of data type raster
1425
1426		{{{
1427		ST_Mean('tmax_2010', 'rast', 1, FALSE)
1428
1429		ST_Mean('precip_2011', 'rast', 1, TRUE)
1430		}}}
1431
1432		2. ST_Mean(rastertable text, rastercolumn text, nband int) -> double precision
1433
1434		exclude_nodata_value = TRUE
1435
1436		{{{
1437		ST_Mean('tmax_2010', 'rast', 1)
1438		}}}
1439
1440		3. ST_Mean(rastertable text, rastercolumn text, exclude_nodata_value boolean) -> double precision
1441
1442		nband = 1
1443
1444		{{{
1445		ST_Mean('precip_2011', 'rast', TRUE)
1446		}}}
1447
1448		4. ST_Mean(rastertable text, rastercolumn text) -> double precision
1449
1450		nband = 1 and exclude_nodata_value = TRUE
1451
1452		{{{
1453		ST_Mean('tmin_2009', 'rast')
1454		}}}
1455
1456		Variations for ST_ApproxMean are:
1457
1458		1. ST_ApproxMean(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean, sample_percent double precision) -> double precision
1459
1460		{{{
1461		ST_ApproxMean('tmax_2010', 'rast', 1, FALSE, 0.5)
1462
1463		ST_ApproxMean('precip_2011', 'rast', 1, TRUE, 0.2)
1464		}}}
1465
1466		2. ST_ApproxMean(rastertable text, rastercolumn text, nband int, sample_percent double precision) -> double precision
1467
1468		exclude_nodata_value = TRUE
1469
1470		{{{
1471		ST_ApproxMean('tmax_2010', 'rast', 1, 0.5)
1472
1473		ST_ApproxMean('precip_2011', 'rast', 1, 0.2)
1474		}}}
1475
1476		3. ST_ApproxMean(rastertable text, rastercolumn text, exclude_nodata_value boolean, sample_percent double precision) -> double precision
1477
1478		nband = 1
1479
1480		{{{
1481		ST_ApproxMean('tmax_2010', 'rast', FALSE, 0.5)
1482
1483		ST_ApproxMean('precip_2011', 'rast', TRUE, 0.2)
1484		}}}
1485
1486		4. ST_ApproxMean(rastertable text, rastercolumn text, sample_percent double precision) -> double precision
1487
1488		nband = 1 and exclude_nodata_value = TRUE
1489
1490		{{{
1491		ST_ApproxMean('tmax_2010', 'rast', 0.5)
1492
1493		ST_ApproxMean('precip_2011', 'rast', 0.2)
1494		}}}
1495
1496		5. ST_ApproxMean(rastertable text, rastercolumn text) -> double precision
1497
1498		nband = 1, exclude_nodata_value = TRUE and sample_percent = 0.1
1499
1500		{{{
1501		ST_ApproxMean('tmax_2010', 'rast')
1502
1503		ST_ApproxMean('precip_2011', 'rast')
1504		}}}
1505
1506		The mean returned in the coverage functions (has rastertable and rastercolumn arguments) is the true mean of the raster tiles.
1507
1508		----
1509
1510		'''ST_StdDev(raster, nband) -> double precision'''[[BR]]
1511		This function calls ST_SummaryStats and only returns the standard deviation from that function.
1512
1513		1. ST_StdDev(rast raster, nband int, exclude_nodata_value boolean) -> double precision
1514
1515		returns the standard deviation as a double precision
1516
1517		nband: index of band
1518
1519		exclude_nodata_value: if FALSE, nodata values in band are included. if TRUE, nodata values are not included.
1520
1521		{{{
1522		ST_StdDev(rast, 1, FALSE)
1523		}}}
1524
1525		2. ST_StdDev(rast raster, nband int) -> double precision
1526
1527		assumes exclude_nodata_value = TRUE
1528
1529		{{{
1530		ST_StdDev(rast, 2)
1531		}}}
1532
1533		3. ST_StdDev(rast raster, exclude_nodata_value boolean) -> double precision
1534
1535		assumes nband = 1
1536
1537		{{{
1538		ST_StdDev(rast, TRUE)
1539		}}}
1540
1541		4. ST_StdDev(rast raster) -> double precision
1542
1543		assumes nband = 1 and exclude_nodata_value = TRUE
1544
1545		{{{
1546		ST_StdDev(rast)
1547		}}}
1548
1549		The set of ST_ApproxStdDev functions are:
1550
1551		1. ST_ApproxStdDev(rast raster, nband int, exclude_nodata_value boolean, sample_percent double precision) -> double precision
1552
1553		sample_percent: a value between 0 and 1 indicating the percentage of the raster band's pixels to consider
1554
1555		{{{
1556		ST_ApproxStdDev(rast, 3, FALSE, 0.1)
1557
1558		ST_ApproxStdDev(rast, 1, TRUE, 0.5)
1559		}}}
1560
1561		2. ST_ApproxStdDev(rast raster, nband int, sample_percent double precision) -> double precision
1562
1563		assumes that nband = 1
1564
1565		{{{
1566		ST_ApproxStdDev(rast, 2 0.01)
1567
1568		ST_ApproxStdDev(rast, 4, 0.025)
1569		}}}
1570
1571		3. ST_ApproxStdDev(rast raster, exclude_nodata_value boolean, sample_percent double precision) -> double precision
1572
1573		assumes that nband = 1
1574
1575		{{{
1576		ST_ApproxStdDev(rast, FALSE, 0.01)
1577
1578		ST_ApproxStdDev(rast, TRUE, 0.025)
1579		}}}
1580
1581		4. ST_ApproxStdDev(rast raster, sample_percent double precision) -> double precision
1582
1583		assumes that nband = 1 and exclude_nodata_value = TRUE
1584
1585		{{{
1586		ST_ApproxStdDev(rast, 0.25)
1587		}}}
1588
1589		5. ST_ApproxStdDev(rast raster) -> double precision
1590
1591		assumes that nband = 1, exclude_nodata_value = TRUE and sample_percent = 0.1
1592
1593		{{{
1594		ST_ApproxStdDev(rast)
1595		}}}
1596
1597		The following functions are provided for coverage tables.
1598
1599		1. ST_StdDev(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean) -> double precision
1600
1601		rastertable: name of table with raster column
1602
1603		rastercolumn: name of column of data type raster
1604
1605		{{{
1606		ST_StdDev('tmax_2010', 'rast', 1, FALSE)
1607
1608		ST_StdDev('precip_2011', 'rast', 1, TRUE)
1609		}}}
1610
1611		2. ST_StdDev(rastertable text, rastercolumn text, nband int) -> double precision
1612
1613		exclude_nodata_value = TRUE
1614
1615		{{{
1616		ST_StdDev('tmax_2010', 'rast', 1)
1617		}}}
1618
1619		3. ST_StdDev(rastertable text, rastercolumn text, exclude_nodata_value boolean) -> double precision
1620
1621		nband = 1
1622
1623		{{{
1624		ST_StdDev('precip_2011', 'rast', TRUE)
1625		}}}
1626
1627		4. ST_StdDev(rastertable text, rastercolumn text) -> double precision
1628
1629		nband = 1 and exclude_nodata_value = TRUE
1630
1631		{{{
1632		ST_StdDev('tmin_2009', 'rast')
1633		}}}
1634
1635		Variations for ST_ApproxStdDev are:
1636
1637		1. ST_ApproxStdDev(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean, sample_percent double precision) -> double precision
1638
1639		{{{
1640		ST_ApproxStdDev('tmax_2010', 'rast', 1, FALSE, 0.5)
1641
1642		ST_ApproxStdDev('precip_2011', 'rast', 1, TRUE, 0.2)
1643		}}}
1644
1645		2. ST_ApproxStdDev(rastertable text, rastercolumn text, nband int, sample_percent double precision) -> double precision
1646
1647		exclude_nodata_value = TRUE
1648
1649		{{{
1650		ST_ApproxStdDev('tmax_2010', 'rast', 1, 0.5)
1651
1652		ST_ApproxStdDev('precip_2011', 'rast', 1, 0.2)
1653		}}}
1654
1655		3. ST_ApproxStdDev(rastertable text, rastercolumn text, exclude_nodata_value boolean, sample_percent double precision) -> double precision
1656
1657		nband = 1
1658
1659		{{{
1660		ST_ApproxStdDev('tmax_2010', 'rast', FALSE, 0.5)
1661
1662		ST_ApproxStdDev('precip_2011', 'rast', TRUE, 0.2)
1663		}}}
1664
1665		4. ST_ApproxStdDev(rastertable text, rastercolumn text, sample_percent double precision) -> double precision
1666
1667		nband = 1 and exclude_nodata_value = TRUE
1668
1669		{{{
1670		ST_ApproxStdDev('tmax_2010', 'rast', 0.5)
1671
1672		ST_ApproxStdDev('precip_2011', 'rast', 0.2)
1673		}}}
1674
1675		5. ST_ApproxStdDev(rastertable text, rastercolumn text) -> double precision
1676
1677		nband = 1, exclude_nodata_value = TRUE and sample_percent = 0.1
1678
1679		{{{
1680		ST_ApproxStdDev('tmax_2010', 'rast')
1681
1682		ST_ApproxStdDev('precip_2011', 'rast')
1683		}}}
1684
1685		The standard deviation returned in the coverage functions (has rastertable and rastercolumn arguments) is the standard deviation of all raster tiles.
1686
1687		----
1688
1689		'''ST_MinMax(raster, nband) -> record'''[[BR]]
1690		This function calls ST_SummaryStats and only returns the min and max values from that function.
1691
1692		1. ST_MinMax(rast raster, nband int, exclude_nodata_value boolean) -> record
1693
1694		returns the record (min double precision, max double precision)
1695
1696		nband: index of band
1697
1698		exclude_nodata_value: if FALSE, nodata values in band are included. if TRUE, nodata values are not included.
1699
1700		{{{
1701		ST_MinMax(rast, 1, FALSE)
1702		}}}
1703
1704		2. ST_MinMax(rast raster, nband int) -> record
1705
1706		assumes exclude_nodata_value = TRUE
1707
1708		{{{
1709		ST_MinMax(rast, 2)
1710		}}}
1711
1712		3. ST_MinMax(rast raster, exclude_nodata_value boolean) -> record
1713
1714		assumes nband = 1
1715
1716		{{{
1717		ST_MinMax(rast, TRUE)
1718		}}}
1719
1720		4. ST_MinMax(rast raster) -> record
1721
1722		assumes nband = 1 and exclude_nodata_value = TRUE
1723
1724		{{{
1725		ST_MinMax(rast)
1726		}}}
1727
1728		The set of ST_ApproxMinMax functions are:
1729
1730		1. ST_ApproxMinMax(rast raster, nband int, exclude_nodata_value boolean, sample_percent record) -> record
1731
1732		sample_percent: a value between 0 and 1 indicating the percentage of the raster band's pixels to consider
1733
1734		{{{
1735		ST_ApproxMinMax(rast, 3, FALSE, 0.1)
1736
1737		ST_ApproxMinMax(rast, 1, TRUE, 0.5)
1738		}}}
1739
1740		2. ST_ApproxMinMax(rast raster, nband int, sample_percent double precision) -> record
1741
1742		assumes that nband = 1
1743
1744		{{{
1745		ST_ApproxMinMax(rast, 2 0.01)
1746
1747		ST_ApproxMinMax(rast, 4, 0.025)
1748		}}}
1749
1750		3. ST_ApproxMinMax(rast raster, exclude_nodata_value boolean, sample_percent double precision) -> record
1751
1752		assumes that nband = 1
1753
1754		{{{
1755		ST_ApproxMinMax(rast, FALSE, 0.01)
1756
1757		ST_ApproxMinMax(rast, TRUE, 0.025)
1758		}}}
1759
1760		4. ST_ApproxMinMax(rast raster, sample_percent double precision) -> record
1761
1762		assumes that nband = 1 and exclude_nodata_value = TRUE
1763
1764		{{{
1765		ST_ApproxMinMax(rast, 0.25)
1766		}}}
1767
1768		5. ST_ApproxMinMax(rast raster) -> record
1769
1770		assumes that nband = 1, exclude_nodata_value = TRUE and sample_percent = 0.1
1771
1772		{{{
1773		ST_ApproxMinMax(rast)
1774		}}}
1775
1776		The following functions are provided for coverage tables.
1777
1778		1. ST_MinMax(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean) -> record
1779
1780		rastertable: name of table with raster column
1781
1782		rastercolumn: name of column of data type raster
1783
1784		{{{
1785		ST_MinMax('tmax_2010', 'rast', 1, FALSE)
1786
1787		ST_MinMax('precip_2011', 'rast', 1, TRUE)
1788		}}}
1789
1790		2. ST_MinMax(rastertable text, rastercolumn text, nband int) -> record
1791
1792		exclude_nodata_value = TRUE
1793
1794		{{{
1795		ST_MinMax('tmax_2010', 'rast', 1)
1796		}}}
1797
1798		3. ST_MinMax(rastertable text, rastercolumn text, exclude_nodata_value boolean) -> record
1799
1800		nband = 1
1801
1802		{{{
1803		ST_MinMax('precip_2011', 'rast', TRUE)
1804		}}}
1805
1806		4. ST_MinMax(rastertable text, rastercolumn text) -> record
1807
1808		nband = 1 and exclude_nodata_value = TRUE
1809
1810		{{{
1811		ST_MinMax('tmin_2009', 'rast')
1812		}}}
1813
1814		Variations for ST_ApproxMinMax are:
1815
1816		1. ST_ApproxMinMax(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean, sample_percent double precision) -> record
1817
1818		{{{
1819		ST_ApproxMinMax('tmax_2010', 'rast', 1, FALSE, 0.5)
1820
1821		ST_ApproxMinMax('precip_2011', 'rast', 1, TRUE, 0.2)
1822		}}}
1823
1824		2. ST_ApproxMinMax(rastertable text, rastercolumn text, nband int, sample_percent double precision) -> record
1825
1826		exclude_nodata_value = TRUE
1827
1828		{{{
1829		ST_ApproxMinMax('tmax_2010', 'rast', 1, 0.5)
1830
1831		ST_ApproxMinMax('precip_2011', 'rast', 1, 0.2)
1832		}}}
1833
1834		3. ST_ApproxMinMax(rastertable text, rastercolumn text, exclude_nodata_value boolean, sample_percent double precision) -> record
1835
1836		nband = 1
1837
1838		{{{
1839		ST_ApproxMinMax('tmax_2010', 'rast', FALSE, 0.5)
1840
1841		ST_ApproxMinMax('precip_2011', 'rast', TRUE, 0.2)
1842		}}}
1843
1844		4. ST_ApproxMinMax(rastertable text, rastercolumn text, sample_percent double precision) -> record
1845
1846		nband = 1 and exclude_nodata_value = TRUE
1847
1848		{{{
1849		ST_ApproxMinMax('tmax_2010', 'rast', 0.5)
1850
1851		ST_ApproxMinMax('precip_2011', 'rast', 0.2)
1852		}}}
1853
1854		5. ST_ApproxMinMax(rastertable text, rastercolumn text) -> record
1855
1856		nband = 1, exclude_nodata_value = TRUE and sample_percent = 0.1
1857
1858		{{{
1859		ST_ApproxMinMax('tmax_2010', 'rast')
1860
1861		ST_ApproxMinMax('precip_2011', 'rast')
1862		}}}
1863
1864		----
1865
1866		'''ST_Histogram(raster, nband) -> set of records'''[[BR]]
1867		ST_Histogram and ST_ApproxHistogram provide methods to determine a raster's data distribution.
1868
1869		The return of ST_Histogram and ST_ApproxHistogram is a set of records where each record is (min, max, count, percent).
1870
1871		ST_Histogram has the following variations.
1872
1873		1. ST_Histogram(rast raster, nband int, exclude_nodata_value boolean, bins int, width double precision[], right boolean) -> set of records
1874
1875		returns set of records of four columns (min, max, count, percent)
1876
1877		nband: index of band to process on
1878
1879		exclude_nodata_value: if FALSE, nodata values in band are included. if TRUE, nodata values are not included.
1880
1881		bins: the number of categories/bins to have in the histogram. If NULL or value less than one, the number of categories will be auto-computed using Sturges' formula if the number of values >= 30 or Square-root choice if number of values < 30.
1882
1883		http://en.wikipedia.org/wiki/Histogram#Mathematical_definition
1884
1885		width: an array indicating the width of each category/bin. If the number of bins is greater than the number of widths, the widths are repeated. Example: 9 bins, widths are [a, b, c] will have the output be [a, b, c, a, b, c, a, b, c].
1886
1887		right: compute the histogram from the right rather than from the left (default). This changes the criteria for evaluating a value x from [a, b) to (a, b].
1888
1889		{{{
1890		ST_Histogram(rast, 2, FALSE, NULL, NULL, FALSE)
1891
1892		ST_Histogram(rast, 1, TRUE, 100, NULL, FALSE)
1893
1894		ST_Histogram(rast, 2, FALSE, NULL, ARRAY[100, 50], FALSE)
1895
1896		ST_Histogram(rast, 2, FALSE, 9, ARRAY[1000], TRUE)
1897
1898		ST_Histogram(rast, 2, FALSE, 20, ARRAY[100, 200, 300], TRUE)
1899		}}}
1900
1901		2. ST_Histogram(rast raster, nband int, exclude_nodata_value boolean, bins int, right boolean) -> set of records
1902
1903		parameter "width" is not specified thus resulting in all bins having the same widths
1904
1905		{{{
1906		ST_Histogram(rast, 2, FALSE, 5, FALSE)
1907		}}}
1908
1909		3. ST_Histogram(rast raster, nband int, exclude_nodata_value boolean, bins int) -> set of records
1910
1911		the parameter "right" is removed and assumed to be FALSE
1912
1913		{{{
1914		ST_Histogram(rast, 2, FALSE, 5)
1915		}}}
1916
1917		4. ST_Histogram(rast raster, nband int, exclude_nodata_value boolean) -> set of records
1918
1919		the parameter "bins" is removed and set to NULL. The function will compute the number of bins to use
1920
1921		5. ST_Histogram(rast raster, nband int) -> set of records
1922
1923		exclude_nodata_value is assumed to be TRUE
1924
1925		6. ST_Histogram(rast raster) -> set of records
1926
1927		assumes that nband is 1.
1928
1929		7. ST_Histogram(rast raster, nband int, bins int, width double precision[], right boolean) -> set of records
1930
1931		exclude_nodata_value is assumed to be TRUE
1932
1933		8. ST_Histogram(rast raster, nband int, bins int, right boolean) -> set of records
1934
1935		all bins will have equal widths
1936
1937		9. ST_Histogram(rast raster, nband int, bins int) -> set of records
1938
1939		right is assumed to be FALSE
1940
1941		ST_ApproxHistogram should have the following variations.
1942
1943		1. ST_ApproxHistogram(rast raster, nband int, exclude_nodata_value boolean, sample_percent double precision, bins int, width double precision[], right boolean) -> set of record
1944
1945		sample_percent: a value between 0 and 1 indicating the percentage of the raster band's pixels to consider when generating the histogram.
1946
1947		{{{
1948		ST_Histogram(rast, 2, FALSE, 0.1, NULL, NULL, FALSE)
1949
1950		ST_Histogram(rast, 1, TRUE, 1, 100, NULL, FALSE)
1951
1952		ST_Histogram(rast, 2, FALSE, 0.2, NULL, ARRAY[100, 50], FALSE)
1953
1954		ST_Histogram(rast, 2, FALSE, 0.25, 9, ARRAY[1000], TRUE)
1955
1956		ST_Histogram(rast, 2, FALSE, 0.05, 20, ARRAY[100, 200, 300], TRUE)
1957		}}}
1958
1959		2. ST_ApproxHistogram(rast raster, nband int, exclude_nodata_value boolean, sample_percent double precision, bins int, right boolean) -> set of records
1960
1961		parameter "width" is not specified thus resulting in all bins having the same widths
1962
1963		3. ST_ApproxHistogram(rast raster, nband int, exclude_nodata_value boolean, sample_percent double precision, bins int) -> set of records
1964
1965		the parameter "right" is removed and assumed to be FALSE
1966
1967		{{{
1968		ST_ApproxHistogram(rast, 2, FALSE, 5)
1969		}}}
1970
1971		4. ST_ApproxHistogram(rast raster, nband int, exclude_nodata_value boolean, sample_percent double precision) -> set of records
1972
1973		the parameter "bins" is removed and set to NULL so that function can compute the number of bins to use
1974
1975		5. ST_ApproxHistogram(rast raster, nband int, sample_percent double precision) -> set of records
1976
1977		exclude_nodata_value is assumed to be TRUE
1978
1979		6. ST_ApproxHistogram(rast raster, nband int) -> set of records
1980
1981		assumes that sample_percent is 0.1
1982
1983		7. ST_ApproxHistogram(rast raster, sample_percent double_precision) -> set of records
1984
1985		assumes that nband is 1
1986
1987		8. ST_ApproxHistogram(rast raster) -> set of records
1988
1989		assumes that nband is 1 and sample_percent is 0.1
1990
1991		9. ST_ApproxHistogram(rast raster, nband int, sample_percent double precision, bins int, width double precision[], right boolean) -> set of records
1992
1993		exclude_nodata_value is assumed to be TRUE
1994
1995		10. ST_ApproxHistogram(rast raster, nband int, sample_percent double precision, bins int, right boolean) -> set of records
1996
1997		all bins will have equal widths
1998
1999		11. ST_ApproxHistogram(rast raster, nband int, sample_percent double precision, bins int) -> set of records
2000
2001		right is assumed to be FALSE
2002
2003		The following set of function are for coverages.
2004
2005		1. ST_Histogram(rastertable text, rastercolumn text, nband int DEFAULT 1, exclude_nodata_value boolean DEFAULT TRUE, bins int default 0, width double precision[] DEFAULT NULL, right boolean DEFAULT FALSE) -> set of records
2006
2007		rastertable: name of table with raster column
2008
2009		rastercolumn: name of column of data type raster
2010
2011		{{{
2012		ST_Histogram('tmax_2010', 'rast')
2013
2014		ST_Histogram('precip_2011', 'rast', 1)
2015
2016		ST_Histogram('precip_2011', 'rast', 1, FALSE)
2017
2018		ST_Histogram('precip_2011', 'rast', 1, FALSE, 5)
2019
2020		ST_Histogram('precip_2011', 'rast', 1, FALSE, 10, NULL)
2021
2022		ST_Histogram('precip_2011', 'rast', 1, FALSE, 10, NULL, TRUE)
2023		}}}
2024
2025		2. ST_Histogram(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean, bins int, right boolean) -> set of records
2026
2027		{{{
2028		ST_Histogram('tmin_2010', 'rast', 2, FALSE, 5, FALSE)
2029		}}}
2030
2031		3. ST_Histogram(rastertable text, rastercolumn text, nband int, bins int, width double precision[] DEFAULT NULL, right boolean DEFAULT FALSE) -> set of records
2032
2033		{{{
2034		ST_Histogram('ndvi_2010', 'rast', 1, 5)
2035
2036		ST_Histogram('ndvi_2010', 'rast', 1, 0, ARRAY[0.5]::double precision[])
2037
2038		ST_Histogram('ndvi_2010', 'rast', 1, 5, NULL, TRUE)
2039		}}}
2040
2041		4. ST_Histogram(rastertable text, rastercolumn text, nband int, bins int, right boolean) -> set of records
2042
2043		{{{
2044		ST_Histogram('veg_2009', 'rast', 2, 3, FALSE)
2045
2046		ST_Histogram('veg_2009', 'rast', 2, 3, TRUE)
2047		}}}
2048
2049		A set of functions of ST_ApproxHistogram for coverage tables:
2050
2051		1. ST_ApproxHistogram(rastertable text, rastercolumn text, nband int DEFAULT 1, exclude_nodata_value boolean DEFAULT TRUE, sample_percent double precision DEFAULT 0.1, bins int DEFAULT 0, width double precision[] DEFAULT NULL, right boolean DEFAULT FALSE) -> set of records
2052
2053		{{{
2054		ST_ApproxHistogram('precip_2010', 'rast')
2055
2056		ST_ApproxHistogram('precip_2010', 'rast', 1)
2057
2058		ST_ApproxHistogram('precip_2010', 'rast', 2, FALSE)
2059
2060		ST_ApproxHistogram('precip_2010', 'rast', 1, TRUE, 0.25)
2061
2062		ST_ApproxHistogram('precip_2010', 'rast', 3, FALSE, 0.2, 10)
2063
2064		ST_ApproxHistogram('precip_2010', 'rast', 1, TRUE, 0.1, 0, ARRAY[1]::double precision[])
2065
2066		ST_ApproxHistogram('precip_2010', 'rast', 1, TRUE, 0.1, 0, ARRAY[1]::double precision[], FALSE)
2067		}}}
2068
2069		2. ST_ApproxHistogram(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean, sample_percent double precision, bins int, right boolean)
2070
2071		3. ST_ApproxHistogram(rastertable text, rastercolumn text, nband int, sample_percent double precision)
2072
2073		4. ST_ApproxHistogram(rastertable text, rastercolumn text, sample_percent double precision)
2074
2075		5. ST_ApproxHistogram(rastertable text, rastercolumn text, nband int, sample_percent double precision, bins int, width double precision[] DEFAULT NULL, right boolean DEFAULT FALSE)
2076
2077		6. ST_ApproxHistogram(rastertable text, rastercolumn text, nband int, sample_percent double precision, bins int, right boolean)
2078
2079		----
2080		'''ST_Quantile(raster, nband) -> set of records'''[[BR]]
2081		In addition to determining the histogram of a raster, providing the ability to compute quantiles permits a user to reference a value in the context of the sample or population. Thus, a value could be examined to be at the raster's 25%, 50%, 75% percentile.
2082
2083		http://en.wikipedia.org/wiki/Quantile
2084
2085		ST_Quantile variations:
2086
2087		1. ST_Quantile(rast raster, nband int, exclude_nodata_value boolean, quantiles double precision[]) -> set of records
2088
2089		each row returned is of (quantile double precision, value double precision)
2090
2091		nband: index of band to process on
2092
2093		exclude_nodata_value: if FALSE, nodata values in band are included. if TRUE, nodata values are not included.
2094
2095		quantiles: array of percentages to compute values for
2096
2097		{{{
2098		ST_Quantile(rast, 1, FALSE, ARRAY[0.1, 0.3, 0.7])
2099
2100		ST_Quantile(rast, 1, TRUE, ARRAY[0.2])
2101
2102		ST_Quantile(rast, 1, FALSE, ARRAY[0, 1])
2103		}}}
2104
2105		2. ST_Quantile(rast raster, nband int, quantiles double precision[]) -> set of records
2106
2107		"exclude_nodata_value" is assumed to be TRUE
2108
2109		{{{
2110		ST_Quantile(rast, 1, ARRAY[0.1, 0.3, 0.7])
2111		}}}
2112
2113		3. ST_Quantile(rast raster, nband int, exclude_nodata_value boolean) -> set of records
2114
2115		"quantiles" assumed to be ARRAY[0, 0.25, 0.5, 0.75, 1]
2116
2117		4. ST_Quantile(rast raster, nband int) -> set of records
2118
2119		"exclude_nodata_value" is assumed to be TRUE and "quantiles" assumed to be ARRAY[0, 0.25, 0.5, 0.75, 1]
2120
2121		5. ST_Quantile(rast raster, quantiles double precision[]) -> set of records
2122
2123		"nband" is assumed to be 1 and "exclude_nodata_value" is TRUE
2124
2125		6. ST_Quantile(rast raster) -> set of records
2126
2127		"nband" is assumed to be 1 and "quantiles" assumed to be ARRAY[0, 0.25, 0.5, 0.75, 1]
2128
2129		7. ST_Quantile(rast raster, nband int, exclude_nodata_value boolean, quantile double precision) -> record
2130
2131		quantile: the single percentile to compute
2132
2133		8. ST_Quantile(rast raster, nband int, quantile double precision) -> record
2134
2135		"exclude_nodata_value" is assumed to be TRUE
2136
2137		9. ST_Quantile(rast raster, exclude_nodata_value boolean, quantile double precision) -> record
2138
2139		"nband" is assumed to be 1
2140
2141		10. ST_Quantile(rast raster, quantile double precision) -> record
2142
2143		"nband" is assumed to be 1 and "exclude_nodata_value" is assumed to be TRUE
2144
2145		ST_ApproxQuantile adds a "sample_percent" indicating the percentage of the raster to sample
2146
2147		1. ST_ApproxQuantile(rast raster, nband int, exclude_nodata_value boolean, sample_percent double precision, quantiles double precision[]) -> set of records
2148
2149		nband: index of band to process on
2150
2151		exclude_nodata_value: if FALSE, nodata values in band are included. if TRUE, nodata values are not included.
2152
2153		sample_percent: a value between 0 and 1 indicating the percentage of the raster band's pixels to consider when computing the quantiles
2154
2155		quantiles: array of percentages to compute values for
2156
2157		{{{
2158		ST_ApproxQuantile(rast, 1, FALSE, 0.1, ARRAY[0.1, 0.3, 0.7])
2159
2160		ST_ApproxQuantile(rast, 1, TRUE, .2, ARRAY[0.2])
2161
2162		ST_ApproxQuantile(rast, 1, FALSE, 0.3, ARRAY[0, 1])
2163		}}}
2164
2165		2. ST_ApproxQuantile(rast raster, nband int, sample_percent double precision, quantiles double precision[]) -> set of records
2166
2167		"exclude_nodata_value" is assumed to be TRUE
2168
2169		{{{
2170		ST_ApproxQuantile(rast, 1, .05, ARRAY[0.1, 0.3, 0.7])
2171		}}}
2172
2173		3. ST_ApproxQuantile(rast raster, nband int, sample_percent double precision) -> set of records
2174
2175		"exclude_nodata_value" is assumed to be TRUE and "quantiles" assumed to be ARRAY[0, 0.25, 0.5, 0.75, 1]
2176
2177		4. ST_ApproxQuantile(rast raster, sample_percent double precision, quantiles double precision[]) -> set of records
2178
2179		"nband" is assumed to be 1
2180
2181		5. ST_ApproxQuantile(rast raster, nband int, sample_percent double precision, quantile double precision) -> record
2182
2183		quantile: the single percentile to compute
2184
2185		6. ST_ApproxQuantile(rast raster, sample_percent double precision, quantile double precision) -> record
2186
2187		"nband" is assumed to be 2
2188
2189		7. ST_ApproxQuantile(rast raster, sample_percent double precision) -> set of records
2190
2191		"nband" is assumed to be 1 and "quantiles" assumed to be ARRAY[0, 0.25, 0.5, 0.75, 1]
2192
2193		8. ST_ApproxQuantile(rast raster, nband int, quantile double precision) -> record
2194
2195		"sample_percent" assumed to be 0.1
2196
2197		9. ST_ApproxQuantile(rast raster, quantiles double precision[]) -> set of records
2198
2199		"nband" is assumed to be 1 and "sample_percent" assumed to be 0.1
2200
2201		10. ST_ApproxQuantile(rast raster, quantile double precision) -> record
2202
2203		"nband" assumed to be 1 and "sample_percent" assumed to be 0.1
2204
2205		11. ST_ApproxQuantile(rast raster, nband int) -> set of records
2206
2207		"quantiles" assumed to be ARRAY[0, 0.25, 0.5, 0.75, 1] and "sample_percent" assumed to be 0.1
2208
2209		12. ST_ApproxQuantile(rast raster) -> set of records
2210
2211		"nband" is assumed to be 1, "quantiles" assumed to be ARRAY[0, 0.25, 0.5, 0.75, 1] and "sample_percent" assumed to be 0.1
	773
2212	774
2213	775	----
…	…
2910	1472	ST_Reclass(rast, '0-100:0-10', '8BUI', 11)
2911	1473	}}}
	1474
	1475	----
	1476	== '''Objective FV.16 - Being able to quickly get raster statistics.''' ==
	1477
	1478	'''Add cached basic raster statistic to the base raster WKB format.
	1479
	1480	Statistics to be cached should include:
	1481
	1482	min/max[[BR]]
	1483	mean[[BR]]
	1484	standard deviation[[BR]]
	1485	histogram[[BR]]
	1486	build parameters of stats (sample rate, method used to determine # of bins in histogram?)[[BR]]
	1487
	1488	How are the statistics to be kept fresh? Automatically using some method to see how much of the raster has changed since the last stats calculation? Or let the user decide?
	1489
	1490	----
	1491
	1492	'''ST_SummaryStats(raster, nband) -> record'''[[BR]]
	1493	This is the core function that gets the summary statistics (# of values, mean, standard deviation, minimum value, maximum value) of a specified raster's band. It is this function that ST_Mean, ST_StdDev and ST_MinMax calls for their appropriate values.
	1494
	1495	1. ST_SummaryStats(rast raster, nband int, exclude_nodata_value boolean) -> record
	1496
	1497	returns one record of five columns (count, mean, stddev, min, max)
	1498
	1499	nband: index of band
	1500
	1501	exclude_nodata_value: if FALSE, nodata values in band are included in the stats. if TRUE, nodata values are not included
	1502
	1503	{{{
	1504	ST_SummaryStats(rast, 1, FALSE)
	1505	}}}
	1506
	1507	2. ST_SummaryStats(rast raster, nband int) -> record
	1508
	1509	assumes exclude_nodata_value = TRUE
	1510
	1511	{{{
	1512	ST_SummaryStats(rast, 2)
	1513	}}}
	1514
	1515	3. ST_SummaryStats(rast raster, exclude_nodata_value boolean) -> record
	1516
	1517	assumes nband = 1
	1518
	1519	{{{
	1520	ST_SummaryStats(rast, TRUE)
	1521	}}}
	1522
	1523	4. ST_SummaryStats(rast raster) -> record
	1524
	1525	assumes nband = 1 and exclude_nodata_value = TRUE
	1526
	1527	{{{
	1528	ST_SummaryStats(rast)
	1529	}}}
	1530
	1531	Due to the time it may take to do on-the-fly calculation of summary stats for large rasters (say 10000 x 10000), an alternative that sacrifices accuracy for speed is required. The following functions sample a percentage of the raster in a methodical randomized manner. The algorithm used for sampling is...
	1532
	1533	1. select the larger dimension of the width and height. compute the number of pixels to sample in each "row" of the larger dimension
	1534
	1535	2. pick pixels from each "row" of the larger dimension in an incremental rolling manner where each increment is randomly determined.
	1536
	1537	The set of ST_ApproxSummaryStats functions are:
	1538
	1539	1. ST_ApproxSummaryStats(rast raster, nband int, exclude_nodata_value boolean, sample_percent double precision) -> record
	1540
	1541	sample_percent: a value between 0 and 1 indicating the percentage of the raster band's pixels to consider
	1542
	1543	{{{
	1544	ST_ApproxSummaryStats(rast, 3, FALSE, 0.1)
	1545
	1546	ST_ApproxSummaryStats(rast, 1, TRUE, 0.5)
	1547	}}}
	1548
	1549	2. ST_ApproxSummaryStats(rast raster, nband int, sample_percent double precision) -> record
	1550
	1551	assumes that nband = 1
	1552
	1553	{{{
	1554	ST_ApproxSummaryStats(rast, 2 0.01)
	1555
	1556	ST_ApproxSummaryStats(rast, 4, 0.025)
	1557	}}}
	1558
	1559	3. ST_ApproxSummaryStats(rast raster, exclude_nodata_value boolean, sample_percent double precision) -> record
	1560
	1561	assumes that nband = 1
	1562
	1563	{{{
	1564	ST_ApproxSummaryStats(rast, FALSE, 0.01)
	1565
	1566	ST_ApproxSummaryStats(rast, TRUE, 0.025)
	1567	}}}
	1568
	1569	4. ST_ApproxSummaryStats(rast raster, sample_percent double precision) -> record
	1570
	1571	assumes that nband = 1 and exclude_nodata_value = TRUE
	1572
	1573	{{{
	1574	ST_ApproxSummaryStats(rast, 0.25)
	1575	}}}
	1576
	1577	5. ST_ApproxSummaryStats(rast raster) -> record
	1578
	1579	assumes that nband = 1, exclude_nodata_value = TRUE and sample_percent = 0.1
	1580
	1581	{{{
	1582	ST_ApproxSummaryStats(rast)
	1583	}}}
	1584
	1585	The situation arises where the summary statistics of a coverage table is required. As the coverage may be large (tens of gigabytes of memory or larger), the following functions are provided to permit an incremental computation of the summary statistics.
	1586
	1587	1. ST_SummaryStats(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean) -> record
	1588
	1589	rastertable: name of table with raster column
	1590
	1591	rastercolumn: name of column of data type raster
	1592
	1593	{{{
	1594	ST_SummaryStats('tmax_2010', 'rast', 1, FALSE)
	1595
	1596	ST_SummaryStats('precip_2011', 'rast', 1, TRUE)
	1597	}}}
	1598
	1599	2. ST_SummaryStats(rastertable text, rastercolumn text, nband int) -> record
	1600
	1601	exclude_nodata_value = TRUE
	1602
	1603	{{{
	1604	ST_SummaryStats('tmax_2010', 'rast', 1)
	1605	}}}
	1606
	1607	3. ST_SummaryStats(rastertable text, rastercolumn text, exclude_nodata_value boolean) -> record
	1608
	1609	nband = 1
	1610
	1611	{{{
	1612	ST_SummaryStats('precip_2011', 'rast', TRUE)
	1613	}}}
	1614
	1615	4. ST_SummaryStats(rastertable text, rastercolumn text) -> record
	1616
	1617	nband = 1 and exclude_nodata_value = TRUE
	1618
	1619	{{{
	1620	ST_SummaryStats('tmin_2009', 'rast')
	1621	}}}
	1622
	1623	Variations for ST_ApproxSummaryStats are:
	1624
	1625	1. ST_ApproxSummaryStats(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean, sample_percent double precision) -> record
	1626
	1627	{{{
	1628	ST_ApproxSummaryStats('tmax_2010', 'rast', 1, FALSE, 0.5)
	1629
	1630	ST_ApproxSummaryStats('precip_2011', 'rast', 1, TRUE, 0.2)
	1631	}}}
	1632
	1633	2. ST_ApproxSummaryStats(rastertable text, rastercolumn text, nband int, sample_percent double precision) -> record
	1634
	1635	exclude_nodata_value = TRUE
	1636
	1637	{{{
	1638	ST_ApproxSummaryStats('tmax_2010', 'rast', 1, 0.5)
	1639
	1640	ST_ApproxSummaryStats('precip_2011', 'rast', 1, 0.2)
	1641	}}}
	1642
	1643	3. ST_ApproxSummaryStats(rastertable text, rastercolumn text, exclude_nodata_value boolean, sample_percent double precision) -> record
	1644
	1645	nband = 1
	1646
	1647	{{{
	1648	ST_ApproxSummaryStats('tmax_2010', 'rast', FALSE, 0.5)
	1649
	1650	ST_ApproxSummaryStats('precip_2011', 'rast', TRUE, 0.2)
	1651	}}}
	1652
	1653	4. ST_ApproxSummaryStats(rastertable text, rastercolumn text, sample_percent double precision) -> record
	1654
	1655	nband = 1 and exclude_nodata_value = TRUE
	1656
	1657	{{{
	1658	ST_ApproxSummaryStats('tmax_2010', 'rast', 0.5)
	1659
	1660	ST_ApproxSummaryStats('precip_2011', 'rast', 0.2)
	1661	}}}
	1662
	1663	5. ST_ApproxSummaryStats(rastertable text, rastercolumn text) -> record
	1664
	1665	nband = 1, exclude_nodata_value = TRUE and sample_percent = 0.1
	1666
	1667	{{{
	1668	ST_ApproxSummaryStats('tmax_2010', 'rast')
	1669
	1670	ST_ApproxSummaryStats('precip_2011', 'rast')
	1671	}}}
	1672
	1673	The mean returned in the coverage functions (has rastertable and rastercolumn arguments) is the true mean of the raster tiles. The standard deviation returned is the standard deviation of all raster tiles.
	1674
	1675	----
	1676
	1677	'''ST_Count(raster, nband) -> bigint'''[[BR]]
	1678
	1679	This function calls ST_SummaryStats and only returns the count from that function.
	1680
	1681	1. ST_Count(rast raster, nband int, exclude_nodata_value boolean) -> bigint
	1682
	1683	returns the count as an integer
	1684
	1685	nband: index of band
	1686
	1687	exclude_nodata_value: if FALSE, nodata values in band are included in the stats. if TRUE, nodata values are not included
	1688
	1689	{{{
	1690	ST_Count(rast, 1, FALSE)
	1691	}}}
	1692
	1693	2. ST_Count(rast raster, nband int) -> bigint
	1694
	1695	assumes exclude_nodata_value = TRUE
	1696
	1697	{{{
	1698	ST_Count(rast, 2)
	1699	}}}
	1700
	1701	3. ST_Count(rast raster, exclude_nodata_value boolean) -> bigint
	1702
	1703	assumes nband = 1
	1704
	1705	{{{
	1706	ST_Count(rast, TRUE)
	1707	}}}
	1708
	1709	4. ST_Count(rast raster) -> bigint
	1710
	1711	assumes nband = 1 and exclude_nodata_value = TRUE
	1712
	1713	{{{
	1714	ST_Count(rast)
	1715	}}}
	1716
	1717	The set of ST_ApproxCount functions are:
	1718
	1719	1. ST_ApproxCount(rast raster, nband int, exclude_nodata_value boolean, sample_percent double precision) -> bigint
	1720
	1721	sample_percent: a value between 0 and 1 indicating the percentage of the raster band's pixels to consider
	1722
	1723	{{{
	1724	ST_ApproxCount(rast, 3, FALSE, 0.1)
	1725
	1726	ST_ApproxCount(rast, 1, TRUE, 0.5)
	1727	}}}
	1728
	1729	2. ST_ApproxCount(rast raster, nband int, sample_percent double precision) -> bigint
	1730
	1731	assumes that nband = 1
	1732
	1733	{{{
	1734	ST_ApproxCount(rast, 2 0.01)
	1735
	1736	ST_ApproxCount(rast, 4, 0.025)
	1737	}}}
	1738
	1739	3. ST_ApproxCount(rast raster, exclude_nodata_value boolean, sample_percent double precision) -> bigint
	1740
	1741	assumes that nband = 1
	1742
	1743	{{{
	1744	ST_ApproxCount(rast, FALSE, 0.01)
	1745
	1746	ST_ApproxCount(rast, TRUE, 0.025)
	1747	}}}
	1748
	1749	4. ST_ApproxCount(rast raster, sample_percent double precision) -> bigint
	1750
	1751	assumes that nband = 1 and exclude_nodata_value = TRUE
	1752
	1753	{{{
	1754	ST_ApproxCount(rast, 0.25)
	1755	}}}
	1756
	1757	5. ST_ApproxCount(rast raster) -> bigint
	1758
	1759	assumes that nband = 1, exclude_nodata_value = TRUE and sample_percent = 0.1
	1760
	1761	{{{
	1762	ST_ApproxCount(rast)
	1763	}}}
	1764
	1765	The following functions are provided for coverage tables.
	1766
	1767	1. ST_Count(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean) -> bigint
	1768
	1769	rastertable: name of table with raster column
	1770
	1771	rastercolumn: name of column of data type raster
	1772
	1773	{{{
	1774	ST_Count('tmax_2010', 'rast', 1, FALSE)
	1775
	1776	ST_Count('precip_2011', 'rast', 1, TRUE)
	1777	}}}
	1778
	1779	2. ST_Count(rastertable text, rastercolumn text, nband int) -> bigint
	1780
	1781	exclude_nodata_value = TRUE
	1782
	1783	{{{
	1784	ST_Count('tmax_2010', 'rast', 1)
	1785	}}}
	1786
	1787	3. ST_Count(rastertable text, rastercolumn text, exclude_nodata_value boolean) -> bigint
	1788
	1789	nband = 1
	1790
	1791	{{{
	1792	ST_Count('precip_2011', 'rast', TRUE)
	1793	}}}
	1794
	1795	4. ST_Count(rastertable text, rastercolumn text) -> bigint
	1796
	1797	nband = 1 and exclude_nodata_value = TRUE
	1798
	1799	{{{
	1800	ST_Count('tmin_2009', 'rast')
	1801	}}}
	1802
	1803	Variations for ST_ApproxCount are:
	1804
	1805	1. ST_ApproxCount(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean, sample_percent double precision) -> bigint
	1806
	1807	{{{
	1808	ST_ApproxCount('tmax_2010', 'rast', 1, FALSE, 0.5)
	1809
	1810	ST_ApproxCount('precip_2011', 'rast', 1, TRUE, 0.2)
	1811	}}}
	1812
	1813	2. ST_ApproxCount(rastertable text, rastercolumn text, nband int, sample_percent double precision) -> bigint
	1814
	1815	exclude_nodata_value = TRUE
	1816
	1817	{{{
	1818	ST_ApproxCount('tmax_2010', 'rast', 1, 0.5)
	1819
	1820	ST_ApproxCount('precip_2011', 'rast', 1, 0.2)
	1821	}}}
	1822
	1823	3. ST_ApproxCount(rastertable text, rastercolumn text, exclude_nodata_value boolean, sample_percent double precision) -> bigint
	1824
	1825	nband = 1
	1826
	1827	{{{
	1828	ST_ApproxCount('tmax_2010', 'rast', FALSE, 0.5)
	1829
	1830	ST_ApproxCount('precip_2011', 'rast', TRUE, 0.2)
	1831	}}}
	1832
	1833	4. ST_ApproxCount(rastertable text, rastercolumn text, sample_percent double precision) -> bigint
	1834
	1835	nband = 1 and exclude_nodata_value = TRUE
	1836
	1837	{{{
	1838	ST_ApproxCount('tmax_2010', 'rast', 0.5)
	1839
	1840	ST_ApproxCount('precip_2011', 'rast', 0.2)
	1841	}}}
	1842
	1843	5. ST_ApproxCount(rastertable text, rastercolumn text) -> bigint
	1844
	1845	nband = 1, exclude_nodata_value = TRUE and sample_percent = 0.1
	1846
	1847	{{{
	1848	ST_ApproxCount('tmax_2010', 'rast')
	1849
	1850	ST_ApproxCount('precip_2011', 'rast')
	1851	}}}
	1852
	1853	----
	1854
	1855	'''ST_Sum(raster, nband) -> double precision'''[[BR]]
	1856
	1857	This function calls ST_SummaryStats and only returns the sum from that function.
	1858
	1859	1. ST_Sum(rast raster, nband int, exclude_nodata_value boolean) -> double precision
	1860
	1861	returns the sum as an integer
	1862
	1863	nband: index of band
	1864
	1865	exclude_nodata_value: if FALSE, nodata values in band are included in the stats. if TRUE, nodata values are not included
	1866
	1867	{{{
	1868	ST_Sum(rast, 1, FALSE)
	1869	}}}
	1870
	1871	2. ST_Sum(rast raster, nband int) -> double precision
	1872
	1873	assumes exclude_nodata_value = TRUE
	1874
	1875	{{{
	1876	ST_Sum(rast, 2)
	1877	}}}
	1878
	1879	3. ST_Sum(rast raster, exclude_nodata_value boolean) -> double precision
	1880
	1881	assumes nband = 1
	1882
	1883	{{{
	1884	ST_Sum(rast, TRUE)
	1885	}}}
	1886
	1887	4. ST_Sum(rast raster) -> double precision
	1888
	1889	assumes nband = 1 and exclude_nodata_value = TRUE
	1890
	1891	{{{
	1892	ST_Sum(rast)
	1893	}}}
	1894
	1895	The set of ST_ApproxSum functions are:
	1896
	1897	1. ST_ApproxSum(rast raster, nband int, exclude_nodata_value boolean, sample_percent double precision) -> double precision
	1898
	1899	sample_percent: a value between 0 and 1 indicating the percentage of the raster band's pixels to consider
	1900
	1901	{{{
	1902	ST_ApproxSum(rast, 3, FALSE, 0.1)
	1903
	1904	ST_ApproxSum(rast, 1, TRUE, 0.5)
	1905	}}}
	1906
	1907	2. ST_ApproxSum(rast raster, nband int, sample_percent double precision) -> double precision
	1908
	1909	assumes that nband = 1
	1910
	1911	{{{
	1912	ST_ApproxSum(rast, 2 0.01)
	1913
	1914	ST_ApproxSum(rast, 4, 0.025)
	1915	}}}
	1916
	1917	3. ST_ApproxSum(rast raster, exclude_nodata_value boolean, sample_percent double precision) -> double precision
	1918
	1919	assumes that nband = 1
	1920
	1921	{{{
	1922	ST_ApproxSum(rast, FALSE, 0.01)
	1923
	1924	ST_ApproxSum(rast, TRUE, 0.025)
	1925	}}}
	1926
	1927	4. ST_ApproxSum(rast raster, sample_percent double precision) -> double precision
	1928
	1929	assumes that nband = 1 and exclude_nodata_value = TRUE
	1930
	1931	{{{
	1932	ST_ApproxSum(rast, 0.25)
	1933	}}}
	1934
	1935	5. ST_ApproxSum(rast raster) -> double precision
	1936
	1937	assumes that nband = 1, exclude_nodata_value = TRUE and sample_percent = 0.1
	1938
	1939	{{{
	1940	ST_ApproxSum(rast)
	1941	}}}
	1942
	1943	The following functions are provided for coverage tables.
	1944
	1945	1. ST_Sum(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean) -> double precision
	1946
	1947	rastertable: name of table with raster column
	1948
	1949	rastercolumn: name of column of data type raster
	1950
	1951	{{{
	1952	ST_Sum('tmax_2010', 'rast', 1, FALSE)
	1953
	1954	ST_Sum('precip_2011', 'rast', 1, TRUE)
	1955	}}}
	1956
	1957	2. ST_Sum(rastertable text, rastercolumn text, nband int) -> double precision
	1958
	1959	exclude_nodata_value = TRUE
	1960
	1961	{{{
	1962	ST_Sum('tmax_2010', 'rast', 1)
	1963	}}}
	1964
	1965	3. ST_Sum(rastertable text, rastercolumn text, exclude_nodata_value boolean) -> double precision
	1966
	1967	nband = 1
	1968
	1969	{{{
	1970	ST_Sum('precip_2011', 'rast', TRUE)
	1971	}}}
	1972
	1973	4. ST_Sum(rastertable text, rastercolumn text) -> double precision
	1974
	1975	nband = 1 and exclude_nodata_value = TRUE
	1976
	1977	{{{
	1978	ST_Sum('tmin_2009', 'rast')
	1979	}}}
	1980
	1981	Variations for ST_ApproxSum are:
	1982
	1983	1. ST_ApproxSum(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean, sample_percent double precision) -> double precision
	1984
	1985	{{{
	1986	ST_ApproxSum('tmax_2010', 'rast', 1, FALSE, 0.5)
	1987
	1988	ST_ApproxSum('precip_2011', 'rast', 1, TRUE, 0.2)
	1989	}}}
	1990
	1991	2. ST_ApproxSum(rastertable text, rastercolumn text, nband int, sample_percent double precision) -> double precision
	1992
	1993	exclude_nodata_value = TRUE
	1994
	1995	{{{
	1996	ST_ApproxSum('tmax_2010', 'rast', 1, 0.5)
	1997
	1998	ST_ApproxSum('precip_2011', 'rast', 1, 0.2)
	1999	}}}
	2000
	2001	3. ST_ApproxSum(rastertable text, rastercolumn text, exclude_nodata_value boolean, sample_percent double precision) -> double precision
	2002
	2003	nband = 1
	2004
	2005	{{{
	2006	ST_ApproxSum('tmax_2010', 'rast', FALSE, 0.5)
	2007
	2008	ST_ApproxSum('precip_2011', 'rast', TRUE, 0.2)
	2009	}}}
	2010
	2011	4. ST_ApproxSum(rastertable text, rastercolumn text, sample_percent double precision) -> double precision
	2012
	2013	nband = 1 and exclude_nodata_value = TRUE
	2014
	2015	{{{
	2016	ST_ApproxSum('tmax_2010', 'rast', 0.5)
	2017
	2018	ST_ApproxSum('precip_2011', 'rast', 0.2)
	2019	}}}
	2020
	2021	5. ST_ApproxSum(rastertable text, rastercolumn text) -> double precision
	2022
	2023	nband = 1, exclude_nodata_value = TRUE and sample_percent = 0.1
	2024
	2025	{{{
	2026	ST_ApproxSum('tmax_2010', 'rast')
	2027
	2028	ST_ApproxSum('precip_2011', 'rast')
	2029	}}}
	2030
	2031	----
	2032
	2033	'''ST_Mean(raster, nband) -> double precision'''[[BR]]
	2034	This function calls ST_SummaryStats and only returns the mean from that function.
	2035
	2036	1. ST_Mean(rast raster, nband int, exclude_nodata_value boolean) -> double precision
	2037
	2038	returns the mean as a double precision
	2039
	2040	nband: index of band
	2041
	2042	exclude_nodata_value: if FALSE, nodata values in band are included. if TRUE, nodata values are not included.
	2043
	2044	{{{
	2045	ST_Mean(rast, 1, FALSE)
	2046	}}}
	2047
	2048	2. ST_Mean(rast raster, nband int) -> double precision
	2049
	2050	assumes exclude_nodata_value = TRUE
	2051
	2052	{{{
	2053	ST_Mean(rast, 2)
	2054	}}}
	2055
	2056	3. ST_Mean(rast raster, exclude_nodata_value boolean) -> double precision
	2057
	2058	assumes nband = 1
	2059
	2060	{{{
	2061	ST_Mean(rast, TRUE)
	2062	}}}
	2063
	2064	4. ST_Mean(rast raster) -> double precision
	2065
	2066	assumes nband = 1 and exclude_nodata_value = TRUE
	2067
	2068	{{{
	2069	ST_Mean(rast)
	2070	}}}
	2071
	2072	The set of ST_ApproxMean functions are:
	2073
	2074	1. ST_ApproxMean(rast raster, nband int, exclude_nodata_value boolean, sample_percent double precision) -> double precision
	2075
	2076	sample_percent: a value between 0 and 1 indicating the percentage of the raster band's pixels to consider
	2077
	2078	{{{
	2079	ST_ApproxMean(rast, 3, FALSE, 0.1)
	2080
	2081	ST_ApproxMean(rast, 1, TRUE, 0.5)
	2082	}}}
	2083
	2084	2. ST_ApproxMean(rast raster, nband int, sample_percent double precision) -> double precision
	2085
	2086	assumes that nband = 1
	2087
	2088	{{{
	2089	ST_ApproxMean(rast, 2 0.01)
	2090
	2091	ST_ApproxMean(rast, 4, 0.025)
	2092	}}}
	2093
	2094	3. ST_ApproxMean(rast raster, exclude_nodata_value boolean, sample_percent double precision) -> double precision
	2095
	2096	assumes that nband = 1
	2097
	2098	{{{
	2099	ST_ApproxMean(rast, FALSE, 0.01)
	2100
	2101	ST_ApproxMean(rast, TRUE, 0.025)
	2102	}}}
	2103
	2104	4. ST_ApproxMean(rast raster, sample_percent double precision) -> double precision
	2105
	2106	assumes that nband = 1 and exclude_nodata_value = TRUE
	2107
	2108	{{{
	2109	ST_ApproxMean(rast, 0.25)
	2110	}}}
	2111
	2112	5. ST_ApproxMean(rast raster) -> double precision
	2113
	2114	assumes that nband = 1, exclude_nodata_value = TRUE and sample_percent = 0.1
	2115
	2116	{{{
	2117	ST_ApproxMean(rast)
	2118	}}}
	2119
	2120	The following functions are provided for coverage tables.
	2121
	2122	1. ST_Mean(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean) -> double precision
	2123
	2124	rastertable: name of table with raster column
	2125
	2126	rastercolumn: name of column of data type raster
	2127
	2128	{{{
	2129	ST_Mean('tmax_2010', 'rast', 1, FALSE)
	2130
	2131	ST_Mean('precip_2011', 'rast', 1, TRUE)
	2132	}}}
	2133
	2134	2. ST_Mean(rastertable text, rastercolumn text, nband int) -> double precision
	2135
	2136	exclude_nodata_value = TRUE
	2137
	2138	{{{
	2139	ST_Mean('tmax_2010', 'rast', 1)
	2140	}}}
	2141
	2142	3. ST_Mean(rastertable text, rastercolumn text, exclude_nodata_value boolean) -> double precision
	2143
	2144	nband = 1
	2145
	2146	{{{
	2147	ST_Mean('precip_2011', 'rast', TRUE)
	2148	}}}
	2149
	2150	4. ST_Mean(rastertable text, rastercolumn text) -> double precision
	2151
	2152	nband = 1 and exclude_nodata_value = TRUE
	2153
	2154	{{{
	2155	ST_Mean('tmin_2009', 'rast')
	2156	}}}
	2157
	2158	Variations for ST_ApproxMean are:
	2159
	2160	1. ST_ApproxMean(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean, sample_percent double precision) -> double precision
	2161
	2162	{{{
	2163	ST_ApproxMean('tmax_2010', 'rast', 1, FALSE, 0.5)
	2164
	2165	ST_ApproxMean('precip_2011', 'rast', 1, TRUE, 0.2)
	2166	}}}
	2167
	2168	2. ST_ApproxMean(rastertable text, rastercolumn text, nband int, sample_percent double precision) -> double precision
	2169
	2170	exclude_nodata_value = TRUE
	2171
	2172	{{{
	2173	ST_ApproxMean('tmax_2010', 'rast', 1, 0.5)
	2174
	2175	ST_ApproxMean('precip_2011', 'rast', 1, 0.2)
	2176	}}}
	2177
	2178	3. ST_ApproxMean(rastertable text, rastercolumn text, exclude_nodata_value boolean, sample_percent double precision) -> double precision
	2179
	2180	nband = 1
	2181
	2182	{{{
	2183	ST_ApproxMean('tmax_2010', 'rast', FALSE, 0.5)
	2184
	2185	ST_ApproxMean('precip_2011', 'rast', TRUE, 0.2)
	2186	}}}
	2187
	2188	4. ST_ApproxMean(rastertable text, rastercolumn text, sample_percent double precision) -> double precision
	2189
	2190	nband = 1 and exclude_nodata_value = TRUE
	2191
	2192	{{{
	2193	ST_ApproxMean('tmax_2010', 'rast', 0.5)
	2194
	2195	ST_ApproxMean('precip_2011', 'rast', 0.2)
	2196	}}}
	2197
	2198	5. ST_ApproxMean(rastertable text, rastercolumn text) -> double precision
	2199
	2200	nband = 1, exclude_nodata_value = TRUE and sample_percent = 0.1
	2201
	2202	{{{
	2203	ST_ApproxMean('tmax_2010', 'rast')
	2204
	2205	ST_ApproxMean('precip_2011', 'rast')
	2206	}}}
	2207
	2208	The mean returned in the coverage functions (has rastertable and rastercolumn arguments) is the true mean of the raster tiles.
	2209
	2210	----
	2211
	2212	'''ST_StdDev(raster, nband) -> double precision'''[[BR]]
	2213	This function calls ST_SummaryStats and only returns the standard deviation from that function.
	2214
	2215	1. ST_StdDev(rast raster, nband int, exclude_nodata_value boolean) -> double precision
	2216
	2217	returns the standard deviation as a double precision
	2218
	2219	nband: index of band
	2220
	2221	exclude_nodata_value: if FALSE, nodata values in band are included. if TRUE, nodata values are not included.
	2222
	2223	{{{
	2224	ST_StdDev(rast, 1, FALSE)
	2225	}}}
	2226
	2227	2. ST_StdDev(rast raster, nband int) -> double precision
	2228
	2229	assumes exclude_nodata_value = TRUE
	2230
	2231	{{{
	2232	ST_StdDev(rast, 2)
	2233	}}}
	2234
	2235	3. ST_StdDev(rast raster, exclude_nodata_value boolean) -> double precision
	2236
	2237	assumes nband = 1
	2238
	2239	{{{
	2240	ST_StdDev(rast, TRUE)
	2241	}}}
	2242
	2243	4. ST_StdDev(rast raster) -> double precision
	2244
	2245	assumes nband = 1 and exclude_nodata_value = TRUE
	2246
	2247	{{{
	2248	ST_StdDev(rast)
	2249	}}}
	2250
	2251	The set of ST_ApproxStdDev functions are:
	2252
	2253	1. ST_ApproxStdDev(rast raster, nband int, exclude_nodata_value boolean, sample_percent double precision) -> double precision
	2254
	2255	sample_percent: a value between 0 and 1 indicating the percentage of the raster band's pixels to consider
	2256
	2257	{{{
	2258	ST_ApproxStdDev(rast, 3, FALSE, 0.1)
	2259
	2260	ST_ApproxStdDev(rast, 1, TRUE, 0.5)
	2261	}}}
	2262
	2263	2. ST_ApproxStdDev(rast raster, nband int, sample_percent double precision) -> double precision
	2264
	2265	assumes that nband = 1
	2266
	2267	{{{
	2268	ST_ApproxStdDev(rast, 2 0.01)
	2269
	2270	ST_ApproxStdDev(rast, 4, 0.025)
	2271	}}}
	2272
	2273	3. ST_ApproxStdDev(rast raster, exclude_nodata_value boolean, sample_percent double precision) -> double precision
	2274
	2275	assumes that nband = 1
	2276
	2277	{{{
	2278	ST_ApproxStdDev(rast, FALSE, 0.01)
	2279
	2280	ST_ApproxStdDev(rast, TRUE, 0.025)
	2281	}}}
	2282
	2283	4. ST_ApproxStdDev(rast raster, sample_percent double precision) -> double precision
	2284
	2285	assumes that nband = 1 and exclude_nodata_value = TRUE
	2286
	2287	{{{
	2288	ST_ApproxStdDev(rast, 0.25)
	2289	}}}
	2290
	2291	5. ST_ApproxStdDev(rast raster) -> double precision
	2292
	2293	assumes that nband = 1, exclude_nodata_value = TRUE and sample_percent = 0.1
	2294
	2295	{{{
	2296	ST_ApproxStdDev(rast)
	2297	}}}
	2298
	2299	The following functions are provided for coverage tables.
	2300
	2301	1. ST_StdDev(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean) -> double precision
	2302
	2303	rastertable: name of table with raster column
	2304
	2305	rastercolumn: name of column of data type raster
	2306
	2307	{{{
	2308	ST_StdDev('tmax_2010', 'rast', 1, FALSE)
	2309
	2310	ST_StdDev('precip_2011', 'rast', 1, TRUE)
	2311	}}}
	2312
	2313	2. ST_StdDev(rastertable text, rastercolumn text, nband int) -> double precision
	2314
	2315	exclude_nodata_value = TRUE
	2316
	2317	{{{
	2318	ST_StdDev('tmax_2010', 'rast', 1)
	2319	}}}
	2320
	2321	3. ST_StdDev(rastertable text, rastercolumn text, exclude_nodata_value boolean) -> double precision
	2322
	2323	nband = 1
	2324
	2325	{{{
	2326	ST_StdDev('precip_2011', 'rast', TRUE)
	2327	}}}
	2328
	2329	4. ST_StdDev(rastertable text, rastercolumn text) -> double precision
	2330
	2331	nband = 1 and exclude_nodata_value = TRUE
	2332
	2333	{{{
	2334	ST_StdDev('tmin_2009', 'rast')
	2335	}}}
	2336
	2337	Variations for ST_ApproxStdDev are:
	2338
	2339	1. ST_ApproxStdDev(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean, sample_percent double precision) -> double precision
	2340
	2341	{{{
	2342	ST_ApproxStdDev('tmax_2010', 'rast', 1, FALSE, 0.5)
	2343
	2344	ST_ApproxStdDev('precip_2011', 'rast', 1, TRUE, 0.2)
	2345	}}}
	2346
	2347	2. ST_ApproxStdDev(rastertable text, rastercolumn text, nband int, sample_percent double precision) -> double precision
	2348
	2349	exclude_nodata_value = TRUE
	2350
	2351	{{{
	2352	ST_ApproxStdDev('tmax_2010', 'rast', 1, 0.5)
	2353
	2354	ST_ApproxStdDev('precip_2011', 'rast', 1, 0.2)
	2355	}}}
	2356
	2357	3. ST_ApproxStdDev(rastertable text, rastercolumn text, exclude_nodata_value boolean, sample_percent double precision) -> double precision
	2358
	2359	nband = 1
	2360
	2361	{{{
	2362	ST_ApproxStdDev('tmax_2010', 'rast', FALSE, 0.5)
	2363
	2364	ST_ApproxStdDev('precip_2011', 'rast', TRUE, 0.2)
	2365	}}}
	2366
	2367	4. ST_ApproxStdDev(rastertable text, rastercolumn text, sample_percent double precision) -> double precision
	2368
	2369	nband = 1 and exclude_nodata_value = TRUE
	2370
	2371	{{{
	2372	ST_ApproxStdDev('tmax_2010', 'rast', 0.5)
	2373
	2374	ST_ApproxStdDev('precip_2011', 'rast', 0.2)
	2375	}}}
	2376
	2377	5. ST_ApproxStdDev(rastertable text, rastercolumn text) -> double precision
	2378
	2379	nband = 1, exclude_nodata_value = TRUE and sample_percent = 0.1
	2380
	2381	{{{
	2382	ST_ApproxStdDev('tmax_2010', 'rast')
	2383
	2384	ST_ApproxStdDev('precip_2011', 'rast')
	2385	}}}
	2386
	2387	The standard deviation returned in the coverage functions (has rastertable and rastercolumn arguments) is the standard deviation of all raster tiles.
	2388
	2389	----
	2390
	2391	'''ST_MinMax(raster, nband) -> record'''[[BR]]
	2392	This function calls ST_SummaryStats and only returns the min and max values from that function.
	2393
	2394	1. ST_MinMax(rast raster, nband int, exclude_nodata_value boolean) -> record
	2395
	2396	returns the record (min double precision, max double precision)
	2397
	2398	nband: index of band
	2399
	2400	exclude_nodata_value: if FALSE, nodata values in band are included. if TRUE, nodata values are not included.
	2401
	2402	{{{
	2403	ST_MinMax(rast, 1, FALSE)
	2404	}}}
	2405
	2406	2. ST_MinMax(rast raster, nband int) -> record
	2407
	2408	assumes exclude_nodata_value = TRUE
	2409
	2410	{{{
	2411	ST_MinMax(rast, 2)
	2412	}}}
	2413
	2414	3. ST_MinMax(rast raster, exclude_nodata_value boolean) -> record
	2415
	2416	assumes nband = 1
	2417
	2418	{{{
	2419	ST_MinMax(rast, TRUE)
	2420	}}}
	2421
	2422	4. ST_MinMax(rast raster) -> record
	2423
	2424	assumes nband = 1 and exclude_nodata_value = TRUE
	2425
	2426	{{{
	2427	ST_MinMax(rast)
	2428	}}}
	2429
	2430	The set of ST_ApproxMinMax functions are:
	2431
	2432	1. ST_ApproxMinMax(rast raster, nband int, exclude_nodata_value boolean, sample_percent record) -> record
	2433
	2434	sample_percent: a value between 0 and 1 indicating the percentage of the raster band's pixels to consider
	2435
	2436	{{{
	2437	ST_ApproxMinMax(rast, 3, FALSE, 0.1)
	2438
	2439	ST_ApproxMinMax(rast, 1, TRUE, 0.5)
	2440	}}}
	2441
	2442	2. ST_ApproxMinMax(rast raster, nband int, sample_percent double precision) -> record
	2443
	2444	assumes that nband = 1
	2445
	2446	{{{
	2447	ST_ApproxMinMax(rast, 2 0.01)
	2448
	2449	ST_ApproxMinMax(rast, 4, 0.025)
	2450	}}}
	2451
	2452	3. ST_ApproxMinMax(rast raster, exclude_nodata_value boolean, sample_percent double precision) -> record
	2453
	2454	assumes that nband = 1
	2455
	2456	{{{
	2457	ST_ApproxMinMax(rast, FALSE, 0.01)
	2458
	2459	ST_ApproxMinMax(rast, TRUE, 0.025)
	2460	}}}
	2461
	2462	4. ST_ApproxMinMax(rast raster, sample_percent double precision) -> record
	2463
	2464	assumes that nband = 1 and exclude_nodata_value = TRUE
	2465
	2466	{{{
	2467	ST_ApproxMinMax(rast, 0.25)
	2468	}}}
	2469
	2470	5. ST_ApproxMinMax(rast raster) -> record
	2471
	2472	assumes that nband = 1, exclude_nodata_value = TRUE and sample_percent = 0.1
	2473
	2474	{{{
	2475	ST_ApproxMinMax(rast)
	2476	}}}
	2477
	2478	The following functions are provided for coverage tables.
	2479
	2480	1. ST_MinMax(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean) -> record
	2481
	2482	rastertable: name of table with raster column
	2483
	2484	rastercolumn: name of column of data type raster
	2485
	2486	{{{
	2487	ST_MinMax('tmax_2010', 'rast', 1, FALSE)
	2488
	2489	ST_MinMax('precip_2011', 'rast', 1, TRUE)
	2490	}}}
	2491
	2492	2. ST_MinMax(rastertable text, rastercolumn text, nband int) -> record
	2493
	2494	exclude_nodata_value = TRUE
	2495
	2496	{{{
	2497	ST_MinMax('tmax_2010', 'rast', 1)
	2498	}}}
	2499
	2500	3. ST_MinMax(rastertable text, rastercolumn text, exclude_nodata_value boolean) -> record
	2501
	2502	nband = 1
	2503
	2504	{{{
	2505	ST_MinMax('precip_2011', 'rast', TRUE)
	2506	}}}
	2507
	2508	4. ST_MinMax(rastertable text, rastercolumn text) -> record
	2509
	2510	nband = 1 and exclude_nodata_value = TRUE
	2511
	2512	{{{
	2513	ST_MinMax('tmin_2009', 'rast')
	2514	}}}
	2515
	2516	Variations for ST_ApproxMinMax are:
	2517
	2518	1. ST_ApproxMinMax(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean, sample_percent double precision) -> record
	2519
	2520	{{{
	2521	ST_ApproxMinMax('tmax_2010', 'rast', 1, FALSE, 0.5)
	2522
	2523	ST_ApproxMinMax('precip_2011', 'rast', 1, TRUE, 0.2)
	2524	}}}
	2525
	2526	2. ST_ApproxMinMax(rastertable text, rastercolumn text, nband int, sample_percent double precision) -> record
	2527
	2528	exclude_nodata_value = TRUE
	2529
	2530	{{{
	2531	ST_ApproxMinMax('tmax_2010', 'rast', 1, 0.5)
	2532
	2533	ST_ApproxMinMax('precip_2011', 'rast', 1, 0.2)
	2534	}}}
	2535
	2536	3. ST_ApproxMinMax(rastertable text, rastercolumn text, exclude_nodata_value boolean, sample_percent double precision) -> record
	2537
	2538	nband = 1
	2539
	2540	{{{
	2541	ST_ApproxMinMax('tmax_2010', 'rast', FALSE, 0.5)
	2542
	2543	ST_ApproxMinMax('precip_2011', 'rast', TRUE, 0.2)
	2544	}}}
	2545
	2546	4. ST_ApproxMinMax(rastertable text, rastercolumn text, sample_percent double precision) -> record
	2547
	2548	nband = 1 and exclude_nodata_value = TRUE
	2549
	2550	{{{
	2551	ST_ApproxMinMax('tmax_2010', 'rast', 0.5)
	2552
	2553	ST_ApproxMinMax('precip_2011', 'rast', 0.2)
	2554	}}}
	2555
	2556	5. ST_ApproxMinMax(rastertable text, rastercolumn text) -> record
	2557
	2558	nband = 1, exclude_nodata_value = TRUE and sample_percent = 0.1
	2559
	2560	{{{
	2561	ST_ApproxMinMax('tmax_2010', 'rast')
	2562
	2563	ST_ApproxMinMax('precip_2011', 'rast')
	2564	}}}
	2565
	2566	----
	2567
	2568	'''ST_Histogram(raster, nband) -> set of records'''[[BR]]
	2569	ST_Histogram and ST_ApproxHistogram provide methods to determine a raster's data distribution.
	2570
	2571	The return of ST_Histogram and ST_ApproxHistogram is a set of records where each record is (min, max, count, percent).
	2572
	2573	ST_Histogram has the following variations.
	2574
	2575	1. ST_Histogram(rast raster, nband int, exclude_nodata_value boolean, bins int, width double precision[], right boolean) -> set of records
	2576
	2577	returns set of records of four columns (min, max, count, percent)
	2578
	2579	nband: index of band to process on
	2580
	2581	exclude_nodata_value: if FALSE, nodata values in band are included. if TRUE, nodata values are not included.
	2582
	2583	bins: the number of categories/bins to have in the histogram. If NULL or value less than one, the number of categories will be auto-computed using Sturges' formula if the number of values >= 30 or Square-root choice if number of values < 30.
	2584
	2585	http://en.wikipedia.org/wiki/Histogram#Mathematical_definition
	2586
	2587	width: an array indicating the width of each category/bin. If the number of bins is greater than the number of widths, the widths are repeated. Example: 9 bins, widths are [a, b, c] will have the output be [a, b, c, a, b, c, a, b, c].
	2588
	2589	right: compute the histogram from the right rather than from the left (default). This changes the criteria for evaluating a value x from [a, b) to (a, b].
	2590
	2591	{{{
	2592	ST_Histogram(rast, 2, FALSE, NULL, NULL, FALSE)
	2593
	2594	ST_Histogram(rast, 1, TRUE, 100, NULL, FALSE)
	2595
	2596	ST_Histogram(rast, 2, FALSE, NULL, ARRAY[100, 50], FALSE)
	2597
	2598	ST_Histogram(rast, 2, FALSE, 9, ARRAY[1000], TRUE)
	2599
	2600	ST_Histogram(rast, 2, FALSE, 20, ARRAY[100, 200, 300], TRUE)
	2601	}}}
	2602
	2603	2. ST_Histogram(rast raster, nband int, exclude_nodata_value boolean, bins int, right boolean) -> set of records
	2604
	2605	parameter "width" is not specified thus resulting in all bins having the same widths
	2606
	2607	{{{
	2608	ST_Histogram(rast, 2, FALSE, 5, FALSE)
	2609	}}}
	2610
	2611	3. ST_Histogram(rast raster, nband int, exclude_nodata_value boolean, bins int) -> set of records
	2612
	2613	the parameter "right" is removed and assumed to be FALSE
	2614
	2615	{{{
	2616	ST_Histogram(rast, 2, FALSE, 5)
	2617	}}}
	2618
	2619	4. ST_Histogram(rast raster, nband int, exclude_nodata_value boolean) -> set of records
	2620
	2621	the parameter "bins" is removed and set to NULL. The function will compute the number of bins to use
	2622
	2623	5. ST_Histogram(rast raster, nband int) -> set of records
	2624
	2625	exclude_nodata_value is assumed to be TRUE
	2626
	2627	6. ST_Histogram(rast raster) -> set of records
	2628
	2629	assumes that nband is 1.
	2630
	2631	7. ST_Histogram(rast raster, nband int, bins int, width double precision[], right boolean) -> set of records
	2632
	2633	exclude_nodata_value is assumed to be TRUE
	2634
	2635	8. ST_Histogram(rast raster, nband int, bins int, right boolean) -> set of records
	2636
	2637	all bins will have equal widths
	2638
	2639	9. ST_Histogram(rast raster, nband int, bins int) -> set of records
	2640
	2641	right is assumed to be FALSE
	2642
	2643	ST_ApproxHistogram should have the following variations.
	2644
	2645	1. ST_ApproxHistogram(rast raster, nband int, exclude_nodata_value boolean, sample_percent double precision, bins int, width double precision[], right boolean) -> set of record
	2646
	2647	sample_percent: a value between 0 and 1 indicating the percentage of the raster band's pixels to consider when generating the histogram.
	2648
	2649	{{{
	2650	ST_Histogram(rast, 2, FALSE, 0.1, NULL, NULL, FALSE)
	2651
	2652	ST_Histogram(rast, 1, TRUE, 1, 100, NULL, FALSE)
	2653
	2654	ST_Histogram(rast, 2, FALSE, 0.2, NULL, ARRAY[100, 50], FALSE)
	2655
	2656	ST_Histogram(rast, 2, FALSE, 0.25, 9, ARRAY[1000], TRUE)
	2657
	2658	ST_Histogram(rast, 2, FALSE, 0.05, 20, ARRAY[100, 200, 300], TRUE)
	2659	}}}
	2660
	2661	2. ST_ApproxHistogram(rast raster, nband int, exclude_nodata_value boolean, sample_percent double precision, bins int, right boolean) -> set of records
	2662
	2663	parameter "width" is not specified thus resulting in all bins having the same widths
	2664
	2665	3. ST_ApproxHistogram(rast raster, nband int, exclude_nodata_value boolean, sample_percent double precision, bins int) -> set of records
	2666
	2667	the parameter "right" is removed and assumed to be FALSE
	2668
	2669	{{{
	2670	ST_ApproxHistogram(rast, 2, FALSE, 5)
	2671	}}}
	2672
	2673	4. ST_ApproxHistogram(rast raster, nband int, exclude_nodata_value boolean, sample_percent double precision) -> set of records
	2674
	2675	the parameter "bins" is removed and set to NULL so that function can compute the number of bins to use
	2676
	2677	5. ST_ApproxHistogram(rast raster, nband int, sample_percent double precision) -> set of records
	2678
	2679	exclude_nodata_value is assumed to be TRUE
	2680
	2681	6. ST_ApproxHistogram(rast raster, nband int) -> set of records
	2682
	2683	assumes that sample_percent is 0.1
	2684
	2685	7. ST_ApproxHistogram(rast raster, sample_percent double_precision) -> set of records
	2686
	2687	assumes that nband is 1
	2688
	2689	8. ST_ApproxHistogram(rast raster) -> set of records
	2690
	2691	assumes that nband is 1 and sample_percent is 0.1
	2692
	2693	9. ST_ApproxHistogram(rast raster, nband int, sample_percent double precision, bins int, width double precision[], right boolean) -> set of records
	2694
	2695	exclude_nodata_value is assumed to be TRUE
	2696
	2697	10. ST_ApproxHistogram(rast raster, nband int, sample_percent double precision, bins int, right boolean) -> set of records
	2698
	2699	all bins will have equal widths
	2700
	2701	11. ST_ApproxHistogram(rast raster, nband int, sample_percent double precision, bins int) -> set of records
	2702
	2703	right is assumed to be FALSE
	2704
	2705	The following set of function are for coverages.
	2706
	2707	1. ST_Histogram(rastertable text, rastercolumn text, nband int DEFAULT 1, exclude_nodata_value boolean DEFAULT TRUE, bins int default 0, width double precision[] DEFAULT NULL, right boolean DEFAULT FALSE) -> set of records
	2708
	2709	rastertable: name of table with raster column
	2710
	2711	rastercolumn: name of column of data type raster
	2712
	2713	{{{
	2714	ST_Histogram('tmax_2010', 'rast')
	2715
	2716	ST_Histogram('precip_2011', 'rast', 1)
	2717
	2718	ST_Histogram('precip_2011', 'rast', 1, FALSE)
	2719
	2720	ST_Histogram('precip_2011', 'rast', 1, FALSE, 5)
	2721
	2722	ST_Histogram('precip_2011', 'rast', 1, FALSE, 10, NULL)
	2723
	2724	ST_Histogram('precip_2011', 'rast', 1, FALSE, 10, NULL, TRUE)
	2725	}}}
	2726
	2727	2. ST_Histogram(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean, bins int, right boolean) -> set of records
	2728
	2729	{{{
	2730	ST_Histogram('tmin_2010', 'rast', 2, FALSE, 5, FALSE)
	2731	}}}
	2732
	2733	3. ST_Histogram(rastertable text, rastercolumn text, nband int, bins int, width double precision[] DEFAULT NULL, right boolean DEFAULT FALSE) -> set of records
	2734
	2735	{{{
	2736	ST_Histogram('ndvi_2010', 'rast', 1, 5)
	2737
	2738	ST_Histogram('ndvi_2010', 'rast', 1, 0, ARRAY[0.5]::double precision[])
	2739
	2740	ST_Histogram('ndvi_2010', 'rast', 1, 5, NULL, TRUE)
	2741	}}}
	2742
	2743	4. ST_Histogram(rastertable text, rastercolumn text, nband int, bins int, right boolean) -> set of records
	2744
	2745	{{{
	2746	ST_Histogram('veg_2009', 'rast', 2, 3, FALSE)
	2747
	2748	ST_Histogram('veg_2009', 'rast', 2, 3, TRUE)
	2749	}}}
	2750
	2751	A set of functions of ST_ApproxHistogram for coverage tables:
	2752
	2753	1. ST_ApproxHistogram(rastertable text, rastercolumn text, nband int DEFAULT 1, exclude_nodata_value boolean DEFAULT TRUE, sample_percent double precision DEFAULT 0.1, bins int DEFAULT 0, width double precision[] DEFAULT NULL, right boolean DEFAULT FALSE) -> set of records
	2754
	2755	{{{
	2756	ST_ApproxHistogram('precip_2010', 'rast')
	2757
	2758	ST_ApproxHistogram('precip_2010', 'rast', 1)
	2759
	2760	ST_ApproxHistogram('precip_2010', 'rast', 2, FALSE)
	2761
	2762	ST_ApproxHistogram('precip_2010', 'rast', 1, TRUE, 0.25)
	2763
	2764	ST_ApproxHistogram('precip_2010', 'rast', 3, FALSE, 0.2, 10)
	2765
	2766	ST_ApproxHistogram('precip_2010', 'rast', 1, TRUE, 0.1, 0, ARRAY[1]::double precision[])
	2767
	2768	ST_ApproxHistogram('precip_2010', 'rast', 1, TRUE, 0.1, 0, ARRAY[1]::double precision[], FALSE)
	2769	}}}
	2770
	2771	2. ST_ApproxHistogram(rastertable text, rastercolumn text, nband int, exclude_nodata_value boolean, sample_percent double precision, bins int, right boolean)
	2772
	2773	3. ST_ApproxHistogram(rastertable text, rastercolumn text, nband int, sample_percent double precision)
	2774
	2775	4. ST_ApproxHistogram(rastertable text, rastercolumn text, sample_percent double precision)
	2776
	2777	5. ST_ApproxHistogram(rastertable text, rastercolumn text, nband int, sample_percent double precision, bins int, width double precision[] DEFAULT NULL, right boolean DEFAULT FALSE)
	2778
	2779	6. ST_ApproxHistogram(rastertable text, rastercolumn text, nband int, sample_percent double precision, bins int, right boolean)
	2780
	2781	----
	2782	'''ST_Quantile(raster, nband) -> set of records'''[[BR]]
	2783	In addition to determining the histogram of a raster, providing the ability to compute quantiles permits a user to reference a value in the context of the sample or population. Thus, a value could be examined to be at the raster's 25%, 50%, 75% percentile.
	2784
	2785	http://en.wikipedia.org/wiki/Quantile
	2786
	2787	ST_Quantile variations:
	2788
	2789	1. ST_Quantile(rast raster, nband int, exclude_nodata_value boolean, quantiles double precision[]) -> set of records
	2790
	2791	each row returned is of (quantile double precision, value double precision)
	2792
	2793	nband: index of band to process on
	2794
	2795	exclude_nodata_value: if FALSE, nodata values in band are included. if TRUE, nodata values are not included.
	2796
	2797	quantiles: array of percentages to compute values for
	2798
	2799	{{{
	2800	ST_Quantile(rast, 1, FALSE, ARRAY[0.1, 0.3, 0.7])
	2801
	2802	ST_Quantile(rast, 1, TRUE, ARRAY[0.2])
	2803
	2804	ST_Quantile(rast, 1, FALSE, ARRAY[0, 1])
	2805	}}}
	2806
	2807	2. ST_Quantile(rast raster, nband int, quantiles double precision[]) -> set of records
	2808
	2809	"exclude_nodata_value" is assumed to be TRUE
	2810
	2811	{{{
	2812	ST_Quantile(rast, 1, ARRAY[0.1, 0.3, 0.7])
	2813	}}}
	2814
	2815	3. ST_Quantile(rast raster, nband int, exclude_nodata_value boolean) -> set of records
	2816
	2817	"quantiles" assumed to be ARRAY[0, 0.25, 0.5, 0.75, 1]
	2818
	2819	4. ST_Quantile(rast raster, nband int) -> set of records
	2820
	2821	"exclude_nodata_value" is assumed to be TRUE and "quantiles" assumed to be ARRAY[0, 0.25, 0.5, 0.75, 1]
	2822
	2823	5. ST_Quantile(rast raster, quantiles double precision[]) -> set of records
	2824
	2825	"nband" is assumed to be 1 and "exclude_nodata_value" is TRUE
	2826
	2827	6. ST_Quantile(rast raster) -> set of records
	2828
	2829	"nband" is assumed to be 1 and "quantiles" assumed to be ARRAY[0, 0.25, 0.5, 0.75, 1]
	2830
	2831	7. ST_Quantile(rast raster, nband int, exclude_nodata_value boolean, quantile double precision) -> record
	2832
	2833	quantile: the single percentile to compute
	2834
	2835	8. ST_Quantile(rast raster, nband int, quantile double precision) -> record
	2836
	2837	"exclude_nodata_value" is assumed to be TRUE
	2838
	2839	9. ST_Quantile(rast raster, exclude_nodata_value boolean, quantile double precision) -> record
	2840
	2841	"nband" is assumed to be 1
	2842
	2843	10. ST_Quantile(rast raster, quantile double precision) -> record
	2844
	2845	"nband" is assumed to be 1 and "exclude_nodata_value" is assumed to be TRUE
	2846
	2847	ST_ApproxQuantile adds a "sample_percent" indicating the percentage of the raster to sample
	2848
	2849	1. ST_ApproxQuantile(rast raster, nband int, exclude_nodata_value boolean, sample_percent double precision, quantiles double precision[]) -> set of records
	2850
	2851	nband: index of band to process on
	2852
	2853	exclude_nodata_value: if FALSE, nodata values in band are included. if TRUE, nodata values are not included.
	2854
	2855	sample_percent: a value between 0 and 1 indicating the percentage of the raster band's pixels to consider when computing the quantiles
	2856
	2857	quantiles: array of percentages to compute values for
	2858
	2859	{{{
	2860	ST_ApproxQuantile(rast, 1, FALSE, 0.1, ARRAY[0.1, 0.3, 0.7])
	2861
	2862	ST_ApproxQuantile(rast, 1, TRUE, .2, ARRAY[0.2])
	2863
	2864	ST_ApproxQuantile(rast, 1, FALSE, 0.3, ARRAY[0, 1])
	2865	}}}
	2866
	2867	2. ST_ApproxQuantile(rast raster, nband int, sample_percent double precision, quantiles double precision[]) -> set of records
	2868
	2869	"exclude_nodata_value" is assumed to be TRUE
	2870
	2871	{{{
	2872	ST_ApproxQuantile(rast, 1, .05, ARRAY[0.1, 0.3, 0.7])
	2873	}}}
	2874
	2875	3. ST_ApproxQuantile(rast raster, nband int, sample_percent double precision) -> set of records
	2876
	2877	"exclude_nodata_value" is assumed to be TRUE and "quantiles" assumed to be ARRAY[0, 0.25, 0.5, 0.75, 1]
	2878
	2879	4. ST_ApproxQuantile(rast raster, sample_percent double precision, quantiles double precision[]) -> set of records
	2880
	2881	"nband" is assumed to be 1
	2882
	2883	5. ST_ApproxQuantile(rast raster, nband int, sample_percent double precision, quantile double precision) -> record
	2884
	2885	quantile: the single percentile to compute
	2886
	2887	6. ST_ApproxQuantile(rast raster, sample_percent double precision, quantile double precision) -> record
	2888
	2889	"nband" is assumed to be 2
	2890
	2891	7. ST_ApproxQuantile(rast raster, sample_percent double precision) -> set of records
	2892
	2893	"nband" is assumed to be 1 and "quantiles" assumed to be ARRAY[0, 0.25, 0.5, 0.75, 1]
	2894
	2895	8. ST_ApproxQuantile(rast raster, nband int, quantile double precision) -> record
	2896
	2897	"sample_percent" assumed to be 0.1
	2898
	2899	9. ST_ApproxQuantile(rast raster, quantiles double precision[]) -> set of records
	2900
	2901	"nband" is assumed to be 1 and "sample_percent" assumed to be 0.1
	2902
	2903	10. ST_ApproxQuantile(rast raster, quantile double precision) -> record
	2904
	2905	"nband" assumed to be 1 and "sample_percent" assumed to be 0.1
	2906
	2907	11. ST_ApproxQuantile(rast raster, nband int) -> set of records
	2908
	2909	"quantiles" assumed to be ARRAY[0, 0.25, 0.5, 0.75, 1] and "sample_percent" assumed to be 0.1
	2910
	2911	12. ST_ApproxQuantile(rast raster) -> set of records
	2912
	2913	"nband" is assumed to be 1, "quantiles" assumed to be ARRAY[0, 0.25, 0.5, 0.75, 1] and "sample_percent" assumed to be 0.1