| | 1 | {{{ |
| | 2 | #!html |
| | 3 | <div style='background-color: #F4F4F4; border: 1px solid gray; width:400px;' > |
| | 4 | <br> |
| | 5 | <UL> |
| | 6 | <LI><A href=http://trac.osgeo.org/postgis/wiki/PostGIS_Raster_SoC_Idea_2012/Distance_Analysis_Tools/code#EuclideanDistance>Euclidean Distance</A></LI> |
| | 7 | <LI><A href=http://trac.osgeo.org/postgis/wiki/PostGIS_Raster_SoC_Idea_2012/Distance_Analysis_Tools/code#CostDistance>Cost Distance</A></LI> |
| | 8 | </UL> |
| | 9 | <br> |
| | 10 | </div> |
| | 11 | }}} |
| | 12 | |
| | 13 | == Euclidean Distance == |
| | 14 | |
| | 15 | '''ST_EuclideanDistance()''' |
| | 16 | |
| | 17 | {{{ |
| | 18 | #!sql |
| | 19 | -------------------------------------------------------------------- |
| | 20 | -- ST_EuclideanDistance - (for one raster) Return a raster generated from |
| | 21 | -- a set of raster specifications, which values are |
| | 22 | -- the Euclidean distance from pixel to the points |
| | 23 | -- (for now only concerning point geometries) |
| | 24 | -- from the input source table of geometries |
| | 25 | -- (points for now, lines or polygons in the future). |
| | 26 | -- Arguments |
| | 27 | -- width,height,rastulx,rastuly,rastscalex,rastscaley,rastskewx,rastskewy |
| | 28 | -- - Dimenssions and georeference of resulted raster. |
| | 29 | -- rastsrid - SRID of the resulted raster |
| | 30 | -- rastndv - Nodata value for resulted raster |
| | 31 | -- pixeltype text - Pixeltype assigned to the resulting raster. By default |
| | 32 | -- to be the pixeltype of the reference raster if not specified. |
| | 33 | -- sourceschema text - Database schema of the source geometry table. |
| | 34 | -- sourcetable text - Source geometry table name. |
| | 35 | -- sourcegeomcolumn text - Source geometry table geometry column name. |
| | 36 | -- maxdist double precision - Maximum distance from pixel to the source |
| | 37 | -- when the source is too far from the pixel. |
| | 38 | -- Pixel that exceeds it will be assigned nodatavalue. |
| | 39 | -------------------------------------------------------------------- |
| | 40 | DROP FUNCTION IF EXISTS ST_EuclideanDistance(width integer, |
| | 41 | height integer, |
| | 42 | rastulx float8, |
| | 43 | rastuly float8, |
| | 44 | rastscalex float8, |
| | 45 | rastscaley float8, |
| | 46 | rastskewx float8, |
| | 47 | rastskewy float8, |
| | 48 | rastsrid integer, |
| | 49 | rastndv float8, |
| | 50 | pixeltype text, |
| | 51 | sourceschema text, |
| | 52 | sourcetable text, |
| | 53 | sourcegeomcolumn text, |
| | 54 | double precision = -1); |
| | 55 | CREATE OR REPLACE FUNCTION ST_EuclideanDistance(width integer, |
| | 56 | height integer, |
| | 57 | rastulx float8, |
| | 58 | rastuly float8, |
| | 59 | rastscalex float8, |
| | 60 | rastscaley float8, |
| | 61 | rastskewx float8, |
| | 62 | rastskewy float8, |
| | 63 | rastsrid integer, |
| | 64 | rastndv float8, |
| | 65 | pixeltype text, |
| | 66 | sourceschema text, |
| | 67 | sourcetable text, |
| | 68 | sourcegeomcolumn text, |
| | 69 | double precision = -1) |
| | 70 | RETURNS raster AS |
| | 71 | $$ |
| | 72 | DECLARE |
| | 73 | maxdist ALIAS FOR $15; |
| | 74 | x integer; |
| | 75 | y integer; |
| | 76 | sourcex float8; |
| | 77 | sourcey float8; |
| | 78 | sourcexr integer; |
| | 79 | sourceyr integer; |
| | 80 | sourcesrid integer; |
| | 81 | newx float8; |
| | 82 | newy float8; |
| | 83 | exesql text; |
| | 84 | newnodatavalue float8; |
| | 85 | newinitialvalue float8; |
| | 86 | newrast raster; |
| | 87 | newval float8; |
| | 88 | newpixeltype text; |
| | 89 | -- Assuming reference raster has only one band |
| | 90 | band integer := 1; |
| | 91 | geom geometry; |
| | 92 | BEGIN |
| | 93 | -- Assuming source point table has one SRID for all geometries |
| | 94 | EXECUTE 'SELECT DISTINCT ST_SRID(' || sourcegeomcolumn || ') FROM ' || sourceschema || '.' || sourcetable || ';' INTO sourcesrid; |
| | 95 | |
| | 96 | -- Create a new empty raster using provided georeference |
| | 97 | newrast := ST_MakeEmptyRaster(width, height, rastulx, rastuly, rastscalex,rastscaley, rastskewx, rastskewy, rastsrid); |
| | 98 | |
| | 99 | -- Check if the new raster is empty (width = 0 OR height = 0) |
| | 100 | IF ST_IsEmpty(newrast) THEN |
| | 101 | RAISE NOTICE 'ST_EuclideanDistance: Raster is empty. Returning an empty raster'; |
| | 102 | RETURN newrast; |
| | 103 | END IF; |
| | 104 | |
| | 105 | -- Set the new pixeltype |
| | 106 | newpixeltype := pixeltype; |
| | 107 | IF newpixeltype != '1BB' AND newpixeltype != '2BUI' AND newpixeltype != '4BUI' AND newpixeltype != '8BSI' AND newpixeltype != '8BUI' AND |
| | 108 | newpixeltype != '16BSI' AND newpixeltype != '16BUI' AND newpixeltype != '32BSI' AND newpixeltype != '32BUI' AND newpixeltype != '32BF' AND newpixeltype != '64BF' THEN |
| | 109 | RAISE EXCEPTION 'ST_EuclideanDistance: Invalid pixeltype "%". Aborting.', newpixeltype; |
| | 110 | END IF; |
| | 111 | |
| | 112 | -- Check for notada value |
| | 113 | newnodatavalue := rastndv; |
| | 114 | IF newnodatavalue IS NULL OR newnodatavalue < ST_MinPossibleValue(newpixeltype) OR newnodatavalue > (-ST_MinPossibleValue(newpixeltype) - 1) THEN |
| | 115 | RAISE NOTICE 'ST_EuclideanDistance: Reference raster do not have a nodata value or is out of range for the new raster pixeltype, nodata value for new raster set to the min value possible'; |
| | 116 | newnodatavalue := ST_MinPossibleValue(newpixeltype); |
| | 117 | END IF; |
| | 118 | -- We set the initial value of the resulting raster to nodata value. |
| | 119 | -- If nodatavalue is null then the raster will be initialise to ST_MinPossibleValue |
| | 120 | newinitialvalue := newnodatavalue; |
| | 121 | |
| | 122 | -- Create the raster receiving all the computed distance values. Initialize it to the new initial value. |
| | 123 | newrast := ST_AddBand(newrast, newpixeltype, newinitialvalue, newnodatavalue); |
| | 124 | |
| | 125 | -- Set raster pixel value to zero if pixel is source point |
| | 126 | exesql := 'SELECT ' || sourcegeomcolumn || ' FROM ' || sourceschema || '.' || sourcetable || ';'; |
| | 127 | FOR geom IN EXECUTE(exesql) LOOP |
| | 128 | sourcex := ST_X(geom); |
| | 129 | sourcey := ST_Y(geom); |
| | 130 | sourcexr := ST_World2RasterCoordX(newrast, sourcex, sourcey); |
| | 131 | sourceyr := ST_World2RasterCoordY(newrast, sourcex, sourcey); |
| | 132 | -- If source point within raster range, then set pixel value to zero |
| | 133 | IF sourcexr <= width AND sourceyr <= height THEN |
| | 134 | newrast := ST_SetValue(newrast, band, sourcexr, sourceyr, 0); |
| | 135 | END IF; |
| | 136 | END LOOP; |
| | 137 | |
| | 138 | -- Scan pixels in the raster set pixel value to the computed Eculidean distance |
| | 139 | -- to its nearest source point. |
| | 140 | -- There is place for optimization here for a more efficient scanning method |
| | 141 | FOR x IN 1..width LOOP |
| | 142 | FOR y IN 1..height LOOP |
| | 143 | newx := ST_Raster2WorldCoordX(newrast, x, y); |
| | 144 | newy := ST_Raster2WorldCoordY(newrast, x, y); |
| | 145 | -- If pixel is not the source point then compute Eculidean distance |
| | 146 | IF ST_Value(newrast, band, x, y) != 0 OR ST_Value(newrast, band, x, y) IS NULL THEN |
| | 147 | exesql := 'SELECT ST_Distance(ST_SetSRID(ST_MakePoint(' || newx || ',' || newy || '),' || sourcesrid || '), (SELECT ' || sourcegeomcolumn || ' FROM ' || sourceschema || '.' || sourcetable || ' ORDER BY ' || sourcegeomcolumn || ' <-> ST_SetSRID(ST_MakePoint(' || newx || ',' || newy || '),' || sourcesrid || ') LIMIT 1));'; |
| | 148 | EXECUTE exesql INTO newval; |
| | 149 | -- If max distance specified |
| | 150 | IF maxdist != -1 THEN |
| | 151 | -- Any distance exceeds max distance is assigned nodata value |
| | 152 | IF newval > maxdist THEN |
| | 153 | newval = newnodatavalue; |
| | 154 | END IF; |
| | 155 | END IF; |
| | 156 | END IF; |
| | 157 | newrast := ST_SetValue(newrast, band, x, y, newval); |
| | 158 | END LOOP; |
| | 159 | END LOOP; |
| | 160 | |
| | 161 | RETURN newrast; |
| | 162 | END; |
| | 163 | $$ |
| | 164 | LANGUAGE 'plpgsql'; |
| | 165 | |
| | 166 | -- test |
| | 167 | -- CREATE TABLE test_eudist_2 AS (SELECT 1 AS rid,ST_EuclideanDistance(10, 10, 0, 0, 9, 9, 0, 0, 4326,-1,'32BF','public','test_geom','the_geom') AS rast FROM test_raster); |
| | 168 | -- CREATE TABLE test_eudist_22 AS (SELECT 1 AS rid,ST_EuclideanDistance(10, 10, 0, 0, 9, 9, 0, 0, 4326,-1,'32BF','public','test_geom','the_geom',4954880) AS rast FROM test_raster); |
| | 169 | |
| | 170 | |
| | 171 | -------------------------------------------------------------------- |
| | 172 | -- ST_EuclideanDistance - (for one raster) Return a raster generated |
| | 173 | -- from a one band reference raster, |
| | 174 | -- which values are the Euclidean distance |
| | 175 | -- from pixel to the points |
| | 176 | -- (for now only concerning point geometries) |
| | 177 | -- from the input source table of geometries |
| | 178 | -- (points for now, lines or polygons in the future). |
| | 179 | -- Arguments |
| | 180 | -- refrast raster - Reference raster align with which Euclidean distance |
| | 181 | -- raster will be created. |
| | 182 | -- pixeltype text - Pixeltype assigned to the resulting raster. By default |
| | 183 | -- to be the pixeltype of the reference raster if not specified. |
| | 184 | -- sourceschema text - Database schema of the source geometry table. |
| | 185 | -- sourcetable text - Source geometry table name. |
| | 186 | -- sourcegeomcolumn text - Source geometry table geometry column name. |
| | 187 | -- maxdist double precision - Maximum distance from pixel to the source |
| | 188 | -- when the source is too far from the pixel. |
| | 189 | -- Pixel that exceeds it will be assigned nodatavalue. |
| | 190 | -------------------------------------------------------------------- |
| | 191 | DROP FUNCTION IF EXISTS ST_EuclideanDistance(refrast raster, |
| | 192 | pixeltype text, |
| | 193 | sourceschema text, |
| | 194 | sourcetable text, |
| | 195 | sourcegeomcolumn text, |
| | 196 | double precision = -1); |
| | 197 | CREATE OR REPLACE FUNCTION ST_EuclideanDistance(refrast raster, |
| | 198 | pixeltype text, |
| | 199 | sourceschema text, |
| | 200 | sourcetable text, |
| | 201 | sourcegeomcolumn text, |
| | 202 | double precision = -1) |
| | 203 | RETURNS raster AS |
| | 204 | $$ |
| | 205 | DECLARE |
| | 206 | maxdist ALIAS FOR $6; |
| | 207 | width integer; |
| | 208 | height integer; |
| | 209 | x integer; |
| | 210 | y integer; |
| | 211 | sourcex float8; |
| | 212 | sourcey float8; |
| | 213 | sourcexr integer; |
| | 214 | sourceyr integer; |
| | 215 | sourcesrid integer; |
| | 216 | newsrid integer; |
| | 217 | newx float8; |
| | 218 | newy float8; |
| | 219 | exesql text; |
| | 220 | newnodatavalue float8; |
| | 221 | newinitialvalue float8; |
| | 222 | newrast raster; |
| | 223 | newval float8; |
| | 224 | newpixeltype text; |
| | 225 | -- Assuming reference raster has only one band |
| | 226 | band integer := 1; |
| | 227 | geom geometry; |
| | 228 | BEGIN |
| | 229 | -- Check if reference raster is NULL |
| | 230 | IF refrast IS NULL THEN |
| | 231 | RAISE NOTICE 'ST_EuclideanDistance: Reference raster is NULL. Returning NULL'; |
| | 232 | RETURN NULL; |
| | 233 | END IF; |
| | 234 | |
| | 235 | width := ST_Width(refrast); |
| | 236 | height := ST_Height(refrast); |
| | 237 | newsrid := ST_SRID(refrast); |
| | 238 | -- Assuming source point table has one SRID for all geometries |
| | 239 | EXECUTE 'SELECT DISTINCT ST_SRID(' || sourcegeomcolumn || ') FROM ' || sourceschema || '.' || sourcetable || ';' INTO sourcesrid; |
| | 240 | |
| | 241 | -- Create a new empty raster having the same georeference as the reference raster |
| | 242 | newrast := ST_MakeEmptyRaster(width, height, ST_UpperLeftX(refrast), ST_UpperLeftY(refrast), ST_ScaleX(refrast), ST_ScaleY(refrast), ST_SkewX(refrast), ST_SkewY(refrast), newsrid); |
| | 243 | |
| | 244 | -- Check if the new raster is empty (width = 0 OR height = 0) |
| | 245 | IF ST_IsEmpty(newrast) THEN |
| | 246 | RAISE NOTICE 'ST_EuclideanDistance: Raster is empty. Returning an empty raster'; |
| | 247 | RETURN newrast; |
| | 248 | END IF; |
| | 249 | |
| | 250 | -- Set the new pixeltype |
| | 251 | newpixeltype := pixeltype; |
| | 252 | -- If pixeltype not specified then use the pixeltype of the reference raster |
| | 253 | IF newpixeltype IS NULL THEN |
| | 254 | newpixeltype := ST_BandPixelType(refrast, band); |
| | 255 | ELSIF newpixeltype != '1BB' AND newpixeltype != '2BUI' AND newpixeltype != '4BUI' AND newpixeltype != '8BSI' AND newpixeltype != '8BUI' AND |
| | 256 | newpixeltype != '16BSI' AND newpixeltype != '16BUI' AND newpixeltype != '32BSI' AND newpixeltype != '32BUI' AND newpixeltype != '32BF' AND newpixeltype != '64BF' THEN |
| | 257 | RAISE EXCEPTION 'ST_EuclideanDistance: Invalid pixeltype "%". Aborting.', newpixeltype; |
| | 258 | END IF; |
| | 259 | |
| | 260 | -- Check for notada value |
| | 261 | newnodatavalue := ST_BandNodataValue(refrast, band); |
| | 262 | IF newnodatavalue IS NULL OR newnodatavalue < ST_MinPossibleValue(newpixeltype) OR newnodatavalue > (-ST_MinPossibleValue(newpixeltype) - 1) THEN |
| | 263 | RAISE NOTICE 'ST_EuclideanDistance: Reference raster do not have a nodata value or is out of range for the new raster pixeltype, nodata value for new raster set to the min value possible'; |
| | 264 | newnodatavalue := ST_MinPossibleValue(newpixeltype); |
| | 265 | END IF; |
| | 266 | -- We set the initial value of the resulting raster to nodata value. |
| | 267 | -- If nodatavalue is null then the raster will be initialise to ST_MinPossibleValue |
| | 268 | newinitialvalue := newnodatavalue; |
| | 269 | |
| | 270 | -- Create the raster receiving all the computed distance values. Initialize it to the new initial value. |
| | 271 | newrast := ST_AddBand(newrast, newpixeltype, newinitialvalue, newnodatavalue); |
| | 272 | |
| | 273 | -- Set raster pixel value to zero if pixel is source point |
| | 274 | exesql := 'SELECT ' || sourcegeomcolumn || ' FROM ' || sourceschema || '.' || sourcetable || ';'; |
| | 275 | FOR geom IN EXECUTE(exesql) LOOP |
| | 276 | sourcex := ST_X(geom); |
| | 277 | sourcey := ST_Y(geom); |
| | 278 | sourcexr := ST_World2RasterCoordX(newrast, sourcex, sourcey); |
| | 279 | sourceyr := ST_World2RasterCoordY(newrast, sourcex, sourcey); |
| | 280 | -- If source point within raster range, then set pixel value to zero |
| | 281 | IF sourcexr <= width AND sourceyr <= height THEN |
| | 282 | newrast := ST_SetValue(newrast, band, sourcexr, sourceyr, 0); |
| | 283 | END IF; |
| | 284 | END LOOP; |
| | 285 | |
| | 286 | -- Scan pixels in the raster set pixel value to the computed Eculidean distance |
| | 287 | -- to its nearest source point. |
| | 288 | -- There is place for optimization here for a more efficient scanning method |
| | 289 | FOR x IN 1..width LOOP |
| | 290 | FOR y IN 1..height LOOP |
| | 291 | newx := ST_Raster2WorldCoordX(newrast, x, y); |
| | 292 | newy := ST_Raster2WorldCoordY(newrast, x, y); |
| | 293 | -- If pixel is not the source point then compute Eculidean distance |
| | 294 | IF ST_Value(newrast, band, x, y) != 0 OR ST_Value(newrast, band, x, y) IS NULL THEN |
| | 295 | exesql := 'SELECT ST_Distance(ST_SetSRID(ST_MakePoint(' || newx || ',' || newy || '),' || sourcesrid || '), (SELECT ' || sourcegeomcolumn || ' FROM ' || sourceschema || '.' || sourcetable || ' ORDER BY ' || sourcegeomcolumn || ' <-> ST_SetSRID(ST_MakePoint(' || newx || ',' || newy || '),' || sourcesrid || ') LIMIT 1));'; |
| | 296 | EXECUTE exesql INTO newval; |
| | 297 | -- If max distance specified |
| | 298 | IF maxdist != -1 THEN |
| | 299 | -- Any distance exceeds max distance is assigned nodata value |
| | 300 | IF newval > maxdist THEN |
| | 301 | newval := newnodatavalue; |
| | 302 | END IF; |
| | 303 | END IF; |
| | 304 | END IF; |
| | 305 | newrast := ST_SetValue(newrast, band, x, y, newval); |
| | 306 | END LOOP; |
| | 307 | END LOOP; |
| | 308 | |
| | 309 | RETURN newrast; |
| | 310 | END; |
| | 311 | $$ |
| | 312 | LANGUAGE 'plpgsql'; |
| | 313 | |
| | 314 | -- test |
| | 315 | -- CREATE TABLE test_eudist AS (SELECT 1 AS rid,ST_EuclideanDistance(rast,NULL,'public','test_geom','the_geom') AS rast FROM test_raster); |
| | 316 | -- CREATE TABLE test_eudist2 AS (SELECT 1 AS rid,ST_EuclideanDistance(rast,NULL,'public','test_geom','the_geom',4954880) AS rast FROM test_raster); |
| | 317 | }}} |
| | 318 | |
| | 319 | |
| | 320 | == Cost Distance == |
| | 321 | |
| | 322 | '''ST_CostDistance()''' |
| | 323 | |
| | 324 | {{{ |
| | 325 | #!sql |
| | 326 | -------------------------------------------------------------------- |
| | 327 | -- ST_CostDistance - Return a raster generated from a one band reference |
| | 328 | -- raster a table and a one band cost raster, which values |
| | 329 | -- are the the least accumulative cost of traversing |
| | 330 | -- the cost surface from source points to each cell. |
| | 331 | -- (points for now, lines or polygons in the future). |
| | 332 | -- Arguments |
| | 333 | -- refrast raster - Reference raster align with which cost distance |
| | 334 | -- raster will be created. |
| | 335 | -- pixeltype text - Pixeltype assigned to the resulting raster. By default |
| | 336 | -- to be the pixeltype of the reference raster if not specified. |
| | 337 | -- costrast raster - Cost raster in which each cell value represents the |
| | 338 | -- cost of traversing this cell. |
| | 339 | -- sourceschema text - Database schema of the source geometry table. |
| | 340 | -- sourcetable text - Source geometry table name. |
| | 341 | -- sourcegeomcolumn text - Source geometry table geometry column name. |
| | 342 | -- maxdist double precision - Maximum distance from pixel to the source |
| | 343 | -- when the source is too far from the pixel. |
| | 344 | -- Pixel that exceeds it will be assigned nodatavalue. |
| | 345 | -------------------------------------------------------------------- |
| | 346 | -- Create array type which stores the column, row, and cost value of each pixel in the iteration. |
| | 347 | CREATE TYPE p_node AS (id integer,x integer,y integer,val float8); |
| | 348 | |
| | 349 | -- Function to get a set of elements from an array |
| | 350 | DROP FUNCTION IF EXISTS explode_array(p_node[]); |
| | 351 | CREATE OR REPLACE FUNCTION explode_array(p_node[]) |
| | 352 | RETURNS SETOF p_node AS |
| | 353 | $$ |
| | 354 | SELECT $1[i] FROM GENERATE_SERIES(1,ARRAY_UPPER($1,1)) AS i; |
| | 355 | $$ |
| | 356 | LANGUAGE 'sql' IMMUTABLE; |
| | 357 | |
| | 358 | DROP FUNCTION IF EXISTS ST_CostDistance(refrast raster, |
| | 359 | pixeltype text, |
| | 360 | costrast raster, |
| | 361 | sourceschema text, |
| | 362 | sourcetable text, |
| | 363 | sourcegeomcolumn text, |
| | 364 | double precision = -1); |
| | 365 | CREATE OR REPLACE FUNCTION ST_CostDistance(refrast raster, |
| | 366 | pixeltype text, |
| | 367 | costrast raster, |
| | 368 | sourceschema text, |
| | 369 | sourcetable text, |
| | 370 | sourcegeomcolumn text, |
| | 371 | double precision = -1) |
| | 372 | RETURNS raster AS |
| | 373 | $$ |
| | 374 | DECLARE |
| | 375 | maxdist ALIAS FOR $7; |
| | 376 | newrast raster; |
| | 377 | newwidth integer; |
| | 378 | newheight integer; |
| | 379 | newsrid integer; |
| | 380 | newpixeltype text; |
| | 381 | newnodatavalue float8; |
| | 382 | newinitialvalue float8; |
| | 383 | |
| | 384 | x integer; |
| | 385 | y integer; |
| | 386 | sourcex float8; |
| | 387 | sourcey float8; |
| | 388 | sourcexr integer; |
| | 389 | sourceyr integer; |
| | 390 | sourcesrid integer; |
| | 391 | sourceboxgeom geometry; |
| | 392 | |
| | 393 | costarray p_node[] = '{}'; |
| | 394 | node p_node; |
| | 395 | costval float8; |
| | 396 | |
| | 397 | -- Assuming reference raster has only one band |
| | 398 | band integer := 1; |
| | 399 | |
| | 400 | nx integer; |
| | 401 | ny integer; |
| | 402 | ncoordx float8; |
| | 403 | ncoordy float8; |
| | 404 | ncostval float8; |
| | 405 | nnewcostval float8; |
| | 406 | ncostrastx integer; |
| | 407 | ncostrasty integer; |
| | 408 | ncostrastval float8; |
| | 409 | |
| | 410 | arrayid integer := 0; |
| | 411 | tempnode p_node[]; |
| | 412 | minval float8; |
| | 413 | minnodeid int; |
| | 414 | exesql text; |
| | 415 | geom geometry; |
| | 416 | flag boolean := False; |
| | 417 | BEGIN |
| | 418 | -- Check if reference raster is NULL |
| | 419 | IF refrast IS NULL THEN |
| | 420 | RAISE NOTICE 'ST_CostDistance: Reference raster is NULL. Returning NULL'; |
| | 421 | RETURN NULL; |
| | 422 | END IF; |
| | 423 | |
| | 424 | -- Check if cost raster is NULL |
| | 425 | IF costrast IS NULL THEN |
| | 426 | RAISE NOTICE 'ST_CostDistance: Cost raster is NULL. Returning NULL'; |
| | 427 | RETURN NULL; |
| | 428 | END IF; |
| | 429 | |
| | 430 | newwidth := ST_Width(refrast); |
| | 431 | newheight := ST_Height(refrast); |
| | 432 | newsrid := ST_SRID(refrast); |
| | 433 | |
| | 434 | -- Assuming source point table has one SRID for all geometries |
| | 435 | EXECUTE 'SELECT DISTINCT ST_SRID(' || sourcegeomcolumn || ') FROM ' || sourceschema || '.' || sourcetable || ';' INTO sourcesrid; |
| | 436 | |
| | 437 | -- Create a new empty raster having the same georeference as the reference raster |
| | 438 | newrast := ST_MakeEmptyRaster(newwidth, newheight, ST_UpperLeftX(refrast), ST_UpperLeftY(refrast), ST_ScaleX(refrast), ST_ScaleY(refrast), ST_SkewX(refrast), ST_SkewY(refrast), newsrid); |
| | 439 | |
| | 440 | -- Check if the new raster is empty (width = 0 OR height = 0) |
| | 441 | IF ST_IsEmpty(newrast) THEN |
| | 442 | RAISE NOTICE 'ST_CostDistance: Raster is empty. Returning an empty raster'; |
| | 443 | RETURN newrast; |
| | 444 | END IF; |
| | 445 | |
| | 446 | -- Set the new pixeltype |
| | 447 | newpixeltype := pixeltype; |
| | 448 | -- If pixeltype not specified then use the pixeltype of the reference raster |
| | 449 | IF newpixeltype IS NULL THEN |
| | 450 | newpixeltype := ST_BandPixelType(refrast, band); |
| | 451 | ELSIF newpixeltype != '1BB' AND newpixeltype != '2BUI' AND newpixeltype != '4BUI' AND newpixeltype != '8BSI' AND newpixeltype != '8BUI' AND |
| | 452 | newpixeltype != '16BSI' AND newpixeltype != '16BUI' AND newpixeltype != '32BSI' AND newpixeltype != '32BUI' AND newpixeltype != '32BF' AND newpixeltype != '64BF' THEN |
| | 453 | RAISE EXCEPTION 'ST_CostDistance: Invalid pixeltype "%". Aborting.', newpixeltype; |
| | 454 | END IF; |
| | 455 | |
| | 456 | -- Check for notada value |
| | 457 | newnodatavalue := ST_BandNodataValue(refrast, band); |
| | 458 | IF newnodatavalue IS NULL OR newnodatavalue < ST_MinPossibleValue(newpixeltype) OR newnodatavalue > (-ST_MinPossibleValue(newpixeltype) - 1) THEN |
| | 459 | RAISE NOTICE 'ST_CostDistance: Reference raster do not have a nodata value or is out of range for the new raster pixeltype, nodata value for new raster set to the min value possible'; |
| | 460 | newnodatavalue := ST_MinPossibleValue(newpixeltype); |
| | 461 | END IF; |
| | 462 | -- We set the initial value of the resulting raster to nodata value. |
| | 463 | -- If nodatavalue is null then the raster will be initialise to ST_MinPossibleValue |
| | 464 | newinitialvalue := newnodatavalue; |
| | 465 | |
| | 466 | -- Create the raster receiving all the computed cost distance values. Initialize it to the new initial value. |
| | 467 | newrast := ST_AddBand(newrast, newpixeltype, newinitialvalue, newnodatavalue); |
| | 468 | |
| | 469 | -- Check if source points boundary intersects with extent of cost raster, if not, return new raster initiated with no data value. |
| | 470 | exesql := 'SELECT ST_CONVEXHULL(ST_COLLECT(' || sourcegeomcolumn || ')) FROM ' || sourceschema || '.' || sourcetable || ';'; |
| | 471 | EXECUTE exesql INTO sourceboxgeom; |
| | 472 | SELECT ST_Intersects(costrast,sourceboxgeom) INTO flag; |
| | 473 | IF NOT flag THEN |
| | 474 | RAISE NOTICE 'ST_CostDistance: Source points are out side of the cost raster. Returning raster with no data values.'; |
| | 475 | RETURN newrast; |
| | 476 | END IF; |
| | 477 | |
| | 478 | -- Set raster pixel value to nodatavalue or zero if pixel is source point; |
| | 479 | -- Initialize cost_array with source points that are within the extent of cost raster. |
| | 480 | exesql := 'SELECT ' || sourcegeomcolumn || ' FROM ' || sourceschema || '.' || sourcetable || ';'; |
| | 481 | FOR geom IN EXECUTE(exesql) LOOP |
| | 482 | sourcex := ST_X(geom); |
| | 483 | sourcey := ST_Y(geom); |
| | 484 | sourcexr := ST_World2RasterCoordX(newrast, sourcex, sourcey); |
| | 485 | sourceyr := ST_World2RasterCoordY(newrast, sourcex, sourcey); |
| | 486 | -- If source point within new raster extent |
| | 487 | IF sourcexr <= width AND sourceyr <= height THEN |
| | 488 | -- If source point within cost raster extent, set new raster pixel value to zero |
| | 489 | -- since there is no accumulative cost to return to itself; |
| | 490 | -- Add source point to cost array. |
| | 491 | IF ST_Within(ST_SetSRID(ST_MakePoint(sourcex,sourcey),ST_SRID(costrast)),ST_Envelope(costrast)) THEN |
| | 492 | newrast := ST_SetValue(newrast, band, sourcexr, sourceyr, 0); |
| | 493 | arrayid := arrayid + 1; |
| | 494 | node.id := arrayid; |
| | 495 | node.x := sourcexr; |
| | 496 | node.y := sourceyr; |
| | 497 | node.val := costval; |
| | 498 | costarray := ARRAY_APPEND(costarray,node); |
| | 499 | END IF; |
| | 500 | END IF; |
| | 501 | END LOOP; |
| | 502 | |
| | 503 | -- Loop through the cost array, pop up node with least accumulative cost value; |
| | 504 | -- Calculate cost values for its neighbors (8 directions); |
| | 505 | flag := True; |
| | 506 | WHILE flag LOOP |
| | 507 | -- End loop when cost values in the cost array are all NULL |
| | 508 | SELECT ARRAY_AGG(cv) FROM (SELECT DISTINCT explode_array(costarray) AS cv) AS foo INTO tempnode; |
| | 509 | IF ARRAY_LENGTH(tempnode,1) = 1 AND tempnode[1] = NULL THEN |
| | 510 | flag := False; |
| | 511 | ELSE |
| | 512 | SELECT MIN(costarray[i].val) FROM GENERATE_SERIES(1,ARRAY_UPPER(costarray,1)) AS i INTO minval; |
| | 513 | SELECT costarray[i].id FROM GENERATE_SERIES(1,ARRAY_UPPER(costarray,1)) AS i WHERE costarray[i].val = minval INTO minnodeid; |
| | 514 | -- Pop up node with min cost value, set its val in the array to be NULL |
| | 515 | x := costarray[minnodeid].x; |
| | 516 | y := costarray[minnodeid].y; |
| | 517 | costval := ST_Value(newrast,band,x,y); |
| | 518 | costarray[minnodeid] := NULL; |
| | 519 | -- Calculate cost distance for neighbors in perpendicular directions |
| | 520 | -- neighbor(x,y+1) |
| | 521 | nx := x; |
| | 522 | ny := y+1; |
| | 523 | IF ny <= newheight THEN |
| | 524 | ncoordx := ST_Raster2WorldCoordX(newrast, x, y); |
| | 525 | ncoordy := ST_Raster2WorldCoordY(newrast, x, y); |
| | 526 | IF ST_Within(ST_SetSRID(ST_MakePoint(ncoordx,ncoordy),ST_SRID(costrast)),ST_Envelope(costrast)) THEN |
| | 527 | ncostrastx := ST_World2RasterCoordX(costrast,ncoordx,ncoordy); |
| | 528 | ncostrasty := ST_World2RasterCoordY(costrast,ncoordx,ncoordy); |
| | 529 | ncostrastval := ST_Value(costrast,band,ncostrastx,ncostrasty); |
| | 530 | nnewcostval := (costval + ncostrastval)/2; |
| | 531 | ncostval := ST_Value(newrast,band,nx,ny); |
| | 532 | IF ncostval <> newnodatavalue THEN |
| | 533 | IF nnewcostval < ncostval THEN |
| | 534 | ncostval := nnewcostval; |
| | 535 | arrayid := arrayid + 1; |
| | 536 | node.id := arrayid; |
| | 537 | node.x := nx; |
| | 538 | node.y := ny; |
| | 539 | node.val := ncostval; |
| | 540 | costarray := ARRAY_APPEND(costarray,node); |
| | 541 | newrast := ST_SetValue(newrast, band, nx, ny, ncostval); |
| | 542 | END IF; |
| | 543 | END IF; |
| | 544 | ELSE |
| | 545 | newrast := ST_SetValue(newrast, band, nx, ny, newnodatavalue); |
| | 546 | END IF; |
| | 547 | END IF; |
| | 548 | |
| | 549 | -- neighbor(x,y-1) |
| | 550 | nx := x; |
| | 551 | ny := y-1; |
| | 552 | IF ny >= 1 THEN |
| | 553 | ncoordx := ST_Raster2WorldCoordX(newrast, x, y); |
| | 554 | ncoordy := ST_Raster2WorldCoordY(newrast, x, y); |
| | 555 | IF ST_Within(ST_SetSRID(ST_MakePoint(ncoordx,ncoordy),ST_SRID(costrast)),ST_Envelope(costrast)) THEN |
| | 556 | ncostrastx := ST_World2RasterCoordX(costrast,ncoordx,ncoordy); |
| | 557 | ncostrasty := ST_World2RasterCoordY(costrast,ncoordx,ncoordy); |
| | 558 | ncostrastval := ST_Value(costrast,band,ncostrastx,ncostrasty); |
| | 559 | nnewcostval := (costval + ncostrastval)/2; |
| | 560 | ncostval := ST_Value(newrast,band,nx,ny); |
| | 561 | IF ncostval <> newnodatavalue THEN |
| | 562 | IF nnewcostval < ncostval THEN |
| | 563 | -- If max distance specified |
| | 564 | IF maxdist != -1 THEN |
| | 565 | -- Any distance exceeds max distance is assigned nodata value |
| | 566 | IF nnewcostval > maxdist THEN |
| | 567 | nnewcostval := newnodatavalue; |
| | 568 | newrast := ST_SetValue(newrast, band, nx, ny, newnodatavalue); |
| | 569 | END IF; |
| | 570 | END IF; |
| | 571 | if nnewcostval <> newnodatavalue THEN |
| | 572 | ncostval := nnewcostval; |
| | 573 | arrayid := arrayid + 1; |
| | 574 | node.id := arrayid; |
| | 575 | node.x := nx; |
| | 576 | node.y := ny; |
| | 577 | node.val := ncostval; |
| | 578 | costarray := ARRAY_APPEND(costarray,node); |
| | 579 | newrast := ST_SetValue(newrast, band, nx, ny, ncostval); |
| | 580 | END IF; |
| | 581 | END IF; |
| | 582 | END IF; |
| | 583 | ELSE |
| | 584 | newrast := ST_SetValue(newrast, band, nx, ny, newnodatavalue); |
| | 585 | END IF; |
| | 586 | END IF; |
| | 587 | |
| | 588 | -- neighbor(x+1,y) |
| | 589 | nx := x+1; |
| | 590 | ny := y; |
| | 591 | IF nx <= newwidth THEN |
| | 592 | ncoordx := ST_Raster2WorldCoordX(newrast, x, y); |
| | 593 | ncoordy := ST_Raster2WorldCoordY(newrast, x, y); |
| | 594 | IF ST_Within(ST_SetSRID(ST_MakePoint(ncoordx,ncoordy),ST_SRID(costrast)),ST_Envelope(costrast)) THEN |
| | 595 | ncostrastx := ST_World2RasterCoordX(costrast,ncoordx,ncoordy); |
| | 596 | ncostrasty := ST_World2RasterCoordY(costrast,ncoordx,ncoordy); |
| | 597 | ncostrastval := ST_Value(costrast,band,ncostrastx,ncostrasty); |
| | 598 | nnewcostval := (costval + ncostrastval)/2; |
| | 599 | ncostval := ST_Value(newrast,band,nx,ny); |
| | 600 | IF ncostval <> newnodatavalue THEN |
| | 601 | IF nnewcostval < ncostval THEN |
| | 602 | ncostval := nnewcostval; |
| | 603 | arrayid := arrayid + 1; |
| | 604 | node.id := arrayid; |
| | 605 | node.x := nx; |
| | 606 | node.y := ny; |
| | 607 | node.val := ncostval; |
| | 608 | costarray := ARRAY_APPEND(costarray,node); |
| | 609 | newrast := ST_SetValue(newrast, band, nx, ny, ncostval); |
| | 610 | END IF; |
| | 611 | END IF; |
| | 612 | ELSE |
| | 613 | newrast := ST_SetValue(newrast, band, nx, ny, newnodatavalue); |
| | 614 | END IF; |
| | 615 | END IF; |
| | 616 | |
| | 617 | -- neighbor(x-1,y) |
| | 618 | nx := x-1; |
| | 619 | ny := y; |
| | 620 | IF nx >= 1 THEN |
| | 621 | ncoordx := ST_Raster2WorldCoordX(newrast, x, y); |
| | 622 | ncoordy := ST_Raster2WorldCoordY(newrast, x, y); |
| | 623 | IF ST_Within(ST_SetSRID(ST_MakePoint(ncoordx,ncoordy),ST_SRID(costrast)),ST_Envelope(costrast)) THEN |
| | 624 | ncostrastx := ST_World2RasterCoordX(costrast,ncoordx,ncoordy); |
| | 625 | ncostrasty := ST_World2RasterCoordY(costrast,ncoordx,ncoordy); |
| | 626 | ncostrastval := ST_Value(costrast,band,ncostrastx,ncostrasty); |
| | 627 | nnewcostval := (costval + ncostrastval)/2; |
| | 628 | ncostval := ST_Value(newrast,band,nx,ny); |
| | 629 | IF ncostval <> newnodatavalue THEN |
| | 630 | IF nnewcostval < ncostval THEN |
| | 631 | ncostval := nnewcostval; |
| | 632 | arrayid := arrayid + 1; |
| | 633 | node.id := arrayid; |
| | 634 | node.x := nx; |
| | 635 | node.y := ny; |
| | 636 | node.val := ncostval; |
| | 637 | costarray := ARRAY_APPEND(costarray,node); |
| | 638 | newrast := ST_SetValue(newrast, band, nx, ny, ncostval); |
| | 639 | END IF; |
| | 640 | END IF; |
| | 641 | ELSE |
| | 642 | newrast := ST_SetValue(newrast, band, nx, ny, newnodatavalue); |
| | 643 | END IF; |
| | 644 | END IF; |
| | 645 | |
| | 646 | |
| | 647 | -- Calculate cost distance for neighbors in diagonal directions |
| | 648 | -- neighbor(x-1,y+1) |
| | 649 | nx := x-1; |
| | 650 | ny := y+1; |
| | 651 | IF nx >= 1 AND ny <= newheight THEN |
| | 652 | ncoordx := ST_Raster2WorldCoordX(newrast, x, y); |
| | 653 | ncoordy := ST_Raster2WorldCoordY(newrast, x, y); |
| | 654 | IF ST_Within(ST_SetSRID(ST_MakePoint(ncoordx,ncoordy),ST_SRID(costrast)),ST_Envelope(costrast)) THEN |
| | 655 | ncostrastx := ST_World2RasterCoordX(costrast,ncoordx,ncoordy); |
| | 656 | ncostrasty := ST_World2RasterCoordY(costrast,ncoordx,ncoordy); |
| | 657 | ncostrastval := ST_Value(costrast,band,ncostrastx,ncostrasty); |
| | 658 | nnewcostval := sqrt(2) * (costval + ncostrastval)/2; |
| | 659 | ncostval := ST_Value(newrast,band,nx,ny); |
| | 660 | IF ncostval <> newnodatavalue THEN |
| | 661 | IF nnewcostval < ncostval THEN |
| | 662 | ncostval := nnewcostval; |
| | 663 | arrayid := arrayid + 1; |
| | 664 | node.id := arrayid; |
| | 665 | node.x := nx; |
| | 666 | node.y := ny; |
| | 667 | node.val := ncostval; |
| | 668 | costarray := ARRAY_APPEND(costarray,node); |
| | 669 | newrast := ST_SetValue(newrast, band, nx, ny, ncostval); |
| | 670 | END IF; |
| | 671 | END IF; |
| | 672 | ELSE |
| | 673 | newrast := ST_SetValue(newrast, band, nx, ny, newnodatavalue); |
| | 674 | END IF; |
| | 675 | END IF; |
| | 676 | |
| | 677 | -- neighbor(x-1,y-1) |
| | 678 | nx := x-1; |
| | 679 | ny := y-1; |
| | 680 | IF nx >= 1 AND ny >= 1 THEN |
| | 681 | ncoordx := ST_Raster2WorldCoordX(newrast, x, y); |
| | 682 | ncoordy := ST_Raster2WorldCoordY(newrast, x, y); |
| | 683 | IF ST_Within(ST_SetSRID(ST_MakePoint(ncoordx,ncoordy),ST_SRID(costrast)),ST_Envelope(costrast)) THEN |
| | 684 | ncostrastx := ST_World2RasterCoordX(costrast,ncoordx,ncoordy); |
| | 685 | ncostrasty := ST_World2RasterCoordY(costrast,ncoordx,ncoordy); |
| | 686 | ncostrastval := ST_Value(costrast,band,ncostrastx,ncostrasty); |
| | 687 | nnewcostval := sqrt(2) * (costval + ncostrastval)/2; |
| | 688 | ncostval := ST_Value(newrast,band,nx,ny); |
| | 689 | IF ncostval <> newnodatavalue THEN |
| | 690 | IF nnewcostval < ncostval THEN |
| | 691 | ncostval := nnewcostval; |
| | 692 | arrayid := arrayid + 1; |
| | 693 | node.id := arrayid; |
| | 694 | node.x := nx; |
| | 695 | node.y := ny; |
| | 696 | node.val := ncostval; |
| | 697 | costarray := ARRAY_APPEND(costarray,node); |
| | 698 | newrast := ST_SetValue(newrast, band, nx, ny, ncostval); |
| | 699 | END IF; |
| | 700 | END IF; |
| | 701 | ELSE |
| | 702 | newrast := ST_SetValue(newrast, band, nx, ny, newnodatavalue); |
| | 703 | END IF; |
| | 704 | END IF; |
| | 705 | |
| | 706 | -- neighbor(x+1,y+1) |
| | 707 | nx := x+1; |
| | 708 | ny := y+1; |
| | 709 | IF nx <= newwidth AND ny <= newheight THEN |
| | 710 | ncoordx := ST_Raster2WorldCoordX(newrast, x, y); |
| | 711 | ncoordy := ST_Raster2WorldCoordY(newrast, x, y); |
| | 712 | IF ST_Within(ST_SetSRID(ST_MakePoint(ncoordx,ncoordy),ST_SRID(costrast)),ST_Envelope(costrast)) THEN |
| | 713 | ncostrastx := ST_World2RasterCoordX(costrast,ncoordx,ncoordy); |
| | 714 | ncostrasty := ST_World2RasterCoordY(costrast,ncoordx,ncoordy); |
| | 715 | ncostrastval := ST_Value(costrast,band,ncostrastx,ncostrasty); |
| | 716 | nnewcostval := sqrt(2) * (costval + ncostrastval)/2; |
| | 717 | ncostval := ST_Value(newrast,band,nx,ny); |
| | 718 | IF ncostval <> newnodatavalue THEN |
| | 719 | IF nnewcostval < ncostval THEN |
| | 720 | ncostval := nnewcostval; |
| | 721 | arrayid := arrayid + 1; |
| | 722 | node.id := arrayid; |
| | 723 | node.x := nx; |
| | 724 | node.y := ny; |
| | 725 | node.val := ncostval; |
| | 726 | costarray := ARRAY_APPEND(costarray,node); |
| | 727 | newrast := ST_SetValue(newrast, band, nx, ny, ncostval); |
| | 728 | END IF; |
| | 729 | END IF; |
| | 730 | ELSE |
| | 731 | newrast := ST_SetValue(newrast, band, nx, ny, newnodatavalue); |
| | 732 | END IF; |
| | 733 | END IF; |
| | 734 | |
| | 735 | -- neighbor(x+1,y-1) |
| | 736 | nx := x+1; |
| | 737 | ny := y-1; |
| | 738 | IF nx <= newwidth AND ny >= 1 THEN |
| | 739 | ncoordx := ST_Raster2WorldCoordX(newrast, x, y); |
| | 740 | ncoordy := ST_Raster2WorldCoordY(newrast, x, y); |
| | 741 | IF ST_Within(ST_SetSRID(ST_MakePoint(ncoordx,ncoordy),ST_SRID(costrast)),ST_Envelope(costrast)) THEN |
| | 742 | ncostrastx := ST_World2RasterCoordX(costrast,ncoordx,ncoordy); |
| | 743 | ncostrasty := ST_World2RasterCoordY(costrast,ncoordx,ncoordy); |
| | 744 | ncostrastval := ST_Value(costrast,band,ncostrastx,ncostrasty); |
| | 745 | nnewcostval := sqrt(2) * (costval + ncostrastval)/2; |
| | 746 | ncostval := ST_Value(newrast,band,nx,ny); |
| | 747 | IF ncostval <> newnodatavalue THEN |
| | 748 | IF nnewcostval < ncostval THEN |
| | 749 | ncostval := nnewcostval; |
| | 750 | arrayid := arrayid + 1; |
| | 751 | node.id := arrayid; |
| | 752 | node.x := nx; |
| | 753 | node.y := ny; |
| | 754 | node.val := ncostval; |
| | 755 | costarray := ARRAY_APPEND(costarray,node); |
| | 756 | newrast := ST_SetValue(newrast, band, nx, ny, ncostval); |
| | 757 | END IF; |
| | 758 | END IF; |
| | 759 | ELSE |
| | 760 | newrast := ST_SetValue(newrast, band, nx, ny, newnodatavalue); |
| | 761 | END IF; |
| | 762 | END IF; |
| | 763 | |
| | 764 | END IF; |
| | 765 | END LOOP; |
| | 766 | |
| | 767 | RETURN newrast; |
| | 768 | END; |
| | 769 | $$ |
| | 770 | LANGUAGE 'plpgsql'; |
| | 771 | |
| | 772 | |
| | 773 | -------------------------------------------------------------------- |
| | 774 | -- ST_CostDistance - Return a raster generated from a set of raster specifications |
| | 775 | -- raster a table and a one band cost raster, which values |
| | 776 | -- are the the least accumulative cost of traversing |
| | 777 | -- the cost surface from source points to each cell. |
| | 778 | -- (points for now, lines or polygons in the future). |
| | 779 | -- Arguments |
| | 780 | -- width,height,rastulx,rastuly,rastscalex,rastscaley,rastskewx,rastskewy |
| | 781 | -- - Dimenssions and georeference of resulted raster. |
| | 782 | -- rastsrid - SRID of the resulted raster |
| | 783 | -- rastndv - Nodata value for resulted raster |
| | 784 | -- pixeltype text - Pixeltype assigned to the resulting raster. By default |
| | 785 | -- to be the pixeltype of the reference raster if not specified. |
| | 786 | -- costrast raster - Cost raster in which each cell value represents the |
| | 787 | -- cost of traversing this cell. |
| | 788 | -- sourceschema text - Database schema of the source geometry table. |
| | 789 | -- sourcetable text - Source geometry table name. |
| | 790 | -- sourcegeomcolumn text - Source geometry table geometry column name. |
| | 791 | -- maxdist double precision - Maximum distance from pixel to the source |
| | 792 | -- when the source is too far from the pixel. |
| | 793 | -- Pixel that exceeds it will be assigned nodatavalue. |
| | 794 | -------------------------------------------------------------------- |
| | 795 | DROP FUNCTION IF EXISTS ST_CostDistance(width integer, |
| | 796 | height integer, |
| | 797 | rastulx float8, |
| | 798 | rastuly float8, |
| | 799 | rastscalex float8, |
| | 800 | rastscaley float8, |
| | 801 | rastskewx float8, |
| | 802 | rastskewy float8, |
| | 803 | rastsrid integer, |
| | 804 | rastndv float8, |
| | 805 | pixeltype text, |
| | 806 | costrast raster, |
| | 807 | sourceschema text, |
| | 808 | sourcetable text, |
| | 809 | sourcegeomcolumn text, |
| | 810 | double precision = -1); |
| | 811 | CREATE OR REPLACE FUNCTION ST_CostDistance(width integer, |
| | 812 | height integer, |
| | 813 | rastulx float8, |
| | 814 | rastuly float8, |
| | 815 | rastscalex float8, |
| | 816 | rastscaley float8, |
| | 817 | rastskewx float8, |
| | 818 | rastskewy float8, |
| | 819 | rastsrid integer, |
| | 820 | rastndv float8, |
| | 821 | pixeltype text, |
| | 822 | costrast raster, |
| | 823 | sourceschema text, |
| | 824 | sourcetable text, |
| | 825 | sourcegeomcolumn text, |
| | 826 | double precision = -1) |
| | 827 | RETURNS raster AS |
| | 828 | $$ |
| | 829 | DECLARE |
| | 830 | maxdist ALIAS FOR $7; |
| | 831 | newrast raster; |
| | 832 | newwidth integer; |
| | 833 | newheight integer; |
| | 834 | newsrid integer; |
| | 835 | newpixeltype text; |
| | 836 | newnodatavalue float8; |
| | 837 | newinitialvalue float8; |
| | 838 | |
| | 839 | x integer; |
| | 840 | y integer; |
| | 841 | sourcex float8; |
| | 842 | sourcey float8; |
| | 843 | sourcexr integer; |
| | 844 | sourceyr integer; |
| | 845 | sourcesrid integer; |
| | 846 | sourceboxgeom geometry; |
| | 847 | |
| | 848 | costarray p_node[] = '{}'; |
| | 849 | node p_node; |
| | 850 | costval float8; |
| | 851 | |
| | 852 | -- Assuming reference raster has only one band |
| | 853 | band integer := 1; |
| | 854 | |
| | 855 | nx integer; |
| | 856 | ny integer; |
| | 857 | ncoordx float8; |
| | 858 | ncoordy float8; |
| | 859 | ncostval float8; |
| | 860 | nnewcostval float8; |
| | 861 | ncostrastx integer; |
| | 862 | ncostrasty integer; |
| | 863 | ncostrastval float8; |
| | 864 | |
| | 865 | arrayid integer := 0; |
| | 866 | tempnode p_node[]; |
| | 867 | minval float8; |
| | 868 | minnodeid int; |
| | 869 | exesql text; |
| | 870 | geom geometry; |
| | 871 | flag boolean := False; |
| | 872 | BEGIN |
| | 873 | -- Check if cost raster is NULL |
| | 874 | IF costrast IS NULL THEN |
| | 875 | RAISE NOTICE 'ST_CostDistance: Cost raster is NULL. Returning NULL'; |
| | 876 | RETURN NULL; |
| | 877 | END IF; |
| | 878 | |
| | 879 | newwidth := width; |
| | 880 | newheight := height; |
| | 881 | newsrid := rastsrid; |
| | 882 | |
| | 883 | -- Assuming source point table has one SRID for all geometries |
| | 884 | EXECUTE 'SELECT DISTINCT ST_SRID(' || sourcegeomcolumn || ') FROM ' || sourceschema || '.' || sourcetable || ';' INTO sourcesrid; |
| | 885 | |
| | 886 | -- Create a new empty raster having the same georeference as the reference raster |
| | 887 | newrast := ST_MakeEmptyRaster(width, height, rastulx, rastuly, rastscalex,rastscaley, rastskewx, rastskewy, rastsrid); |
| | 888 | |
| | 889 | -- Check if the new raster is empty (width = 0 OR height = 0) |
| | 890 | IF ST_IsEmpty(newrast) THEN |
| | 891 | RAISE NOTICE 'ST_CostDistance: Raster is empty. Returning an empty raster'; |
| | 892 | RETURN newrast; |
| | 893 | END IF; |
| | 894 | |
| | 895 | -- Set the new pixeltype |
| | 896 | newpixeltype := pixeltype; |
| | 897 | -- If pixeltype not specified then use the pixeltype of the reference raster |
| | 898 | IF newpixeltype IS NULL THEN |
| | 899 | newpixeltype := ST_BandPixelType(refrast, band); |
| | 900 | ELSIF newpixeltype != '1BB' AND newpixeltype != '2BUI' AND newpixeltype != '4BUI' AND newpixeltype != '8BSI' AND newpixeltype != '8BUI' AND |
| | 901 | newpixeltype != '16BSI' AND newpixeltype != '16BUI' AND newpixeltype != '32BSI' AND newpixeltype != '32BUI' AND newpixeltype != '32BF' AND newpixeltype != '64BF' THEN |
| | 902 | RAISE EXCEPTION 'ST_CostDistance: Invalid pixeltype "%". Aborting.', newpixeltype; |
| | 903 | END IF; |
| | 904 | |
| | 905 | -- Check for notada value |
| | 906 | newnodatavalue := ST_BandNodataValue(refrast, band); |
| | 907 | IF newnodatavalue IS NULL OR newnodatavalue < ST_MinPossibleValue(newpixeltype) OR newnodatavalue > (-ST_MinPossibleValue(newpixeltype) - 1) THEN |
| | 908 | RAISE NOTICE 'ST_CostDistance: Reference raster do not have a nodata value or is out of range for the new raster pixeltype, nodata value for new raster set to the min value possible'; |
| | 909 | newnodatavalue := ST_MinPossibleValue(newpixeltype); |
| | 910 | END IF; |
| | 911 | -- We set the initial value of the resulting raster to nodata value. |
| | 912 | -- If nodatavalue is null then the raster will be initialise to ST_MinPossibleValue |
| | 913 | newinitialvalue := newnodatavalue; |
| | 914 | |
| | 915 | -- Create the raster receiving all the computed cost distance values. Initialize it to the new initial value. |
| | 916 | newrast := ST_AddBand(newrast, newpixeltype, newinitialvalue, newnodatavalue); |
| | 917 | |
| | 918 | -- Check if source points boundary intersects with extent of cost raster, if not, return new raster initiated with no data value. |
| | 919 | exesql := 'SELECT ST_CONVEXHULL(ST_COLLECT(' || sourcegeomcolumn || ')) FROM ' || sourceschema || '.' || sourcetable || ';'; |
| | 920 | EXECUTE exesql INTO sourceboxgeom; |
| | 921 | SELECT ST_Intersects(costrast,sourceboxgeom) INTO flag; |
| | 922 | IF NOT flag THEN |
| | 923 | RAISE NOTICE 'ST_CostDistance: Source points are out side of the cost raster. Returning raster with no data values.'; |
| | 924 | RETURN newrast; |
| | 925 | END IF; |
| | 926 | |
| | 927 | -- Set raster pixel value to nodatavalue or zero if pixel is source point; |
| | 928 | -- Initialize cost_array with source points that are within the extent of cost raster. |
| | 929 | exesql := 'SELECT ' || sourcegeomcolumn || ' FROM ' || sourceschema || '.' || sourcetable || ';'; |
| | 930 | FOR geom IN EXECUTE(exesql) LOOP |
| | 931 | sourcex := ST_X(geom); |
| | 932 | sourcey := ST_Y(geom); |
| | 933 | sourcexr := ST_World2RasterCoordX(newrast, sourcex, sourcey); |
| | 934 | sourceyr := ST_World2RasterCoordY(newrast, sourcex, sourcey); |
| | 935 | -- If source point within new raster extent |
| | 936 | IF sourcexr <= width AND sourceyr <= height THEN |
| | 937 | -- If source point within cost raster extent, set new raster pixel value to zero |
| | 938 | -- since there is no accumulative cost to return to itself; |
| | 939 | -- Add source point to cost array. |
| | 940 | IF ST_Within(ST_SetSRID(ST_MakePoint(sourcex,sourcey),ST_SRID(costrast)),ST_Envelope(costrast)) THEN |
| | 941 | newrast := ST_SetValue(newrast, band, sourcexr, sourceyr, 0); |
| | 942 | arrayid := arrayid + 1; |
| | 943 | node.id := arrayid; |
| | 944 | node.x := sourcexr; |
| | 945 | node.y := sourceyr; |
| | 946 | node.val := costval; |
| | 947 | costarray := ARRAY_APPEND(costarray,node); |
| | 948 | END IF; |
| | 949 | END IF; |
| | 950 | END LOOP; |
| | 951 | |
| | 952 | -- Loop through the cost array, pop up node with least accumulative cost value; |
| | 953 | -- Calculate cost values for its neighbors (8 directions); |
| | 954 | flag := True; |
| | 955 | WHILE flag LOOP |
| | 956 | -- End loop when cost values in the cost array are all NULL |
| | 957 | SELECT ARRAY_AGG(cv) FROM (SELECT DISTINCT explode_array(costarray) AS cv) AS foo INTO tempnode; |
| | 958 | IF ARRAY_LENGTH(tempnode,1) = 1 AND tempnode[1] = NULL THEN |
| | 959 | flag := False; |
| | 960 | ELSE |
| | 961 | SELECT MIN(costarray[i].val) FROM GENERATE_SERIES(1,ARRAY_UPPER(costarray,1)) AS i INTO minval; |
| | 962 | SELECT costarray[i].id FROM GENERATE_SERIES(1,ARRAY_UPPER(costarray,1)) AS i WHERE costarray[i].val = minval INTO minnodeid; |
| | 963 | -- Pop up node with min cost value, set its val in the array to be NULL |
| | 964 | x := costarray[minnodeid].x; |
| | 965 | y := costarray[minnodeid].y; |
| | 966 | costval := ST_Value(newrast,band,x,y); |
| | 967 | costarray[minnodeid] := NULL; |
| | 968 | -- Calculate cost distance for neighbors in perpendicular directions |
| | 969 | -- neighbor(x,y+1) |
| | 970 | nx := x; |
| | 971 | ny := y+1; |
| | 972 | IF ny <= newheight THEN |
| | 973 | ncoordx := ST_Raster2WorldCoordX(newrast, x, y); |
| | 974 | ncoordy := ST_Raster2WorldCoordY(newrast, x, y); |
| | 975 | IF ST_Within(ST_SetSRID(ST_MakePoint(ncoordx,ncoordy),ST_SRID(costrast)),ST_Envelope(costrast)) THEN |
| | 976 | ncostrastx := ST_World2RasterCoordX(costrast,ncoordx,ncoordy); |
| | 977 | ncostrasty := ST_World2RasterCoordY(costrast,ncoordx,ncoordy); |
| | 978 | ncostrastval := ST_Value(costrast,band,ncostrastx,ncostrasty); |
| | 979 | nnewcostval := (costval + ncostrastval)/2; |
| | 980 | ncostval := ST_Value(newrast,band,nx,ny); |
| | 981 | IF ncostval <> newnodatavalue THEN |
| | 982 | IF nnewcostval < ncostval THEN |
| | 983 | ncostval := nnewcostval; |
| | 984 | arrayid := arrayid + 1; |
| | 985 | node.id := arrayid; |
| | 986 | node.x := nx; |
| | 987 | node.y := ny; |
| | 988 | node.val := ncostval; |
| | 989 | costarray := ARRAY_APPEND(costarray,node); |
| | 990 | newrast := ST_SetValue(newrast, band, nx, ny, ncostval); |
| | 991 | END IF; |
| | 992 | END IF; |
| | 993 | ELSE |
| | 994 | newrast := ST_SetValue(newrast, band, nx, ny, newnodatavalue); |
| | 995 | END IF; |
| | 996 | END IF; |
| | 997 | |
| | 998 | -- neighbor(x,y-1) |
| | 999 | nx := x; |
| | 1000 | ny := y-1; |
| | 1001 | IF ny >= 1 THEN |
| | 1002 | ncoordx := ST_Raster2WorldCoordX(newrast, x, y); |
| | 1003 | ncoordy := ST_Raster2WorldCoordY(newrast, x, y); |
| | 1004 | IF ST_Within(ST_SetSRID(ST_MakePoint(ncoordx,ncoordy),ST_SRID(costrast)),ST_Envelope(costrast)) THEN |
| | 1005 | ncostrastx := ST_World2RasterCoordX(costrast,ncoordx,ncoordy); |
| | 1006 | ncostrasty := ST_World2RasterCoordY(costrast,ncoordx,ncoordy); |
| | 1007 | ncostrastval := ST_Value(costrast,band,ncostrastx,ncostrasty); |
| | 1008 | nnewcostval := (costval + ncostrastval)/2; |
| | 1009 | ncostval := ST_Value(newrast,band,nx,ny); |
| | 1010 | IF ncostval <> newnodatavalue THEN |
| | 1011 | IF nnewcostval < ncostval THEN |
| | 1012 | -- If max distance specified |
| | 1013 | IF maxdist != -1 THEN |
| | 1014 | -- Any distance exceeds max distance is assigned nodata value |
| | 1015 | IF nnewcostval > maxdist THEN |
| | 1016 | nnewcostval := newnodatavalue; |
| | 1017 | newrast := ST_SetValue(newrast, band, nx, ny, newnodatavalue); |
| | 1018 | END IF; |
| | 1019 | END IF; |
| | 1020 | if nnewcostval <> newnodatavalue THEN |
| | 1021 | ncostval := nnewcostval; |
| | 1022 | arrayid := arrayid + 1; |
| | 1023 | node.id := arrayid; |
| | 1024 | node.x := nx; |
| | 1025 | node.y := ny; |
| | 1026 | node.val := ncostval; |
| | 1027 | costarray := ARRAY_APPEND(costarray,node); |
| | 1028 | newrast := ST_SetValue(newrast, band, nx, ny, ncostval); |
| | 1029 | END IF; |
| | 1030 | END IF; |
| | 1031 | END IF; |
| | 1032 | ELSE |
| | 1033 | newrast := ST_SetValue(newrast, band, nx, ny, newnodatavalue); |
| | 1034 | END IF; |
| | 1035 | END IF; |
| | 1036 | |
| | 1037 | -- neighbor(x+1,y) |
| | 1038 | nx := x+1; |
| | 1039 | ny := y; |
| | 1040 | IF nx <= newwidth THEN |
| | 1041 | ncoordx := ST_Raster2WorldCoordX(newrast, x, y); |
| | 1042 | ncoordy := ST_Raster2WorldCoordY(newrast, x, y); |
| | 1043 | IF ST_Within(ST_SetSRID(ST_MakePoint(ncoordx,ncoordy),ST_SRID(costrast)),ST_Envelope(costrast)) THEN |
| | 1044 | ncostrastx := ST_World2RasterCoordX(costrast,ncoordx,ncoordy); |
| | 1045 | ncostrasty := ST_World2RasterCoordY(costrast,ncoordx,ncoordy); |
| | 1046 | ncostrastval := ST_Value(costrast,band,ncostrastx,ncostrasty); |
| | 1047 | nnewcostval := (costval + ncostrastval)/2; |
| | 1048 | ncostval := ST_Value(newrast,band,nx,ny); |
| | 1049 | IF ncostval <> newnodatavalue THEN |
| | 1050 | IF nnewcostval < ncostval THEN |
| | 1051 | ncostval := nnewcostval; |
| | 1052 | arrayid := arrayid + 1; |
| | 1053 | node.id := arrayid; |
| | 1054 | node.x := nx; |
| | 1055 | node.y := ny; |
| | 1056 | node.val := ncostval; |
| | 1057 | costarray := ARRAY_APPEND(costarray,node); |
| | 1058 | newrast := ST_SetValue(newrast, band, nx, ny, ncostval); |
| | 1059 | END IF; |
| | 1060 | END IF; |
| | 1061 | ELSE |
| | 1062 | newrast := ST_SetValue(newrast, band, nx, ny, newnodatavalue); |
| | 1063 | END IF; |
| | 1064 | END IF; |
| | 1065 | |
| | 1066 | -- neighbor(x-1,y) |
| | 1067 | nx := x-1; |
| | 1068 | ny := y; |
| | 1069 | IF nx >= 1 THEN |
| | 1070 | ncoordx := ST_Raster2WorldCoordX(newrast, x, y); |
| | 1071 | ncoordy := ST_Raster2WorldCoordY(newrast, x, y); |
| | 1072 | IF ST_Within(ST_SetSRID(ST_MakePoint(ncoordx,ncoordy),ST_SRID(costrast)),ST_Envelope(costrast)) THEN |
| | 1073 | ncostrastx := ST_World2RasterCoordX(costrast,ncoordx,ncoordy); |
| | 1074 | ncostrasty := ST_World2RasterCoordY(costrast,ncoordx,ncoordy); |
| | 1075 | ncostrastval := ST_Value(costrast,band,ncostrastx,ncostrasty); |
| | 1076 | nnewcostval := (costval + ncostrastval)/2; |
| | 1077 | ncostval := ST_Value(newrast,band,nx,ny); |
| | 1078 | IF ncostval <> newnodatavalue THEN |
| | 1079 | IF nnewcostval < ncostval THEN |
| | 1080 | ncostval := nnewcostval; |
| | 1081 | arrayid := arrayid + 1; |
| | 1082 | node.id := arrayid; |
| | 1083 | node.x := nx; |
| | 1084 | node.y := ny; |
| | 1085 | node.val := ncostval; |
| | 1086 | costarray := ARRAY_APPEND(costarray,node); |
| | 1087 | newrast := ST_SetValue(newrast, band, nx, ny, ncostval); |
| | 1088 | END IF; |
| | 1089 | END IF; |
| | 1090 | ELSE |
| | 1091 | newrast := ST_SetValue(newrast, band, nx, ny, newnodatavalue); |
| | 1092 | END IF; |
| | 1093 | END IF; |
| | 1094 | |
| | 1095 | |
| | 1096 | -- Calculate cost distance for neighbors in diagonal directions |
| | 1097 | -- neighbor(x-1,y+1) |
| | 1098 | nx := x-1; |
| | 1099 | ny := y+1; |
| | 1100 | IF nx >= 1 AND ny <= newheight THEN |
| | 1101 | ncoordx := ST_Raster2WorldCoordX(newrast, x, y); |
| | 1102 | ncoordy := ST_Raster2WorldCoordY(newrast, x, y); |
| | 1103 | IF ST_Within(ST_SetSRID(ST_MakePoint(ncoordx,ncoordy),ST_SRID(costrast)),ST_Envelope(costrast)) THEN |
| | 1104 | ncostrastx := ST_World2RasterCoordX(costrast,ncoordx,ncoordy); |
| | 1105 | ncostrasty := ST_World2RasterCoordY(costrast,ncoordx,ncoordy); |
| | 1106 | ncostrastval := ST_Value(costrast,band,ncostrastx,ncostrasty); |
| | 1107 | nnewcostval := sqrt(2) * (costval + ncostrastval)/2; |
| | 1108 | ncostval := ST_Value(newrast,band,nx,ny); |
| | 1109 | IF ncostval <> newnodatavalue THEN |
| | 1110 | IF nnewcostval < ncostval THEN |
| | 1111 | ncostval := nnewcostval; |
| | 1112 | arrayid := arrayid + 1; |
| | 1113 | node.id := arrayid; |
| | 1114 | node.x := nx; |
| | 1115 | node.y := ny; |
| | 1116 | node.val := ncostval; |
| | 1117 | costarray := ARRAY_APPEND(costarray,node); |
| | 1118 | newrast := ST_SetValue(newrast, band, nx, ny, ncostval); |
| | 1119 | END IF; |
| | 1120 | END IF; |
| | 1121 | ELSE |
| | 1122 | newrast := ST_SetValue(newrast, band, nx, ny, newnodatavalue); |
| | 1123 | END IF; |
| | 1124 | END IF; |
| | 1125 | |
| | 1126 | -- neighbor(x-1,y-1) |
| | 1127 | nx := x-1; |
| | 1128 | ny := y-1; |
| | 1129 | IF nx >= 1 AND ny >= 1 THEN |
| | 1130 | ncoordx := ST_Raster2WorldCoordX(newrast, x, y); |
| | 1131 | ncoordy := ST_Raster2WorldCoordY(newrast, x, y); |
| | 1132 | IF ST_Within(ST_SetSRID(ST_MakePoint(ncoordx,ncoordy),ST_SRID(costrast)),ST_Envelope(costrast)) THEN |
| | 1133 | ncostrastx := ST_World2RasterCoordX(costrast,ncoordx,ncoordy); |
| | 1134 | ncostrasty := ST_World2RasterCoordY(costrast,ncoordx,ncoordy); |
| | 1135 | ncostrastval := ST_Value(costrast,band,ncostrastx,ncostrasty); |
| | 1136 | nnewcostval := sqrt(2) * (costval + ncostrastval)/2; |
| | 1137 | ncostval := ST_Value(newrast,band,nx,ny); |
| | 1138 | IF ncostval <> newnodatavalue THEN |
| | 1139 | IF nnewcostval < ncostval THEN |
| | 1140 | ncostval := nnewcostval; |
| | 1141 | arrayid := arrayid + 1; |
| | 1142 | node.id := arrayid; |
| | 1143 | node.x := nx; |
| | 1144 | node.y := ny; |
| | 1145 | node.val := ncostval; |
| | 1146 | costarray := ARRAY_APPEND(costarray,node); |
| | 1147 | newrast := ST_SetValue(newrast, band, nx, ny, ncostval); |
| | 1148 | END IF; |
| | 1149 | END IF; |
| | 1150 | ELSE |
| | 1151 | newrast := ST_SetValue(newrast, band, nx, ny, newnodatavalue); |
| | 1152 | END IF; |
| | 1153 | END IF; |
| | 1154 | |
| | 1155 | -- neighbor(x+1,y+1) |
| | 1156 | nx := x+1; |
| | 1157 | ny := y+1; |
| | 1158 | IF nx <= newwidth AND ny <= newheight THEN |
| | 1159 | ncoordx := ST_Raster2WorldCoordX(newrast, x, y); |
| | 1160 | ncoordy := ST_Raster2WorldCoordY(newrast, x, y); |
| | 1161 | IF ST_Within(ST_SetSRID(ST_MakePoint(ncoordx,ncoordy),ST_SRID(costrast)),ST_Envelope(costrast)) THEN |
| | 1162 | ncostrastx := ST_World2RasterCoordX(costrast,ncoordx,ncoordy); |
| | 1163 | ncostrasty := ST_World2RasterCoordY(costrast,ncoordx,ncoordy); |
| | 1164 | ncostrastval := ST_Value(costrast,band,ncostrastx,ncostrasty); |
| | 1165 | nnewcostval := sqrt(2) * (costval + ncostrastval)/2; |
| | 1166 | ncostval := ST_Value(newrast,band,nx,ny); |
| | 1167 | IF ncostval <> newnodatavalue THEN |
| | 1168 | IF nnewcostval < ncostval THEN |
| | 1169 | ncostval := nnewcostval; |
| | 1170 | arrayid := arrayid + 1; |
| | 1171 | node.id := arrayid; |
| | 1172 | node.x := nx; |
| | 1173 | node.y := ny; |
| | 1174 | node.val := ncostval; |
| | 1175 | costarray := ARRAY_APPEND(costarray,node); |
| | 1176 | newrast := ST_SetValue(newrast, band, nx, ny, ncostval); |
| | 1177 | END IF; |
| | 1178 | END IF; |
| | 1179 | ELSE |
| | 1180 | newrast := ST_SetValue(newrast, band, nx, ny, newnodatavalue); |
| | 1181 | END IF; |
| | 1182 | END IF; |
| | 1183 | |
| | 1184 | -- neighbor(x+1,y-1) |
| | 1185 | nx := x+1; |
| | 1186 | ny := y-1; |
| | 1187 | IF nx <= newwidth AND ny >= 1 THEN |
| | 1188 | ncoordx := ST_Raster2WorldCoordX(newrast, x, y); |
| | 1189 | ncoordy := ST_Raster2WorldCoordY(newrast, x, y); |
| | 1190 | IF ST_Within(ST_SetSRID(ST_MakePoint(ncoordx,ncoordy),ST_SRID(costrast)),ST_Envelope(costrast)) THEN |
| | 1191 | ncostrastx := ST_World2RasterCoordX(costrast,ncoordx,ncoordy); |
| | 1192 | ncostrasty := ST_World2RasterCoordY(costrast,ncoordx,ncoordy); |
| | 1193 | ncostrastval := ST_Value(costrast,band,ncostrastx,ncostrasty); |
| | 1194 | nnewcostval := sqrt(2) * (costval + ncostrastval)/2; |
| | 1195 | ncostval := ST_Value(newrast,band,nx,ny); |
| | 1196 | IF ncostval <> newnodatavalue THEN |
| | 1197 | IF nnewcostval < ncostval THEN |
| | 1198 | ncostval := nnewcostval; |
| | 1199 | arrayid := arrayid + 1; |
| | 1200 | node.id := arrayid; |
| | 1201 | node.x := nx; |
| | 1202 | node.y := ny; |
| | 1203 | node.val := ncostval; |
| | 1204 | costarray := ARRAY_APPEND(costarray,node); |
| | 1205 | newrast := ST_SetValue(newrast, band, nx, ny, ncostval); |
| | 1206 | END IF; |
| | 1207 | END IF; |
| | 1208 | ELSE |
| | 1209 | newrast := ST_SetValue(newrast, band, nx, ny, newnodatavalue); |
| | 1210 | END IF; |
| | 1211 | END IF; |
| | 1212 | |
| | 1213 | END IF; |
| | 1214 | END LOOP; |
| | 1215 | |
| | 1216 | RETURN newrast; |
| | 1217 | END; |
| | 1218 | $$ |
| | 1219 | LANGUAGE 'plpgsql'; |
| | 1220 | }}} |
