Changes between Version 76 and Version 77 of WKTRaster/SpecificationWorking03

Timestamp:

05/16/11 11:05:03 (14 years ago)

Author:

dustymugs

Comment:

ST_Mean

WKTRaster/SpecificationWorking03

@@ -285 +285 @@
 
 The mean returned in the coverage functions (has rastertable and rastercolumn arguments) is a weighted mean of the means of each raster tile. The standard deviation returned is the cumulative standard deviation of all raster tiles.
+
+----
+
+'''ST_Mean(raster, nband) -> double precision'''[[BR]]
+This function calls ST_SummaryStats and only returns the mean from that function.
+
+1. ST_Mean(rast raster, nband int, hasnodata boolean) -> double precision
+
+  returns the mean as a double precision
+
+  nband: index of band
+
+  hasnodata: if FALSE, any pixel who's value is nodata is ignored
+
+{{{
+ST_Mean(rast, 1, FALSE)
+}}}
+
+2. ST_Mean(rast raster, nband int) -> double precision
+
+  assumes hasnodata = FALSE
+
+{{{
+ST_Mean(rast, 2)
+}}}
+
+3. ST_Mean(rast raster, hasnodata boolean) -> double precision
+
+  assumes nband = 1
+
+{{{
+ST_Mean(rast, TRUE)
+}}}
+
+4. ST_Mean(rast raster) -> double precision
+
+  assumes nband = 1 and hasnodata = FALSE
+
+{{{
+ST_Mean(rast)
+}}}
+
+The set of ST_ApproxMean functions are:
+
+1. ST_ApproxMean(rast raster, nband int, hasnodata boolean, sample_percent double precision) -> double precision
+
+  sample_percent: a value between 0 and 1 indicating the percentage of the raster band's pixels to consider
+
+{{{
+ST_ApproxMean(rast, 3, FALSE, 0.1)
+
+ST_ApproxMean(rast, 1, TRUE, 0.5)
+}}}
+
+2. ST_ApproxMean(rast raster, nband int, sample_percent double precision) -> double precision
+
+  assumes that nband = 1
+
+{{{
+ST_ApproxMean(rast, 2 0.01)
+
+ST_ApproxMean(rast, 4, 0.025)
+}}}
+
+3. ST_ApproxMean(rast raster, hasnodata boolean, sample_percent double precision) -> double precision
+
+  assumes that nband = 1
+
+{{{
+ST_ApproxMean(rast, FALSE, 0.01)
+
+ST_ApproxMean(rast, TRUE, 0.025)
+}}}
+
+4. ST_ApproxMean(rast raster, sample_percent double precision) -> double precision
+
+  assumes that nband = 1 and hasnodata = FALSE
+
+{{{
+ST_ApproxMean(rast, 0.25)
+}}}
+
+5. ST_ApproxMean(rast raster) -> double precision
+
+  assumes that nband = 1, hasnodata = FALSE and sample_percent = 0.1
+
+{{{
+ST_ApproxMean(rast)
+}}}
+
+The following functions are provided for coverage tables.
+
+1. ST_Mean(rastertable text, rastercolumn text, nband int, hasnodata boolean) -> double precision
+
+  rastertable: name of table with raster column
+
+  rastercolumn: name of column of data type raster
+
+{{{
+ST_Mean('tmax_2010', 'rast', 1, FALSE)
+
+ST_Mean('precip_2011', 'rast', 1, TRUE)
+}}}
+
+2. ST_Mean(rastertable text, rastercolumn text, nband int) -> double precision
+
+    hasnodata = FALSE
+
+{{{
+ST_Mean('tmax_2010', 'rast', 1)
+}}}
+
+3. ST_Mean(rastertable text, rastercolumn text, hasnodata boolean) -> double precision
+
+    nband = 1
+
+{{{
+ST_Mean('precip_2011', 'rast', TRUE)
+}}}
+
+4. ST_Mean(rastertable text, rastercolumn text) -> double precision
+
+    nband = 1 and hasnodata = FALSE
+
+{{{
+ST_Mean('tmin_2009', 'rast')
+}}}
+
+Variations for ST_ApproxMean are:
+
+1. ST_ApproxMean(rastertable text, rastercolumn text, nband int, hasnodata boolean, sample_percent double precision) -> double precision
+
+{{{
+ST_ApproxMean('tmax_2010', 'rast', 1, FALSE, 0.5)
+
+ST_ApproxMean('precip_2011', 'rast', 1, TRUE, 0.2)
+}}}
+
+2. ST_ApproxMean(rastertable text, rastercolumn text, nband int, sample_percent double precision) -> double precision
+
+    hasnodata = FALSE
+
+{{{
+ST_ApproxMean('tmax_2010', 'rast', 1, 0.5)
+
+ST_ApproxMean('precip_2011', 'rast', 1, 0.2)
+}}}
+
+3. ST_ApproxMean(rastertable text, rastercolumn text, hasnodata boolean, sample_percent double precision) -> double precision
+
+    nband = 1
+
+{{{
+ST_ApproxMean('tmax_2010', 'rast', FALSE, 0.5)
+
+ST_ApproxMean('precip_2011', 'rast', TRUE, 0.2)
+}}}
+
+4. ST_ApproxMean(rastertable text, rastercolumn text, sample_percent double precision) -> double precision
+
+    nband = 1 and hasnodata = FALSE
+
+{{{
+ST_ApproxMean('tmax_2010', 'rast', 0.5)
+
+ST_ApproxMean('precip_2011', 'rast', 0.2)
+}}}
+
+5. ST_ApproxMean(rastertable text, rastercolumn text) -> double precision
+
+    nband = 1, hasnodata = FALSE and sample_percent = 0.1
+
+{{{
+ST_ApproxMean('tmax_2010', 'rast')
+
+ST_ApproxMean('precip_2011', 'rast')
+}}}
+
+The mean returned in the coverage functions (has rastertable and rastercolumn arguments) is a weighted mean of the means of each raster tile.
 
 ----