Changes between Version 77 and Version 78 of WKTRaster/SpecificationWorking03

Timestamp:

May 16, 2011, 11:19:02 AM (13 years ago)

Author:

Bborie Park

Comment:

ST_StdDev

WKTRaster/SpecificationWorking03

@@ -464 +464 @@
 
 The mean returned in the coverage functions (has rastertable and rastercolumn arguments) is a weighted mean of the means of each raster tile.
+
+----
+
+'''ST_StdDev(raster, nband) -> double precision'''[[BR]]
+This function calls ST_SummaryStats and only returns the standard deviation from that function.
+
+1. ST_StdDev(rast raster, nband int, hasnodata boolean) -> double precision
+
+  returns the standard deviation as a double precision
+
+  nband: index of band
+
+  hasnodata: if FALSE, any pixel who's value is nodata is ignored
+
+{{{
+ST_StdDev(rast, 1, FALSE)
+}}}
+
+2. ST_StdDev(rast raster, nband int) -> double precision
+
+  assumes hasnodata = FALSE
+
+{{{
+ST_StdDev(rast, 2)
+}}}
+
+3. ST_StdDev(rast raster, hasnodata boolean) -> double precision
+
+  assumes nband = 1
+
+{{{
+ST_StdDev(rast, TRUE)
+}}}
+
+4. ST_StdDev(rast raster) -> double precision
+
+  assumes nband = 1 and hasnodata = FALSE
+
+{{{
+ST_StdDev(rast)
+}}}
+
+The set of ST_ApproxStdDev functions are:
+
+1. ST_ApproxStdDev(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_ApproxStdDev(rast, 3, FALSE, 0.1)
+
+ST_ApproxStdDev(rast, 1, TRUE, 0.5)
+}}}
+
+2. ST_ApproxStdDev(rast raster, nband int, sample_percent double precision) -> double precision
+
+  assumes that nband = 1
+
+{{{
+ST_ApproxStdDev(rast, 2 0.01)
+
+ST_ApproxStdDev(rast, 4, 0.025)
+}}}
+
+3. ST_ApproxStdDev(rast raster, hasnodata boolean, sample_percent double precision) -> double precision
+
+  assumes that nband = 1
+
+{{{
+ST_ApproxStdDev(rast, FALSE, 0.01)
+
+ST_ApproxStdDev(rast, TRUE, 0.025)
+}}}
+
+4. ST_ApproxStdDev(rast raster, sample_percent double precision) -> double precision
+
+  assumes that nband = 1 and hasnodata = FALSE
+
+{{{
+ST_ApproxStdDev(rast, 0.25)
+}}}
+
+5. ST_ApproxStdDev(rast raster) -> double precision
+
+  assumes that nband = 1, hasnodata = FALSE and sample_percent = 0.1
+
+{{{
+ST_ApproxStdDev(rast)
+}}}
+
+The following functions are provided for coverage tables.
+
+1. ST_StdDev(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_StdDev('tmax_2010', 'rast', 1, FALSE)
+
+ST_StdDev('precip_2011', 'rast', 1, TRUE)
+}}}
+
+2. ST_StdDev(rastertable text, rastercolumn text, nband int) -> double precision
+
+    hasnodata = FALSE
+
+{{{
+ST_StdDev('tmax_2010', 'rast', 1)
+}}}
+
+3. ST_StdDev(rastertable text, rastercolumn text, hasnodata boolean) -> double precision
+
+    nband = 1
+
+{{{
+ST_StdDev('precip_2011', 'rast', TRUE)
+}}}
+
+4. ST_StdDev(rastertable text, rastercolumn text) -> double precision
+
+    nband = 1 and hasnodata = FALSE
+
+{{{
+ST_StdDev('tmin_2009', 'rast')
+}}}
+
+Variations for ST_ApproxStdDev are:
+
+1. ST_ApproxStdDev(rastertable text, rastercolumn text, nband int, hasnodata boolean, sample_percent double precision) -> double precision
+
+{{{
+ST_ApproxStdDev('tmax_2010', 'rast', 1, FALSE, 0.5)
+
+ST_ApproxStdDev('precip_2011', 'rast', 1, TRUE, 0.2)
+}}}
+
+2. ST_ApproxStdDev(rastertable text, rastercolumn text, nband int, sample_percent double precision) -> double precision
+
+    hasnodata = FALSE
+
+{{{
+ST_ApproxStdDev('tmax_2010', 'rast', 1, 0.5)
+
+ST_ApproxStdDev('precip_2011', 'rast', 1, 0.2)
+}}}
+
+3. ST_ApproxStdDev(rastertable text, rastercolumn text, hasnodata boolean, sample_percent double precision) -> double precision
+
+    nband = 1
+
+{{{
+ST_ApproxStdDev('tmax_2010', 'rast', FALSE, 0.5)
+
+ST_ApproxStdDev('precip_2011', 'rast', TRUE, 0.2)
+}}}
+
+4. ST_ApproxStdDev(rastertable text, rastercolumn text, sample_percent double precision) -> double precision
+
+    nband = 1 and hasnodata = FALSE
+
+{{{
+ST_ApproxStdDev('tmax_2010', 'rast', 0.5)
+
+ST_ApproxStdDev('precip_2011', 'rast', 0.2)
+}}}
+
+5. ST_ApproxStdDev(rastertable text, rastercolumn text) -> double precision
+
+    nband = 1, hasnodata = FALSE and sample_percent = 0.1
+
+{{{
+ST_ApproxStdDev('tmax_2010', 'rast')
+
+ST_ApproxStdDev('precip_2011', 'rast')
+}}}
+
+The standard deviation returned in the coverage functions (has rastertable and rastercolumn arguments) is the cumulative standard deviation of all raster tiles.
 
 ----