Changes between Version 81 and Version 82 of WKTRaster/SpecificationWorking03

Timestamp:

05/16/11 12:04:10 (14 years ago)

Author:

dustymugs

Comment:

ST_Quantile

WKTRaster/SpecificationWorking03

@@ -1881 +1881 @@
 
 ----
+'''ST_Quantile(raster, nband) -> set of records'''[[BR]]
+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.
+
+http://en.wikipedia.org/wiki/Quantile
+
+ST_Quantile variations:
+
+1. ST_Quantile(rast raster, nband int, hasnodata boolean, quantiles double precision[]) -> set of records
+
+  each row returned is of (quantile double precision, value double precision)
+
+  nband: index of band to process on
+
+  hasnodata: if FALSE, any pixel who's value is nodata is ignored.
+
+  quantiles: array of percentages to compute values for
+
+{{{
+ST_Quantile(rast, 1, FALSE, ARRAY[0.1, 0.3, 0.7])
+
+ST_Quantile(rast, 1, TRUE, ARRAY[0.2])
+
+ST_Quantile(rast, 1, FALSE, ARRAY[0, 1])
+}}}
+
+2. ST_Quantile(rast raster, nband int, quantiles double precision[]) -> set of records
+
+  "hasnodata" is assumed to be FALSE
+
+{{{
+ST_Quantile(rast, 1, ARRAY[0.1, 0.3, 0.7])
+}}}
+
+3. ST_Quantile(rast raster, nband int, hasnodata boolean) -> set of records
+
+  "quantiles" assumed to be ARRAY[0, 0.25, 0.5, 0.75, 1]
+
+4. ST_Quantile(rast raster, nband int) -> set of records
+
+  "hasnodata" is assumed to be FALSE and "quantiles" assumed to be ARRAY[0, 0.25, 0.5, 0.75, 1]
+
+5. ST_Quantile(rast raster, quantiles double precision[]) -> set of records
+
+  "nband" is assumed to be 1 and "hasnodata" is FALSE
+
+6. ST_Quantile(rast raster) -> set of records
+
+  "nband" is assumed to be 1 and "quantiles" assumed to be ARRAY[0, 0.25, 0.5, 0.75, 1]
+
+7. ST_Quantile(rast raster, nband int, hasnodata boolean, quantile double precision) -> record
+
+  quantile: the single percentile to compute
+
+8. ST_Quantile(rast raster, nband int, quantile double precision) -> record
+
+  "hasnodata" is assumed to be FALSE
+
+9. ST_Quantile(rast raster, hasnodata boolean, quantile double precision) -> record
+
+  "nband" is assumed to be 1
+
+10. ST_Quantile(rast raster, quantile double precision) -> record
+
+  "nband" is assumed to be 1  and "hasnodata" is assumed to be FALSE
+
+ST_ApproxQuantile adds a "sample_percent" indicating the percentage of the raster to sample
+
+1. ST_ApproxQuantile(rast raster, nband int, hasnodata boolean, sample_percent double precision, quantiles double precision[]) -> set of records
+
+  nband: index of band to process on
+
+  hasnodata: if FALSE, any pixel who's value is nodata is ignored
+
+  sample_percent: a value between 0 and 1 indicating the percentage of the raster band's pixels to consider when computing the quantiles
+
+  quantiles: array of percentages to compute values for
+
+{{{
+ST_ApproxQuantile(rast, 1, FALSE, 0.1, ARRAY[0.1, 0.3, 0.7])
+
+ST_ApproxQuantile(rast, 1, TRUE, .2, ARRAY[0.2])
+
+ST_ApproxQuantile(rast, 1, FALSE, 0.3, ARRAY[0, 1])
+}}}
+
+2. ST_ApproxQuantile(rast raster, nband int, sample_percent double precision, quantiles double precision[]) -> set of records
+
+  "hasnodata" is assumed to be FALSE
+
+{{{
+ST_ApproxQuantile(rast, 1, .05, ARRAY[0.1, 0.3, 0.7])
+}}}
+
+3. ST_ApproxQuantile(rast raster, nband int, sample_percent double precision) -> set of records
+
+  "hasnodata" is assumed to be FALSE and "quantiles" assumed to be ARRAY[0, 0.25, 0.5, 0.75, 1]
+
+4. ST_ApproxQuantile(rast raster, sample_percent double precision, quantiles double precision[]) -> set of records
+
+  "nband" is assumed to be 1
+
+5. ST_ApproxQuantile(rast raster, nband int, sample_percent double precision, quantile double precision) -> record
+
+  quantile: the single percentile to compute
+
+6. ST_ApproxQuantile(rast raster, sample_percent double precision, quantile double precision) -> record
+
+  "nband" is assumed to be 2
+
+7. ST_ApproxQuantile(rast raster, sample_percent double precision) -> set of records
+
+  "nband" is assumed to be 1 and "quantiles" assumed to be ARRAY[0, 0.25, 0.5, 0.75, 1]
+
+8. ST_ApproxQuantile(rast raster, nband int, quantile double precision) -> record
+
+  "sample_percent" assumed to be 0.1
+
+9. ST_ApproxQuantile(rast raster, quantiles double precision[]) -> set of records
+
+  "nband" is assumed to be 1 and "sample_percent" assumed to be 0.1
+
+10. ST_ApproxQuantile(rast raster, quantile double precision) -> record
+
+  "nband" assumed to be 1 and "sample_percent" assumed to be 0.1
+
+11. ST_ApproxQuantile(rast raster, nband int) -> set of records
+
+  "quantiles" assumed to be ARRAY[0, 0.25, 0.5, 0.75, 1] and "sample_percent" assumed to be 0.1
+
+12. ST_ApproxQuantile(rast raster) -> set of records
+
+  "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
+
+----
 == '''Objective FV.17 - Being able to refer to band by textual name.''' ==