RS_SummaryStats¶
Returns one summary statistic of a band’s pixel values as a double.
Usage¶
double RS_SummaryStats(rast: raster, stat_type: string)
double RS_SummaryStats(rast: raster, stat_type: string, band: integer)
double RS_SummaryStats(rast: raster, stat_type: string, band: integer, exclude_nodata: boolean)
Arguments¶
- rast (raster): Input raster
- stat_type (string): One of
count,sum,mean,stddev,minormax(case-insensitive).stddevis the population standard deviation. - band (integer): Band index (1-based). Defaults to 1 if not specified.
- exclude_nodata (boolean): Whether to leave pixels holding the band’s nodata value out of the statistic. Defaults to true.
Description¶
Over no pixels (for example, a band that is entirely nodata), count
and sum are 0 and the other statistics are NaN; over one pixel,
stddev is 0. A NaN pixel is left out as nodata when the band’s nodata
value is NaN. Otherwise it is data: it makes sum and mean NaN, and
stddev too unless it is the only pixel, while min and max skip it
unless every pixel is NaN.
An unknown stat_type, a band the raster does not have, or a 64-bit
integer pixel beyond 2^53 in magnitude (which a double cannot hold
exactly) is an error. Only 2-D rasters are supported.
Examples¶
SELECT RS_SummaryStats(RS_Example(), 'mean');
┌────────────────────────────────────────────┐
│ rs_summarystats(rs_example(),Utf8("mean")) │
│ float64 │
╞════════════════════════════════════════════╡
│ 1.0 │
└────────────────────────────────────────────┘
SELECT RS_SummaryStats(RS_Example(), 'count', 1, false);
┌─────────────────────────────────────────────────────────────────────┐
│ rs_summarystats(rs_example(),Utf8("count"),Int64(1),Boolean(false)) │
│ float64 │
╞═════════════════════════════════════════════════════════════════════╡
│ 2048.0 │
└─────────────────────────────────────────────────────────────────────┘