Changes between Version 74 and Version 75 of WKTRaster/SpecificationWorking03
- Timestamp:
- 05/11/11 16:26:12 (14 years ago)
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WKTRaster/SpecificationWorking03
v74 v75 105 105 As part of the process to provide complete implementations of ST_AsJPEG and ST_AsPNG, a method is required to reclassify larger numbers unable to be contained in 8BUI (JPEG and PNG) and 16BUI (PNG). For this reclassification function, we need to get the min and max values of a band, thus ST_MinMax. 106 106 107 1. ST_MinMax(rast raster, nband int, ignore_nodata boolean) -> record107 1. ST_MinMax(rast raster, nband int, hasnodata boolean) -> record 108 108 109 109 returns one record of two columns (min, max) … … 111 111 nband: index of band to process on 112 112 113 ignore_nodata: if TRUE, any pixel who's value is nodata is ignored.113 hasnodata: if FALSE, any pixel who's value is nodata is ignored. 114 114 115 115 {{{ … … 119 119 2. ST_MinMax(rast raster, nband int) -> record 120 120 121 assumes ignore_nodata = TRUE121 assumes hasnodata = FALSE 122 122 123 123 {{{ … … 125 125 }}} 126 126 127 3. ST_MinMax(rast raster, ignore_nodata boolean) -> record127 3. ST_MinMax(rast raster, hasnodata boolean) -> record 128 128 129 129 assumes band index = 1 … … 135 135 4. ST_MinMax(rast raster) -> record 136 136 137 assumes band index = 1 and ignore_nodata = TRUE137 assumes band index = 1 and hasnodata = FALSE 138 138 139 139 {{{ … … 149 149 The functions are: 150 150 151 1. ST_ApproxMinMax(rast raster, nband int, ignore_nodata boolean, sample_percent double precision) -> record151 1. ST_ApproxMinMax(rast raster, nband int, hasnodata boolean, sample_percent double precision) -> record 152 152 153 153 sample_percent: a value between 0 and 1 indicating the percentage of the raster band's pixels to consider when determining the min/max pair. … … 159 159 }}} 160 160 161 2. ST_ApproxMinMax(rast raster, ignore_nodata boolean, sample_percent double precision) -> record161 2. ST_ApproxMinMax(rast raster, nband int, sample_percent double precision) -> record 162 162 163 163 assumes that nband = 1 164 164 165 165 {{{ 166 ST_ApproxMinMax(rast, 2 0.01) 167 168 ST_ApproxMinMax(rast, 4, 0.025) 169 }}} 170 171 3. ST_ApproxMinMax(rast raster, hasnodata boolean, sample_percent double precision) -> record 172 173 assumes that nband = 1 174 175 {{{ 166 176 ST_ApproxMinMax(rast, FALSE, 0.01) 167 177 … … 169 179 }}} 170 180 171 3. ST_ApproxMinMax(rast raster, sample_percent double precision) -> record172 173 assumes that nband = 1 and ignore_nodata = TRUE181 4. ST_ApproxMinMax(rast raster, sample_percent double precision) -> record 182 183 assumes that nband = 1 and hasnodata = FALSE 174 184 175 185 {{{ … … 177 187 }}} 178 188 179 4. ST_ApproxMinMax(rast raster) -> record180 181 assumes that nband = 1, ignore_nodata = TRUE and sample_percent = 0.1189 5. ST_ApproxMinMax(rast raster) -> record 190 191 assumes that nband = 1, hasnodata = FALSE and sample_percent = 0.1 182 192 183 193 {{{