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Updated RasterSymbolizer (markdown)

springmeyer 2012-09-25 09:44:14 -07:00
parent 18f00e4586
commit 58dc58d19e
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RasterSymbolizer.md

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<!-- Name: RasterSymbolizer -->
<!-- Version: 19 -->
<!-- Last-Modified: 2010/03/12 07:06:11 -->
<!-- Author: albertov -->
# RasterSymbolizer
The RasterSymbolizer is used to render an image from any [GDAL supported format](http://www.gdal.org/formats_list.html) using the [[GDAL]] plugin or from GeoTiff's using the [[Raster]] plugin.
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| *parameter* | *value* | *description* |
|--------------|---------|-----------|
| opacity | 0.0 - 1.0 | 1 is fully opaque while zero is fully transparent and .5 would be 50% transparent |
| mode | grain_merge, grain_merge2, multiply, multiply2, divide, divide2, screen, hard_light | Compositing/Merging effects with image below raster level (?). The formulas for combinding foreground (raster) and background are: grain_merge: bg + fg - 0.5, grain_merge2: bg + 2*fg - 1.0, multiply: fg * bg, multiply2: 2 * fg * bg, divide: bg / fg, divide2: 2*bg / fg, screen: (1-fg)*(1-bg), hardlight: see [[http://docs.gimp.org/en/gimp-concepts-layer-modes.html#id2834930]] |
| comp-op (previously called `mode` in <= Mapnik 2.0.x) | grain_merge, grain_merge2, multiply, multiply2, divide, divide2, screen, hard_light | Compositing/Merging effects with image below raster level (?). The formulas for combinding foreground (raster) and background are: grain_merge: bg + fg - 0.5, grain_merge2: bg + 2*fg - 1.0, multiply: fg * bg, multiply2: 2 * fg * bg, divide: bg / fg, divide2: 2*bg / fg, screen: (1-fg)*(1-bg), hardlight: see [[http://docs.gimp.org/en/gimp-concepts-layer-modes.html#id2834930]] |
| scaling | fast, bilinear, bilinear8 || fast: nearest neighbour, bilinear: bilinear interpolation for all 4 channels (RGBA), bilinear8 like bilinear, but only one channel assumed |