Hi, The encoding system does not care if the source data presents DEM or something else. Also, it does not need to be restricted to RGB. I tried to find similar use cases and it looks like encoding 32 bit floats into RGBA (or RG for 16 bits) was used with WebGL shaders when floats were not supported natively. See for example https://www.shadertoy.com/view/WsVGzm, https://gamedev.net/forums/topic/630239-encode-float-to-rg-or-rgb/, https://github.com/equinor/glsl-float-to-rgba
-Jukka Rahkonen- ________________________________________ Lähettäjä: gdal-dev <[email protected]> käyttäjän Andrey VI via gdal-dev <[email protected]> puolesta Lähetetty: Perjantai 9. tammikuuta 2026 9.02 Vastaanottaja: rayg <[email protected]> Kopio: gdal-dev <[email protected]> Aihe: Re: [gdal-dev] Support for Terrain-RGB Why not just "rgb-dem", i.e. "RGB encoded DEM"? Friday, January 9, 2026 3:16 AM +03:00 from rayg via gdal-dev <[email protected]>: Maybe call it "scalar-rgb"? Because ultimately what the encoding does is use the color channels to hold a single value. It doesn't even have to be for elevations at all. Could also add swizzle options in case BGR or some other order is used. And include the alpha channel just in case, but also let alpha be alpha if needed. If e.g. "A" is left off from the swizzle option, then it's an actual alpha channel. More general would be scalar encoding of any multichannel (multiband) file, e.g. YCbCr, HSV, CMYK, etc. Ray On Thu, 8 Jan 2026 at 1:13 PM Even wrote:> > There's nothing especially terrain (or topography) about this afaics, > and utility seems like the right approach rather than creating a > format variant. Actually Frédéric's intersting remark abou potential usage with "gdal raster tile" would actually make the driver approach a better choice.... unless we would extend "gdal raster tile" to accept a pipeline to go to create a final tile from a 'raw' one, like 'gdal raster tile --tile-pipeline="read ! encode-rgb --offset=-10000 ! write --of PNG" --extension png in.tif out_directory' . But a ENCODE_RGB driver approach is more simple than implementing that. Even -- http://www.spatialys.com My software is free, but my time generally not. _______________________________________________ gdal-dev mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/gdal-dev [X] _______________________________________________gdal-dev mailing [email protected]https://lists.osgeo.org/mailman/listinfo/gdal-dev--Andrey _______________________________________________ gdal-dev mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/gdal-dev
