Hi, You may be able to do that with the Saga grid mosaic. You can select ´max’ for overlapping areas.
http://www.saga-gis.org/saga_tool_doc/2.3.0/grid_tools_3.html Nicolas > Le 17 nov. 2017 à 15:05, Rousseau Lambert2, Louis-Philippe (EC) > <[email protected]> a écrit : > > Hi everyone, > > I would like to have your opinion on some processing I have to do. > > So I have to merge many rasters (eventually more then 50). Some overlaps > (never completely), but others don't, my files when merged cover Canada. > I have to keep the maximum value where there is some overlap between > different files. > > My first try was to use gdal_calc with --calc="maximum(A,B)", but it can > only input 26 files at a time. And The output of gdal_calc is only the > region of overlap, in my case I have to keep the whole extent of my > rasters, not only the region of overlap... Is there a way I could use > gdal_calc and keep everything, not only the overlap? > > My second try was to use gdalwarp with a vrt of all my files as input > and use -r max for my resampling. My results were that it only > overlapped my geotiff and did not took the maximum value. > > My last try, was to use gdalwarp to ensure that all my files have the > same extent and that pixel overlap perfectly. Then I create a mosaic > using gdal_merge of all my rasters. At this point I don't manage yet the > maximum value. Then I loop trough all my geotiff using gdal_calc to > output the overlap region between one geotiff and my mosaic. then I can > merge the overlap region with my mosaic. Finally I get a mosaic of the > maximum value where my raster overlap. > > I don't really like this solution because if I have 50 files, I have to > use gdal_calc 50 times and merge the result 50 times... That seems a lot > of processing to simply get the maximum value in a mosaic. > > Can you think of a better way to do? Any thoughts or opinions are welcome! > > Louis-Philippe R. Lambert > > _______________________________________________ > gdal-dev mailing list > [email protected] > https://lists.osgeo.org/mailman/listinfo/gdal-dev
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