Hi, I have a PNG library (524288 tiles of 256px * 256px) which I georeferenced via GDAL.
# This first part works correctly. • ullr: > ulx = (360 * (column / 1024)) - 180 > uly = 90 - (180 * (line / 512)) > lrx = ulx + 0.3515625 > lry = uly - 0.3515625 > ULLR = ulx + '' + uly + '' + lrx + '' + lry > gdal_translate -of VRT -a_srs EPSG:4326 -co NBITS=1 Path/Of/Input.png > Path/Of/Output.vrt -a_ullr + ULLR > > gdalwarp -s_srs EPSG:4326 -t_srs EPSG:3857 -co NBITS=1 Path/Of/Input.vrt > Path/Of/Output.tiff # The second part works correctly too I merge the tiles of a row (1024 TIFF tiles) using a VRT then from it I create the TIFF file > #!/bin/bash > > for i in `seq 0 1 511`; > do > gdalbuildvrt Path/Of/lines_vrt/map_$i.vrt Path/Of/tiff/map_11_*_$i.tiff > gdal_translate -co NBITS=1 Path/Of/lines_vrt/map_$i.vrt > Path/Of/lines_tiff/map_$i.tiff > done Here if I use gdal_merge.py, either I get an invalid file (1.xMo while the lines are approx 60Mo) or I observe a offset / deformation ... (In QGIS) # The last part doesn't work properly (and I don't know why ...) Here I am merging all the lines (TIFF files) into a global TIFF file using the same method as before. (with a list.txt file) > #!/bin/bash > > gdalbuildvrt -input_file_list Path/Of/lines_tiff/list.txt > Path/Of/global_vrt/map_global.vrt > gdal_translate -co NBITS=1 Path/Of/global_vrt/map_global.vrt > Path/Of/map_global.tiff and I observe a offset / deformation. (In QGIS again) I wonder what am I doing that is wrong My final goal is to use the global file (TIFF) with gdal2tiles.py (Tiles overlay on GMaps / OSM) Thanks _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
