While writing this, I figured put most of the problems, so this note will be more about suggestion in making the documentation more usable.
I am going to receive an amount of ecw files that, for whatever reason, do not contain the georeferenced information. For the first image received, gdalinfo shows the following: Driver: ECW/ERDAS Compressed Wavelets (SDK 3.x) Files: 1989.423C_42348.5000.ecw Size is 8001, 6001 Coordinate System is `' Metadata: COLORSPACE=GREYSCALE COMPRESSION_RATE_TARGET=5 VERSION=2 Corner Coordinates: Upper Left ( 0.0, 0.0) Lower Left ( 0.0, 6001.0) Upper Right ( 8001.0, 0.0) Lower Right ( 8001.0, 6001.0) Center ( 4000.5, 3000.5) Band 1 Block=256x256 Type=Byte, ColorInterp=Gray Description = Grayscale Overviews: 4000x3000, 2000x1500, 1000x750, 500x375, 250x187 Since I know the position, I did the following: 1) gdal_translate -of GTiff -a_nodata 135 -a_srs EPSG:3068 -a_ullr 20800 22000 24000 19600 1989.423C_42348.5000.ecw 1989.423C_42348.5000.3068.tif 2) gdal_translate -of ECW -co TARGET=0 -a_srs EPSG:3068 1989.423C_42348.5000.3068.tif 1989.423C_42348.5000.3068.tif.ecw gdalinfo now shows the projection information. - but with 'COMPRESSION_RATE_TARGET=1' instead of 5 -- no doubt due to the '-co TARGET=0' (which I have no idea what it means) gdal_translate has a note with the '-co' 'See format specific documentation for legal creation options for each format' a: <a href="http://www.gdal.org/formats_list.html";>See format specific documentation for legal creation options for each format</a> which then leads to http://www.gdal.org/frmt_ecw.html - where TARGET is then explained (percentage) -- but no explanation on what 'COMPRESSION_RATE_TARGET' is ---> '-co TARGET=50' (percent) = 'COMPRESSION_RATE_TARGET=2' ---> '-co TARGET=75' (percent) = 'COMPRESSION_RATE_TARGET=4' ---> '-co TARGET=99.99' (percent) = 'COMPRESSION_RATE_TARGET=9997' A comparison chart would be useful here - comparing what gdalinfo shows to what gdal_translate needs (I still do not know what TARGET setting is needed to get COMPRESSION_RATE_TARGET=5) What I would like to know is: can gdal_edit.py be used to achieve the same result? - base on another found sample, I worked this out, since I have never used the combination -a_srs/-a_ullr before -- wasted a lot of time in the past creating a world-file for this task gdal_edit -a_srs EPSG:3068 -a_ullr 20800 22000 24000 19600 1989.423C_42348.5000.ecw So for both 'gdal_translate' and 'gdal_edit' a practical sample to set the missing georeferenced information would be useful - while searching I saw a lot of reports of people receiving ecw file 'raw' and wondering how to get it in Once one knows it, it is easy But it has be hours since I found this sample: gdal_edit -mo DATUM=WGS84 -mo PROJ=GEODETIC -a_ullr 7 47 8 46 test.ecw and trying to adapt it to work with a non-wsg84 system. Mark Johnson, Berlin Germany
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