Mark, I've tried to incorporate your feedback in this changeset:
@@ -173,6 +173,16 @@ the PROJ, DATUM or UNITS with SetMetadataItem(), the later values will override the values built from the projection string.<p> +All those can for example be modified with the -a_ullr, -a_srs or -mo switches +of the <a href="gdal_edit.html">gdal_edit.py</a> utility.<p> + +For example: +<pre> +gdal_edit.py -mo DATUM=WGS84 -mo PROJ=GEODETIC -a_ullr 7 47 8 46 test.ecw + +gdal_edit.py -a_srs EPSG:3068 -a_ullr 20800 22000 24000 19600 test.ecw +</pre> + <h3>File Metadata Keys: </h3> <ul> @@ -190,7 +200,12 @@ <li>COLORSPACE <li>COMPRESSION_DATE <li>COMPRESSION_RATE_ACTUAL -<li>COMPRESSION_RATE_TARGET +<li>COMPRESSION_RATE_TARGET. This is the percentage of the target compressed +file size divided by the uncompressed file size. This is equal to +100 / (100 - TARGET) where TARGET is the value of the TARGET +creation option used at file creation, so a COMPRESSION_RATE_TARGET=1 is +equivalent to a TARGET=0 (ie no compression), COMPRESSION_RATE_TARGET=5 is +equivalent to TARGET=80 (ie dividing uncompressed file size by 5), etc... <li>VERSION </ul> Even > 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 -- Spatialys - Geospatial professional services http://www.spatialys.com _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
