id summary reporter owner description type status priority milestone component version severity resolution keywords cc 4645 gdal_translate fails on GRD grid mladen warmerdam "'''NOTE''': This is probably not gdal_translate specific, but rather a bug in the Northwood Vertical Mapper .grd driver. However, I didn't want to jump to conclusions and so am describing exactly how I came across the issue, which was with gdal_translate. Suppose we start with a large, mostly empty grid (45Mb zipped, ~4Gb unzipped): http://dl.dropbox.com/u/53500018/translateBug/original_30m_grid.zip This grid has a resolution (pixel size) of 30m, and looks like this when I open it in a viewer: http://dl.dropbox.com/u/53500018/translateBug/original.png However, if I try to translate it with ""gdal_translate"", with the following command: {{{ gdal_translate -of png -b 1 -b 2 -b 3 -outsize 10% 10% ""original30m.grd"" resolution30.png }}} I get garbled, warped output near the bottom of the grid:[[BR]] http://dl.dropbox.com/u/53500018/translateBug/resolution30.png It is evident also that a large chunk of the grid has been cut off at the bottom. This seems to be related to the large file size of the original grid, because I can downsample it to lower resolutions, and the lower the resolution, the better the output. For example: Downsampled to '''35m''':[[BR]] http://dl.dropbox.com/u/53500018/translateBug/resolution35.png '''37m''' (notice that less is cut off at the bottom, but still warped):[[BR]] http://dl.dropbox.com/u/53500018/translateBug/resolution37.png By '''45m''', it looks OK, but I doubt that it would look OK if there were data near the bottom of the grid extent.[[BR]] http://dl.dropbox.com/u/53500018/translateBug/resolution45.png And by '''60m''', everything is clearly fine:[[BR]] http://dl.dropbox.com/u/53500018/translateBug/resolution60.png For convenience, here is the original grid downsampled to 60m resolution (22Mb zipped, ~1Gb unzipped):[[BR]] http://dl.dropbox.com/u/53500018/translateBug/resized_60m_grid.zip Rather than resizing, I can also cut the original grid in 2 halves, and get good output. Unfortunately, I can't do this in every case, since I'm using GDAL as part of an automated process. So, obviously the wheels fall off somewhere around 2 Gb grid size, or 45m resolution in this case. The 30m is a good sample grid for the ""bad"" case, and the 60m is a good sample for the ""good"" case, but if more samples are needed let me know. '''P.S.''' The aux.xml files for each of the PNGs above are available just by adding "".aux.xml"" to the link (except original.png, which is a screen cap)." defect closed normal 1.9.1 GDAL_Raster 1.9.0 major fixed grd, vertical mapper, northwood, gdal_translate