Back from week-end, sorry for interrupting the conversation. I tried setting a -a_nodata 255 value before creating the pyramid, the result is exactly the same as with black nodata or without a nodata value. The nodata value of the original geotiffs is ignored.
> First an image is created, large enough to hold the tile and its > neighbors from level x-1 > Is it possible this image has a black background color ? > Third, the scaling takes place. > I guess the black background is interpolated with the border data and produces nearly black pixels. > The problem is, sometimes neighbors are missing, right ? > Right : my source data is not a rectangle. > Do you have this problem already at level 1 or beginning with level 2 ? > Curiously, it starts at level 3. At levels 0, 1 and 2, the black remains #000000 > Do you start from one big image or an already tiled image ? > My source data is made of several geotiff images. In the past, I generated the same pyramid and didn't have this problem. The parameters that changed are : -pyramidOnly in the past, now no more -ps 10000 10000 in the past, now 4096 4096 -co COMPRESS="LZW" in the past, "JPEG" now - GDAL 1.6.0 in the past, now GDAL 1.7.2 The command I use now is : gdal_retile.py -targetDir ../pyramid4096/ -levels 12 -v -s_srs /mnt/webgisdata/geoserver/config/3812.prj -ps 4096 4096 -r bilinear -co "COMPRESS=JPEG" -co "TILED=YES" -co "INTERLEAVE=PIXEL" -tileIndex orthocol -tileIndexField location *.tif & I gave a shot with LZW compression and the problem is gone away. But the output data is 4 GB instead of 800 MB with JPEG compression. Do you think I should use LZW compression ? -- View this message in context: http://osgeo-org.1803224.n2.nabble.com/gdal-retile-and-nodata-tp5079895p5097462.html Sent from the GDAL - Dev mailing list archive at Nabble.com. _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
