Hello again,I think I found the cause of my problem - on my server (where I had preprocessed all of my imagery), I have libgeotiff-1.2.4 installed from the F8 repositories. On my laptop I had libgeotiff-1.2.3 installed from source. I upgraded my laptop to libgeotiff-1.2.4 (I tried 1.2.5, but it didn't compile for me), and recompiled gdal and mapserver. Now it seems that imagery renders okay (after some quick tests). I didn't realize I had different libgeotiff library versions...but it also hadn't occurred to me that a GeoTiff dataset might be incompatible with different versions of libgeotiff.
So should I maybe close the ticket that I opened earlier today? Mike Mike Leahy wrote:
Ok, I'll file a ticket shortly...but I have a few more things I've tried that might add insight to this. It seems if I load the map via cgi mapserver, I get the same problems - so this isn't limited to mapscript. In contrast, I don't seem to have any trouble with the output values if I extract a single pixel from an image using gdal_translate to a *.grd file (at the same coordinates where I get corrupt results from mapscript/mapserver) - so the problem doesn't seem to be with gdal by itself.Also, I can point out that the corrupted areas in the output have no coincidence with tile-index boundaries. I say this out because if I render a layer from a non-tiled image dataset, the corrupted areas appear as horizontal bands across the entire width of the image output, rather than rectangular areas (though my non-tiled dataset is a single-band floating-point DEM, rather than an rgb image). However, as before, the height and number of lines of each band is variable.Maybe it's just time to upgrade my OS (F7 is EOL after all). Regards, Mike Tamas Szekeres wrote:Mike, It's quite difficult to find out what's going on. You should file a ticket including the example and sample data. Probably the problem may be reproduced in other machines as well. Best regards, Tamas 2008/8/19 Mike Leahy <[EMAIL PROTECTED]>:Tamas,I just gave this a try a few times - deleted the cache, and loaded one tile. It seems to happen less frequently, but I still have about a 1 in 3 chanceof getting various rectangle artifacts on the image. It basically looks like something forgets to draw one or more of the rgb colours. Mike Tamas Szekeres wrote:Mike, Did you experience the same problem when calling tile.php directly when rendering an individual tile? Best regards, Tamas 2008/8/19 Mike Leahy <[EMAIL PROTECTED]>:Hello list,I'm wondering if anyone can help me figure out a problem I'm having with corrupted output from from a tiled geotiff dataset I'm using in a ka-Mapenvironment. You can see what's happening to the imagery here: http://img527.imageshack.us/my.php?image=corrupthd1.pngThis generally happens when I'm zoomed in fairly close, and usually with this high-resolution image dataset. However, I can get corrupted outputforother raster datasets (all geotiff, but not always tiled). It seems tohappen when the machine is processing most intensively (i.e., usually whenthe imagery is being rendered by ka-Map). It also seems to be limited to the laptop I am using, which is running F7-x86_64. In contrast, I havean actual server (F8-x86_64), which has a virtually identical setup (with respect to MapServer and its various dependencies), but with lots more cpu cores and ram, and it's having no trouble at all (as far as I have noticed).The corruption in the output from the same application my laptop is notalways the same - if I clear the cache for ka-Map and re-render the images, I'll get similar artifacts appearing in the output (red, green, blue and/orblack rectangles), but they will vary in size and location. It happensfor both GD/AGG drivers, and JPEG/PNG output formats. Until now, I figured it was just a problem with limited memory on my laptop(it was always around 100% when rendering this imagery on the web service+ viewing the application in a browser), but now I've upgraded the ram -there's plenty of spare room and I'm still getting the same problem. Ijust finished upgrading Gdal from 1.5.0 to 1.5.2, and that didn't help any.Basically, the only real differences I can think of between my laptop andmyserver are the number of cpu cores (1 on my laptop vs. 8 on the server),andpossibly the versions of some of the underlying libraries in the system. Does anyone know where I should start looking to find the cause of this? Or perhaps somebody recognizes this problem, and knows what I might bedoing wrong... Thanks for any suggestions, Mike _______________________________________________ mapserver-users mailing list mapserver-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapserver-users
_______________________________________________ mapserver-users mailing list mapserver-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapserver-users
