[mapserver-users] NoDATA value, transparency for paletted IMG file
Dear All, I'm trying to figure out how to set the OFFSITE value for an 8bit paletted img file - I've been searching the archive for quite some time now but couldn't find an answer :( I got the following gdalinfo: Driver: HFA/Erdas Imagine Images (.img) [..] Coordinate System is: GEOGCS["GCS_WGS_1984", DATUM["WGS_1984", SPHEROID["WGS_1984",6378137.0,298.257223563]], PRIMEM["Greenwich",0.0], UNIT["Degree",0.017453292519943295]] [..] Band 1 Block=64x64 Type=Byte, ColorInterp=Palette [..] NoData Value=0 Overviews: 7197x7624, 3599x3812, 1800x1906, 900x953, 450x477, 225x239 Metadata: [..] Color Table (RGB with 256 entries) 0: 0,0,0,255 1: 0,0,0,0 2: 0,0,0,0 3: 113,235,47,255 [..] so the NoData Value corresponds to index 0, with rgb 0,0,0 and opacity 255. In the mapfile I tried both OFFSITE 0,0,0 and PROCESSING "NoData=0" which didn't work. "OFFSITE 0", as one could expect, doesn't work either (generates an error). My output format is OUTPUTFORMAT NAME png DRIVER "GD/PNG" MIMETYPE "image/png" # IMAGEMODE RGBA IMAGEMODE PC256 EXTENSION "png" TRANSPARENT ON FORMATOPTION "transparent=on" END With my other RGB-Layers with 3bands the above setting works well, we're overlaying these WMS layers in the Google Earth API (browser plugin) using the function "ge.createGroundOverlay". We're using MapServer version 5.4.1 OUTPUT=GIF OUTPUT=PNG OUTPUT=JPEG OUTPUT=WBMP OUTPUT=SVG SUPPORTS=PROJ SUPPORTS=FREETYPE SUPPORTS=ICONV SUPPORTS=WMS_SERVER SUPPORTS=WMS_CLIENT SUPPORTS=THREADS SUPPORTS=GEOS INPUT=TIFF INPUT=EPPL7 INPUT=POSTGIS INPUT=OGR INPUT=GDAL INPUT=SHAPEFILE Any idea/clues what might be wrong here? Help is highly appreciated. Thanks and advance and greetings, Chris -- View this message in context: http://osgeo-org.1803224.n2.nabble.com/NoDATA-value-transparency-for-paletted-IMG-file-tp6305135p6305135.html Sent from the Mapserver - User mailing list archive at Nabble.com. ___ mapserver-users mailing list mapserver-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapserver-users
[mapserver-users] Re: NoDATA value, transparency for paletted IMG file
Dear Frank, dear all, thanks for your reply. I think I have narrowed down the problem and it isn't really a mapserver issue - the 8bit paletted img gets rendered to a 4bit-per-pixel png whereas the correctly transparent RGB img gets rendered to an 8bit-per-pixel png. Seems that the Google Earth API can't detect/deal with the NoData value in this 4bpp png and renders this value sort of "shaded black" (which I would like to get ridd of). GIMP for example can deal with the transparency in this 4bpp png. If I switch to RGBA in the output format, then I have the transparency however the image is much bigger: OUTPUTFORMAT NAME png DRIVER "GD/PNG" MIMETYPE "image/png" # IMAGEMODE RGBA IMAGEMODE PC256 EXTENSION "png" TRANSPARENT ON FORMATOPTION "transparent=on" END Is there a way I can force the mapserver to produce 8bpp pngs? THANKS for your help - highly appreciated - and greetings, Chris PS here's the gdalinfo output for the 4bpp png: Driver: PNG/Portable Network Graphics Files: lb_usa.png Size is 1024, 768 Coordinate System is `' Corner Coordinates: Upper Left (0.0,0.0) Lower Left (0.0, 768.0) Upper Right ( 1024.0,0.0) Lower Right ( 1024.0, 768.0) Center ( 512.0, 384.0) Band 1 Block=1024x1 Type=Byte, ColorInterp=Palette NoData Value=0 Image Structure Metadata: NBITS=4 Color Table (RGB with 9 entries) 0: 1,1,1,0 1: 0,0,0,255 2: 12,16,120,255 3: 31,62,140,255 4: 33,110,158,255 5: 42,156,154,255 6: 61,184,104,255 7: 59,214,45,255 8: 113,235,47,255 -- View this message in context: http://osgeo-org.1803224.n2.nabble.com/NoDATA-value-transparency-for-paletted-IMG-file-tp6305135p6312790.html Sent from the Mapserver - User mailing list archive at Nabble.com. ___ mapserver-users mailing list mapserver-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapserver-users
