Thanks for looking into this Matt! In my search I found this very helpful info for my situation: http://www.oryx.com/ams/landsat.html http://www.gdal.org/gdal_translate.html
The translated tiff produces color for me in the mapnik rendering process: gdal_translate -of GTiff -co "TILED=YES" mytiff.tif translated.tif On Tue, Jun 17, 2008 at 10:18 AM, Matt Hanson <[EMAIL PROTECTED]> wrote: > I looked more into this. Mapnik utilizes plugins for input which creates a > problem because there's no direct interface to the GDAL plugin. When you > open a GDAL file in Mapnik it goes through each band and checks the > GDALColorIntrep field for each RasterBand. If it finds a band set to each of > red/green/blue then you'll get an RGB band. If even one is missing you'll > get a grayscale image. Note that if color info is not set the grayscale > band used for rendering will always be the last band in the file. It's > during this time that the data is actually read in for these bands, so > there's no hope for setting color bands in styles as at that point it's too > late. I also noted that the entire datafile is read in for the bands on > open, the GDAL file handle is not kept around, simply read in and then > ditched. I don't think this is all that desirable because you are reading > in the file at full resolution (what if you have a 10Kx10K raster?) and only > downsized later during t he > rendering process. > > I think this is an inherent problem in Mapnik's design because it greatly > reduces its flexibility and has introduced some serious limitations. I'm > not sure the plugin method is the best approach especially with the existence > of the GDAL/OGR library there isn't a need for other plugins. The plugin > design should be replaced simply with a fixed dependency on GDAL/OGR. After > all GDAL fairly easily supports addition of custom formats so adding a format > to GDAL would extend to Mapnik. > > I'd like to do this but it'd likely be a large job and difficult due to the > general lack of documentation and comments. > > matt > > > > -----Original Message----- > From: Matt Bartolome [mailto:[EMAIL PROTECTED] > Sent: Monday, June 16, 2008 8:11 PM > To: Matt Hanson > Cc: [email protected] > Subject: Re: [Mapnik-users] GDAL raster rendering > > I'm going to try using tiffcp (libtiff-tools in ubuntu) to flatten the > geotiff and then manually set the extents. > > Hopefully someone can chime in and shed some light on the > gdal/geotiff/rastersymbolizer stuff. > > -Matt > > On Mon, Jun 16, 2008 at 3:02 PM, Matt Hanson <[EMAIL PROTECTED]> wrote: >> Hi Matt, great question! I say that because I've asked the same thing a >> couple times in the last week on both the user and dev lists (see my >> post from this morning). >> >> As near as I can tell mapnik gets the RGB bands when it reads in the >> image from the file itself, it's not set with the style. I hope I'm >> wrong though because it really should be adjustable. >> >> In your case I'm not sure\hy it's not setting them to the default RGB >> bands that are in the file itself - I had thought that if there were >> bands set in the file that's what it used but if it's not doing that >> either...I'm not sure. >> >> I keep looking at the code trying to figure this out but nothing >> yet....I'll post back here if I figure it out. Good luck! >> >> >> >> >> -----Original Message----- >> From: [EMAIL PROTECTED] >> [mailto:[EMAIL PROTECTED] On Behalf Of Matt >> Bartolome >> Sent: Monday, June 16, 2008 5:49 PM >> To: [email protected] >> Subject: [Mapnik-users] GDAL raster rendering >> >> Hi, >> I'm successfully rendering GeoTiffs using the GDAL datasource in gray >> scale but would like to render them in color. gdalinfo outputs: >> >> Band 1 Block=12001x1 Type=Byte, ColorInterp=Gray >> Overviews: 3001x2001, 1501x1001, 751x501, 376x251, 188x126, 94x63 >> Metadata: >> LAYER_TYPE=athematic >> Band 2 Block=12001x1 Type=Byte, ColorInterp=Undefined >> Overviews: 3001x2001, 1501x1001, 751x501, 376x251, 188x126, 94x63 >> Metadata: >> LAYER_TYPE=athematic >> Band 3 Block=12001x1 Type=Byte, ColorInterp=Undefined >> Overviews: 3001x2001, 1501x1001, 751x501, 376x251, 188x126, 94x63 >> Metadata: >> LAYER_TYPE=athematic >> >> All I've got in my style thus far is: >> >> <Style name="raster"> >> <Rule> >> <RasterSymbolizer> >> </RasterSymbolizer> >> </Rule> >> </Style> >> >> When viewing the geotiff in arcmap it sets Red, Green, Blue as >> 120,123,100 automatically. Is that something read off the file that >> gdal isn't seeing or is that something I set myself? >> >> Thanks, >> Matt >> _______________________________________________ >> Mapnik-users mailing list >> [email protected] >> https://lists.berlios.de/mailman/listinfo/mapnik-users >> _______________________________________________ >> Mapnik-users mailing list >> [email protected] >> https://lists.berlios.de/mailman/listinfo/mapnik-users >> > _______________________________________________ > Mapnik-devel mailing list > [EMAIL PROTECTED] > https://lists.berlios.de/mailman/listinfo/mapnik-devel > _______________________________________________ Mapnik-users mailing list [email protected] https://lists.berlios.de/mailman/listinfo/mapnik-users
