Hi Benjamin, Am Mittwoch, 23. März 2011, um 15:14:58 schrieb Sisyphos: > @Holger: Are there for each > zoomlevel individual raster layers/files used?
No, I prepare a raster for the most detailed zoom level, and include that as one layer in the mapnik style. This might not be optimal concerning rendering speed, but so far that was not a problem for me. > 1. My files are not as nice as Hogleres files are. What would you > suggest to smooth them. Is it possible to smoth them using gdal? Or is The mentioned renderings are based on CIAT/CGIAR hole-filled SRTM data (as that data has an incompatible license wrt. CC BY SA, the page was meant to not be public, and I sent the email to you in private intentionally; unfortunately I forgot to mention, that it should not be made public ...). The quality would usually not be sufficient to the highest zoom levels I use. Actually, what I do with them, is a kind of smoothing, as you also propose. gdalwarp has the ability to resample that data. Even though this does not make the data "more realistic" of course, moderate resampling can make maps look much nicer, and usually is not too far off, in my experience. > it possible with mapnik symbolizers -- maybe according to zoom levels. > 2. It seems that I'll have Thousands of Tiff-files for maybe two or > three zoom levels (I hopw I'll be able to create a suitable TFW-Files > for them); what would you suggest to work with them with mapnik? I use gdal_merge.py to merge them into one file; this at least eases handling (if the individual files are tiled, or part of one file being hidden by another is not a problem). Altogehter, my workflow concerning raster images looks something like this (for source images in EPSG4326 lat/lon projection, and target srs [the one used for the rendered mapnik map] being spherical mercator): gdal_merge.py -v -o <outfile> -ul_lr <left> <top> <right> <bottom> <image1> <image2> ... gdal_translate -of GTiff -co "TILED=YES" -a_srs "+proj=latlong" -projwin <left> <top> <right> <bottom> <infile> <outfile> gdalwarp -of GTiff -co "TILED=YES" -srcnodata 32767 -t_srs "+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +no_defs +over" -rcs -order 3 -multi -wt Float64 -ot Float64 -wo SAMPLE_STEPS=101 -tr 30 30 -multi <infile> <outfile> I need the Float64-conversion for the really high zoom levels and hill shading, where height-differences of one meter would create "steps" instead of elevation gradients. Actually I am not sure anymore, why I introduced the middle step (gdal_translate), but as this works fine, I do not have an incentive to change my workflow just now ... Yours, -- Holger Schoener [email protected] _______________________________________________ Mapnik-users mailing list [email protected] https://lists.berlios.de/mailman/listinfo/mapnik-users
