jamesmikedupont <at> googlemail.com <jamesmikedupont <at> googlemail.com> writes:
> > Lets see:The russian toplogical maps 24G ...But they are converted to tiffs so much bigger. I guess we could go back the ECW proprietary compressed jpeg.. but that needs special drivers. ECW is a fine format but it is a bit unclear if the license allows to use it for free on the server side even as an input image. It is probably OK but nobody seems to know for sure. What is sure is that it is not allowed to send out ecw from a server without ECW SDK license from Erdas. If disk space is a problem a rather good alternative is to use jpeg compression inside tiff. Mapserver works pretty fast with such tiff images. The command to use is like this: gdal_translate -of GTiff -co COMPRESS=JPEG -co PHOTOMETRIC=YCBCR -co TILED=YES -co JPEG_QUALITY=85 input.tif output.tif However, both ecw and jpeg compression gives some problems if images are warped and have nodata areas which are often written out as totally black or white pixels. After compression nodata areas are no longer uniformly black and marking pixels with RGB value of 0 0 0 as transparent does not work. As a result there will be some amount of very dark but not totally black pixels which will remain visible. However, this can be avoided by doing some mosaicing and cutting before compression. I can give some advice if needed, but perhaps OSM-dev is not the most suitable place for that. -Jukka Rahkonen- _______________________________________________ dev mailing list [email protected] http://lists.openstreetmap.org/listinfo/dev
