Hey Chris, On Nov 19, 2008, at 12:54 PM, Christopher Schmidt wrote:
> On Wed, Nov 19, 2008 at 12:36:56PM -0800, Michal Migurski wrote: >> Mapnik image output doesn't have a resolution - 96dpi or otherwise, >> it's just a number of pixels. >> >> You seem to be asking whether it's possible to generate output that >> is >> still legible when printed at a higher resolution. It's certainly >> doable but would require you to change your stylesheets: larger text, >> fatter lines, higher pixel size for map output, etc. A simple >> experiment would be to multiply every pixel dimension by 3 and see >> how >> that looks printed at 300dpi. >> >> I believe Mapnik also offers resolution-independent SVG and PDF >> output, but it's not something I've used before. > > The Stylesheets all use Scale, I think? Which is DPI dependant. So, if > you write a stylesheet for Mapnik -- and its assumption of DPI, since > you have to have one in order to calculate a 'scale' -- then you'll > need > to multiply all the scales by some number in order to have scales that > make sense. > > (This is why OpenLayers prefers 'resolution' -- map units per pixel -- > but for obvious reasons, that doesn't work well for something like > Mapnik.) > > Regards, > -- > Christopher Schmidt > MetaCarta Isn't DPI just a printing/ink term? I don't think Mapnik's map scale is DPI dependent. Perhaps I missing something, but the scale is simply calculated as the the current map width in geographic units/ pixel width. That would be the same as OpenLayers, right? http://trac.mapnik.org/browser/trunk/src/map.cpp#L382 Dane _______________________________________________ Mapnik-users mailing list [email protected] https://lists.berlios.de/mailman/listinfo/mapnik-users
