2009/10/19 Andy Robinson (blackadder-lists) <[email protected]>: > Steve Hosgood wrote: >>Sent: 19 October 2009 9:39 AM >>To: [email protected] >>Cc: 'josm-dev' >>Subject: Re: [OSM-dev] Out of copyright WMS offering - looking for >>assistance >> >>Must they be .jpgs? You'll get a lot of "sharp edge" artefacts using the >>.jpg format on a map. In theory at least (and in practice whenever I've >>done it) .png will give better results on material such as that. >> > > Bear in mind these are printed maps, not rasterised vector maps. We tried > with png but you can get much lower file size without loosing too much > definition with the jpg's. > > Now, if someone wants to spend the time proving me wrong they are welcome to > a an original scan to try it.
I assume you've run something like optipng [1] over the images. I've found with complex images you can get quite a size decrease with 'optipng -o7 *.png'. However, if the size of the images at present is ok, there's no need to change anything. The quality looks fine as it is. On another note, in my tests I managed to reduce the size of the default Mapnik tiles by about 5% but I guess that reduction is small since they've already been slightly optimised. -- Matt Williams http://milliams.com [1] http://optipng.sourceforge.net _______________________________________________ dev mailing list [email protected] http://lists.openstreetmap.org/listinfo/dev
