[OSM-talk] New atlas-generation program

Robert (Jamie) Munro rjmunro at arjam.net
Tue Mar 6 11:40:13 GMT 2007


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Tom Higgy wrote:
> Frederik Ramm wrote:
>> Why not go further down that route, first creating a 
>> similar "Print View" that will actually paste the tiles together 
>> on-the-fly
> 
> http://osm.bandnet.org/osm2jpeg/
> 
> A little buggy at the moment, as you might notice. Let me know of any 
> suggestions you have and I'll try and implement them sometime.

This is nice, but why does it output jpeg? jpeg just makes the edges go
blurry, and you get horrible artefacts when you look closely. Jpeg is
not designed for images where there are a limited number of colours in
large areas - these images compress well with a general compression
algorithm, like zip. Jpeg is designed for photographs and things like
photographs (screenshots of games etc.), where the probability of two
neighbouring pixels being identical is very small. That kind of image
doesn't compress well with a  normal compression algorithm, and the jpeg
artefacts don't show up.

Use PNG, it is the right solution for this kind of image

Robert (Jamie) Munro
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