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Hi, I've got a question when downloading svg files from openstreetmap. I was trying to download a map of an area in Marseille. The svg file I got was around 40MB when I set the scale at 1:20,000. But when I tried to download a map of a smaller scale, say 1:1,000,000, of the same area, I got an svg file of 120MB. I think that maps scaled smaller are more generalised, and the file size should be smaller as a result. Does anyone know why the file size actually increases when the scale is lowered? Any help is much appreciated. |
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The rendering engine behind the SVG export doesn't generalize or simplify geometries. It will drop some features - e.g. on a small scale map you won't see residential roads - but those features that you do see are drawn in full detail (even if that is not visible). Hence the large file. 2
AFAIK the text in OSM's SVG exports is converted to vector geometry, I think this is probably the biggest contributing factor in the size. If you need more compact SVGs, you can use Maperitive's export function.
(01 Mar '13, 12:31)
Breki
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... or have a look at http://wiki.openstreetmap.org/wiki/SVG in general
(01 Mar '13, 18:58)
stephan75
Thank you all... But I am still confused why the size of the svg file downloaded under a smaller scales is larger, given a same area. At least, the sizes of svg files downloaded from different scales should be almost the same. For a same polygon, I got a svg file of 120MB for a map scaling at 1:500,000 but got a file of about 30MB for a map of the same polygon scaling at 1:50,000......
(04 Mar '13, 09:10)
weeburn
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