[OSGeo-Discuss] Proposal: OSGeo Cartographic Library

Ari Jolma ari.jolma at tkk.fi
Tue Apr 15 08:53:19 PDT 2008

Frank Warmerdam kirjoitti:
> In my opinion we would be better off starting with a widely accepted
> standard like SLD as a basis of a feature styling standard

I'm right now looking at SVG. It is a full graphics description 
language, but maybe the styling information could be somehow picked out 
an reused for our purposes. SVG is becoming more popular and for example 
many symbol sets (also mapping symbols) are already in SVG. Thus we'd 
also need tools for parsing SVG.

If the stylings that are distributed with geodatasets are SVG, then 
producing SVG maps would be easier, wouldn't it?

I'm using Cairo, so I looked for SVG -> Cairo tools. It seems that 
Firefox does exactly that, but the functionality is deep in its code and 
not a separate library. Other SVG->Cairo libraries seem to have died. I 
haven't looked at SVG->AGG, SVG->Qt or others.

I've been able to whip up a very simple SVG to Cairo parser + renderer 
in few hours (with Perl ;) but the SVG specs are rather large and 
permissive for all kinds of funny things, which make parsing a bit of a 
problem -- although it is XML. But what I made is good for simple symbols.

Cairo can produce SVG, so that's not a problem.

SVG styling documents are here: http://www.w3.org/TR/SVG11/styling.html



Prof. Ari Jolma
Geoinformatiikka / Geoinformatics
Teknillinen Korkeakoulu / Helsinki University of Technology
tel: +358 9 451 3886 address: POBox 1200, 02015 TKK, Finland
Email: ari.jolma at tkk.fi URL: http://www.tkk.fi/~jolma

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