
Dear list,

I discovered recently that Wikipedia has an extensive list of various administrative/political/thematic/historic maps (which are regularly updated!):

http://en.wikipedia.org/wiki/Wikipedia:Blank_maps

The maps are provided in PNG and SVG (Scalable Vector Graphics) formats. The later being recently promoted as the most prefer format for web-graphics (I completely agree). The SVG format is a type of XML, thus it can be directly read to R using the XML package. If I look at the elements of e.g. http://upload.wikimedia.org/wikipedia/commons/0/03/BlankMap-World6.svg map, I can see that a polygon is coded as: 

----------------------------------------------
...
<g id='fr'> 
		<g class='landxx coastxx fr fx' id='fx'> 
			<path d='M 1258.5363,351.42953 C 1258.2153,351.09353 1257.8553,350.80453 1257.4563,350.56553 C 1257.5503,351.13153 1257.9293,351.52653 1258.5363,351.42953' id='path2166'/>
...
----------------------------------------------

which is some small polygon of France. So these are obviously coordinates (the Robinson projection system) of the nodes of that polygon and "id" is it's unique ID.

The issue is how to read a SVG into a GIS/R (see also http://wiki.svg.org/GIS_in_SVG)? I could not find any 'easy way' do this, although it seems that conversion SVG to GML and then to OGR formats should go easy. I guess that it should not be too complicated to sort all polygons and create a "SpatialPolygonsDataFrame". Did anybody already try something similar?


Thanks!

Tom Hengl
http://spatial-analyst.net 

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