Hi,
Perhaps you could try converting to postscript and then importing into
R with the grImport package? It seems a bit redundant (the postscript
is going to be converted back into some XML thing) but it might just
work for simple outlines.
Paul Murrell has a tutorial for this,
http://www.stat.auckland.ac.nz/~paul/R/grImport/import.pdf
(I haven't tried it for SVG pictures)
Hope this helps,
baptiste
On 11 Feb 2009, at 09:22, Hengl, T. wrote:
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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Baptiste Auguié
School of Physics
University of Exeter
Stocker Road,
Exeter, Devon,
EX4 4QL, UK
Phone: +44 1392 264187
http://newton.ex.ac.uk/research/emag
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