[R-sig-Geo] writeOGR KML question

[Roger Bivand]

On Wed, 13 Jun 2007, Bob Sutherland wrote:

> Hi,
>
> I read in polygon shape file and write the KML for GE using the writeOGR
> function
>
> tmpshpPoly<-readShapePoly("tmpshp",IDvar="AKUCU83_",
> proj4string=CRS("+proj=longlat"))
>
> writeOGR(tmpshpPoly, "test2.kml", "Location","KML")
>
> In the test2.kml file I'd also like to include a name for each polygon and
> some polygon shading.  I can edit the shape file and place or edit the tags
> but for this to work as we desire, I'd want to write the <name> tag with the
> tmpshpPoly$loc field.  I'd also like to color the polygon with a
> categorization of the tmpshpPoly$nAnimals field.  The categorization is
> easy.
>
> I am unable to write the <name> tag within the Placemark tag for each
> polygon.  I am also unable to alter the
> <PolyStyle><fill>0</fill></PolyStyle> fill color to an appropriate color.
> If you have suggestions I would be most appreciative.
>

The underlying driver is an OGR driver, and can only do as much or as 
little as OGR permits. If you are on Windows (please _always_ state 
platform, R and package versions from for example sessionInfo()), and have 
the latest rgdal, you have GDAL 1.4.1 code, that is the most recent 
release.

http://www.gdal.org/ogr/drv_kml.html

says:

"OGR has limited support for KML writing"

and there is no way to add the information you are interested in.

Could I suggest an alternative route, using the maptools functions: 
GE_SpatialGrid and kmlOverlay, which use the png() graphics device to 
write an image overlay of whatever you plot - so adding polygon fills, or 
labels, becomes as simple as plotting? Please see the GE_SpatialGrid help 
page.

Roger

> Thank you,
>
>
>
> Bob Sutherland
>
>
> 	[[alternative HTML version deleted]]
>
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-- 
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand at nhh.no