[R-sig-Geo] Vector to raster?

[Jonathan Greenberg]

Thanks -- another few questions along these lines:

1) Is there any way to determine the type of vector file in advance of 
defining a layer name?  How can I list layer names affiliated with a 
given vector (it seems to be part of ogrinfo from the main gdal release, 
but when i do a ogrinfo(filename) I get yelled at to feed it a layer 
name first).
2) Is there a way to tell the feature type (point, polygon, line, 
etc...) of a readOGR object?
3) How do I get a polygon/line's node coordinates?  Using 
coordinate(readOGR(...)) I only get a single coordinates associated with 
each polygon/line in the vector.

Thanks!

--j 

Hengl, T. wrote:
>
> If you work with large shapes/grids, try also SAGA:
>
> > rsaga.get.usage(lib="grid_gridding", 3)
> SAGA CMD 2.0.3
> library path:   C:/Progra~1/saga_vc/modules
> library name:   grid_gridding
> module name :   Shapes to Grid
> ...
>
> But before SAGA, you need to reproject the polygons first (if necessary).
>
> see also some examples from:
> http://spatial-analyst.net/wiki/index.php?title=Export_maps_to_GE#Polygon_maps
>
> HTH
>
> Tom Hengl
>
> -----Original Message-----
> From: r-sig-geo-bounces at stat.math.ethz.ch on behalf of Paul Hiemstra
> Sent: Sat 2/14/2009 10:07 PM
> To: Jonathan Greenberg
> Cc: r-sig-geo at stat.math.ethz.ch
> Subject: Re: [R-sig-Geo] Vector to raster?
>
> Jonathan Greenberg schreef:
> > How do I take a polygon in some OGR supported vector layer (say, a
> > shapefile), and rasterize it given a pixel size and projection/datum?
> >
> > --j
> >
> Take a look at the spsample() function.
>
> Paul
>
> --
> Drs. Paul Hiemstra
> Department of Physical Geography
> Faculty of Geosciences
> University of Utrecht
> Heidelberglaan 2
> P.O. Box 80.115
> 3508 TC Utrecht
> Phone:     +31302535773
> Fax:    +31302531145
> http://intamap.geo.uu.nl/~paul <http://intamap.geo.uu.nl/%7Epaul>
>
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>

-- 

Jonathan A. Greenberg, PhD
Postdoctoral Scholar
Center for Spatial Technologies and Remote Sensing (CSTARS)
University of California, Davis
One Shields Avenue
The Barn, Room 250N
Davis, CA 95616
Cell: 415-794-5043
AIM: jgrn307, MSN: jgrn307 at hotmail.com, Gchat: jgrn307