[R-sig-Geo] Using adehabitat and splancs to achieve point-in-polygon analysis on raster?

[Sander Oom]

Dear Clement and Roger,

I send this email to you directly, because it concerns the link between 
Adehabitat and Splancs.

I have two sources of polygons:
- polygon shape files with areas of interest;
- polygons calculated using the home range methods in Adehabitat.
For the moment, each polygon source will only contain a single polygon.

I have one source of points: a grid representing NDVI values. I read the 
grid using the import.asc function in Adehabitat.

I would like to use both polygon sources to select the points in the 
NDVI raster which are inside the relevant polygons. Then I want to run 
several statistics (mean, standard deviation, etc) on the NDVI values of 
these points.

I intend to use the function inpip from Splancs, but it is not clear to 
me how I get the two polygon sources in the format used by Splancs.

Would you be able to point me in the right direction?

Thanks in advance for your help,

Sander.


-- 
--------------------------------------------
Dr. Sander P. Oom
Animal, Plant and Environmental Sciences,
University of the Witwatersrand
Private Bag 3, Wits 2050, South Africa
Tel (work)      +27 (0)11 717 64 04
Tel (home)      +27 (0)18 297 44 51
Fax             +27 (0)18 299 24 64
Email   sander at oomvanlieshout.net
Web     www.oomvanlieshout.net/sander