[R-sig-Geo] extract values to points

[Alexander Brenning]

Hi Frauke,

in the RSAGA package there is a function pick.from.ascii.grid which does
exactly what you want. Even works with large grids as it can process
them row by row. I use it for extracting point data from stacks of
Landsat bands, terrain attributes etc.

Here a case study (landslide susceptibility modeling):

http://www.environment.uwaterloo.ca/u/brenning/Brenning-2008-RSAGA.html

also available as pdf:
http://www.environment.uwaterloo.ca/u/brenning/Brenning-2008-RSAGA.pdf

I hope this helps

Cheers
    Alex


Frauke Barthold wrote:
> Dear list,
> 
> I have a soilmap as an Ascii grid and a dataframe with x and y
> coordinates (these are sampling points). I would now like to extract
> values from the soilmap to the dataframe based on location, the  x
> and y values. Is there any way to do this in R?
> 
> Cheers, Frauke
> 
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-- 
Alexander Brenning
brenning at uwaterloo.ca - T +1-519-888-4567 ext 35783
Department of Geography and Environmental Management
University of Waterloo
200 University Ave. W - Waterloo, ON - Canada N2L 3G1
http://www.fes.uwaterloo.ca/geography/faculty/brenning/