[R-sig-Geo] Slope and Aspect calculations in R

[Josh London]

Thanks for the suggestions so far regarding the use of GRASS or SAGA.

We have considered those options but SAGA doesn't appear available for 
MacOS. My understanding is that spgrass6 is more for accessing R 
code/functions from within GRASS vs accessing GRASS functions from 
within R. We have all our other analysis coded up in R, and just need 
these functions to do one part of a bigger process. Maybe I'm 
misunderstanding how to use R and GRASS together. I'll do some further 
research.

Thanks again
Josh

Josh London wrote:
> Hello
> 
> We are looking to mimic, in R, the slope (max magnitude difference 
> between a cell and its neighbors) and aspect (direction of maximum 
> magnitude difference) functions found in ESRI's Spatial Analyst package. 
> We were just about to code up the slope function but thought I would 
> make sure we weren't re-inventing any wheels already out there.
> 
> Thanks
> Josh
> 

-- 
Josh M. London, PhD

Wildlife Biologist
Polar Ecosystem Program
National Marine Mammal Lab
Alaska Fisheries Science Center, NOAA Fisheries
Seattle, WA

The contents of this message are mine personally and do not
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National Oceanic and Atmospheric Administration.