[R-sig-Geo] GRASS and R question
jgreenberg at arc.nasa.gov
Sun Sep 10 00:22:43 CEST 2006
I was wondering if I could get some brief feedback on exactly what are the
capabilities of the sp and spgrass6 -- say I'd like to use R to calculate
and NDVI image (I know GRASS's mapcalc can do this fine, but I'm thinking of
some more complicated analyses that aren't easily performed in R and I
figured if I can figure out NDVI I can figure out the rest of them) -- Does
sp, spgrass6 and R itself provide both the data ingestion capabilities as
well as the necessary subsetting capabilities if my file is very large (e.g.
Can R do a per-pixel or per-line read/process/write routine, or will it
attempt to load an entire raster into memory)?
If R can deal with import of a multiband image and tiled processing, can
someone here perhaps post an example of how to accomplish the above task
(taking a 4 band large file, calculating NDVI and then writing out the NDVI
to disk) using R? Thanks!
Jonathan A. Greenberg, PhD
NRC Research Associate
NASA Ames Research Center
Moffett Field, CA 94035-1000
MSN: jgrn307 at hotmail.com
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