We're interested in working within GRASS to do some spectral analyses,
but we need to be able to access a z-profile programatically, more or
less on a pixel-by-pixel basis (e.g. we don't think we can use r.mapcalc
to solve our problems). Here's a for instance, and let me know if this
is doable with existing commands and, if not, if there are standard
GRASS "z-profile" access techniques:
For an image of B bands (in grass, I think this is represented as
rastername.bandnumber), we want to calculate a weighted average of the
bands which are, say, the 5 highest values in the stack. Which 5 bands
are the highest will change from pixel to pixel.
On an array level, this is a sort function, but is there any algorithm
already built into GRASS that can deal with pixel-level sorting (and use
in mapcalc) and, if not, are there some good example code for access
pixel-by-pixel an image and performing some sort of function on this stack.
I hope this was clear enough. Thanks!
--j
--
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: [EMAIL PROTECTED], Gchat: jgrn307
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