[GRASSLIST:2935] numerically compare 2 rasters

dylan dylan at iici.no-ip.org
Sat Mar 13 22:59:21 EST 2004


i have 2 raster images that i would like to compare numerically. for the
time being, a simple linear regression would suffice.

these rasters are basically 84 selected points from a much larger raster
image - therefore there should only be 84 pixels that are not NODATA.

i have tried dumping the rasters as ascii, removing the NODATA values, and
setting up a table as follows:

raster1_values | raster2_values
v1             | v1
v2             | v2
...            | ...

however, when i plot the values i am getting very unusual results. it could
be that my plots are valid, but could i be doing something strange here?

thanks in advance,


"The world is a dangerous place to live; not because of the people who are
evil, but because of the people who don't do anything about it."
-Albert Einstein

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