Hi -
I am trying to run a script that calculates a common extent between two
images than then uses that extent to restrict the random selection of
cells from a raster using the sampleRandom function. For some reason it
doesn't seem to be working although it used to work. It appears as if
the "ext=TRUE" argument doesn't have an effect. The cells that are
returned cover the entire image and are not restricted to the area
defined by the "ext" variable.
Another thing I notiiced is that when I use "xy=TRUE" along with
"cells=TRUE" the resulting coordinates do not appear to match with the
cell numbers. When I use "xyFromCell" to calculate the coordinates of
the center of a cell returned from sampleRandom I get a good result but
it is different form the coordinates for that same cell returned from
sampleRandom.
I checked the extent and it looks fine.
Would someone be able to check if the extent feature in SampleRandom is
working in the Raster package. If someone thinks of something I'm doing
wrong please let me know.
Here is the line of code I am using:
sampleCells <- sampleRandom(predImage, size=numSamps, cells=TRUE,
ext=commonExt)[,1]
I'm using raster 2.1-25 with R 3.0 on Ubuntu 12.04 64 bit
Ned
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