[Geotools-gt2-users] masking a grid coverage

[Michael B. <mic...@gm...>]

Hi all,

In my app I have two single band grid coverages, one with double
values and one with integer values.  For each grid cell in the first
coverage I want to calculate the sum of values within a given
distance, using the second coverage as a mask (ignore pixels with
value <= 0).  Finally I want to binarize the result of the convolution
with a given threshold value.

I'm wondering what the most efficient way to do this is.  At present I
have code working that does the above steps without masking. It makes
use of JAI's ConvolveDescriptor class to sum neighbourhood values,
then the ImageWorker class to binarize the result.

To add masking to the process I guess I start out by creating a JAI
ROI object from the RenderedImage derived from the second coverage.
But after that I'm a bit stuck as to how to use the ROI in the
convolution stage, other than the naive approach of creating a new
input image with, for instance, TiledImage.set(img, roi).

I wonder if anyone can suggest an approach ?  Also, am I overlooking
any Geotools class methods that would do some or all of the above
without resorting to JAI directly ?

Any help much appreciated.

Michael