[daip] SDGRID convolution function

[Bob Garwood]

Glen Langston wrote:
> I appreciate your points.  Its a tough problem, but I think
> the thing to check is for the "divide by zero problem" in the
> sum of weights.    Maybe perform a quality control check on the
> sum(wt), not just on the individual input "wt" weights input
> to the grid.   If "sum(wt)" falls inside some +/-threshold, then
> those data should be flagged as well.   This check threshold
> could be a new parameter or threshold = max(wt)*reweight(2) (?).
> or something similar.
>
>   
I thought that's essentially what reweight(2) does.

-Bob