Re: problem with subset one image by another

negra wrote:
....
> It's images processed from Level1 or Level 0 to Level 2 products. Some
> I take them from our receiving station, others, when we have problems
> with receiving, I take as 5-minute granules of data as Level 0 (pds)
> from ftp. Then I process them till level 2 product. And georefernce in
> IDL (because I have IDL routine for processing a large number of data)
> to geografical projection. And then I calculate indexes what I need.
> For example it's Vegetation, Snow, Dust and other calculations.
> For different arithmetic procedures in ENVI&IDL I must have same size
> images. May be it would be easier if I will subset by coordinates of
> four corner?
> But some times images smaller than the area of interest(AOI). Because
> AOI it's the territory of whole our country. In this case, I have
> procedure of filling by null data till needed size. But in future I
> plan to use this procedure (If I wrote it :-)) certainly) to smaller
> regions.

OK, that makes it a little bit clearer what you are doing. What we need 
is more details about what it is that you want to do, and haven't 
figured out how to do. What have you tried? What's wrong with the 
approaches you have tried?