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Re: [ccp4bb]: real space difference map?



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Mapman can subtract maps (or rather add them after multiplying one by 
-1 or appropriate negative scale factor), provided the cell param and
grid of the two maps are the same. For this to make sense you have to
have corresponding parts of the density in the two maps superimposed.
If you can get an approximate operator taking density in one cell to 
corresponding density in the other, then improve the operator with
MAVE option IMP, then use MAVE or mapmask to cut out density inside a 
mask and "skew" it into position in the second cell (with same cell
param, grid, and extent as your fourier map in the second cell), then
you can use mapman to subtract the two to make a difference map.

Good luck,
Ed

Peter Nollert wrote:
> 
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> 
> Dear all,
> 
> I'd like to compute a difference map, problem is
> that one dataset is in C2221 and the other in P63.
> I guess there's no way to do a difference fourier
> (fo-fo). But it should work in real space.
> How do I calculate a real space difference map?
> 
> Thanks,
> Peter