[GRASSLIST:1057] RE: srtm

[Gustavo Alcides Concheiro Perez]

Ian Macmillan escribió:

> Hi all, thanks for the suggestions.  I haven't tried them all, but they were all
> helpful for understanding how to do this stuff.  The one I finally used with
> incredible ease was a simple r.mapcalc using gtopo30 data.  
> 
> r.mapcalc newmap=if(isnull(gtopo30), gtopo30, srtm)

I thought of the same strategy but using GLOBE.  But then I thought that 
many hole HAVE information in the neighbouring cells in STRM, and that 
for small holes using just GLOBE would be loosing too much info, since 
the res for STRM is much better.  So I planned (haven't using it, for 
the unrelated problems I related of before),

if null:
	average of ((sum of neighbours at STRM) + GLOBE)

I don't recall the correct syntax for mapcalc, but you get the idea.  It 
will make an average of all non-null values in SRTM plus the one GLOBE 
value.  So the data is self-weighted: if the hole is big, GLOBE takes 
more weight, if its small, then the higher-res SRTM takes more weight.

What do you people think?


-Gustavo