[GRASSLIST:4313] Re: s.surf.rst output extent

[Gordon Keith]

On Thu, 15 Aug 2002 18:58, Thomas Dewez wrote:
> Dear all,
>
> I am puzzled by the output extent of the s.surf.rst command and
> perhaps one of you would know how to solve the question.
>
> I have a sites file containing X, Y, and Z for about 2 million points
> (same old problem you've probably heard me moan about before). The
> DEM output always contains the interpolation of the north eastern
> corner of the file (1800 x 1120 cells). At first, I assumed the
> region was set wrong. I reset the region to the extent I wanted and
> still the output was identical.
>
> I'll try splitting the sites file in smaller sections but is there
> something I'm missing?

I've found the output of s.surf.rst contains values for quite a lot of 
area for which there is no data. 

Note the mapmask parameter to s.surf.rst.

When ever I import data I use s.to.rast first on the same data to create 
a map to use as a mapmask eg:


s.in.ascii in=accept.xyz sites=${survey}_accept

s.to.rast input=${survey}_accept out=${survey}_accept

s.surf.rst input=${survey}_accept elev=${survey}_bath tension=10 
zmult=-1 maskmap=${survey}_accept dmin=0.0001

r.mapcalc "${survey}_bath=if(${survey}_bath < -10, ${survey}_bath, 
null())"


The final step sets zero values to null as s.surf.rst also produces an 
interesting arrangement of zero and null values. (Note I'm working with 
mid-water bathymetry so all my values are < -10).

Regards
Gordon

-- 

Gordon Keith
Programmer/Data Analyst
Marine Acoustics
CSIRO Marine Research
http://www.marine.csiro.au

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