[GRASS-user] How to interpolate a gps trackpoint-"cloud" into a raster DTM

[Dylan Beaudette]

On Friday 02 November 2007, opopanax wrote:
> Hi List,
> I have two ascii files with points:
>
> way points:
> #N|E|Height|name
> 4416857|5359613|411|040
> 4416926|5359382|419|041
> 4416572|5358196|431|042
>
> and track points:
> #N|E|Height
> 4416930|5360187|407
> 4416921|5360166|408
> 4416914|5360153|409
> 4416900|5360127|409
>
> I imported them with v.in.ascii to vector layers
>
> cat tp.csv | v.in.ascii -z z=3 cat=0 out=tp_point01 columns='x double, y
> double, z double'
>
> cat wp.csv | v.in.ascii -z z=3 cat=0 out=wp_point01 columns='x double, y
> double, z double,label_name varchar(20)'
>
> Now first I want to interpolate them to raster files
> I used
> v.to.rast *p_point01 o=*p_p01_ras  u=z
> I couldn't keep the label 'name' in way points but I don't care.
>
> So how to hull the outer points in one area/mask to interpolate only the
> inner area
> ( I want to integrate this area in another DTM with r.mapcalc afterwards)
> I read about a command named s.hull but there are no site - 's.' -
> commands in my version (6.2.2 cvs on Ubuntu)
>
> And which command may the best to interpolate the model?
> r.surf.???
>
> Thx a lot for hints
>
> Om shantih
> Philipp

1. import files : v.in.ascii
2. optionally merge together: v.patch
3. compute convex hull(s): v.hull
4. interpolate: 
4a. set region extent and res: g.region
4b. interpolate with RST: v.surf.rst
5. patch into existing DTM: r.patch ?

Cheers,

Dylan




-- 
Dylan Beaudette
Soil Resource Laboratory
http://casoilresource.lawr.ucdavis.edu/
University of California at Davis
530.754.7341