[GRASS-user] r.region and v.vol.rst parameters for Lat-Long location

HI all,

I was working with volume interpolation with nearly no problem following the GRASS documentation and the grassbook for a UTM location.

But working with a Lat-Long location is creating many doubts in my mind.

First, I don’t know v.vol.rst really works with Lat-Long, since all the examples I saw were in UTM location.

If yes, my location is:

RASS 6.4.0RC4 (Transect11):~ > g.region -p
projection: 3 (Latitude-Longitude)
zone: 0
datum: wgs84
ellipsoid: wgs84
north: 10:57:00.288311S
south: 11:03S
west: 78:49:12W
east: 77:45:13.757688W
nsres: 0:00:00.988219
ewres: 0:00:00.988219
rows: 364
cols: 3884
cells: 1413776

And I was setting t=0 b=-2200 tbres=20… to have 100 depths. But I don’t unterstand how should be res3, since I’m not using a UTM location. Should I convert, let’s say “10 meters” to decimal degrees, and using the result to set “dmin”?

Second, at v.vol.rst, I don’t understand how to set “dmin”? Is the same thing as above?

Basically I have a raster map with multibeam (bathymetry) along the 11 degree South parallel, and many CTDs measurements in the water column.

Please see here to understand what I mean: http://picasaweb.google.com/chris.for.lists/Map#5333477845413068514

I would like to create a slice (not exactly a volume) to show the CTD data over this 3D surface using nviz.

Thanks in advance for any help.

PS: I’m using GRASS 6.4.0 RC4.

Best regards,
Christian


Christian Ferreira
Oceanographer
IFM-GEOMAR Leibniz-Institute of Marine Sciences
Kiel - Germany

Poseidon Linux team
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