[GRASS-user] Creating raster from imported vector data

mort dod.mort at gmail.com
Tue Sep 26 18:56:33 EDT 2006


Hi All,
I'm new user of Grass and I try to convert my Mapinfo tab files into Grass
raster slope map.
The oryginal files were non-earth projection (kilometre grid) with isolines
stored in column "wysokosci_m".
I've created the new location: XY (unprojected) with nsres=7000 and
weres=5000, I've imported data into wysokosci2 vector layer:

GRASS 6.0.1 (nowa):~/grass/GRASSDATA > v.info -c wysokosci2
Displaying column type for database connection of layer 1:
INTEGER|cat
CHARACTER|id
DOUBLE PRECISION|wysokosc_m

In accordance to this book:
http://www.gdf-hannover.de/lit_html/grass60_v1.2_en/node64.html
I tried to convert isolines directly to surface using v.surf.rst:

v.surf.rst input=wysokosci2 layer=1 zcolumn=wysokosc_m dmax=1000.000000dmin=
825.000000 slope=slope2 zmult=1.0 tension=40. smooth=0.1 segmax=40 npmin=200


and I get:

Warning: there are points outside specified region--ignored 128 points
Warning: ignoring 27375 points -- too dense
WARNING: 39 points given for interpolation (after thinning) is less than
given NPMIN=200
Warning : there is less than 400 points for interpolation, no segmentation
is necessary, to run the program faster, set segmax=400 (see manual)
Loading data from attribute table ...
The number of points from vector file is 27542
The number of points outside of region 128
The number of points being used is 39

The output raster is one big yellow  square.I've also tried to decrease the
dmin but, in this case:

Points are too concentrated -- please increase DMIN

I'm not sure where I made mistake. I would be very thankfull for any help or
maybe existing guide,
TXH
Mort
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