georgew wrote:
Micha, I followed your instructions with the following results:
----
Import data from 2 shapefiles, Contour (layer 1)and Track (layer 2): (no
problems reported)
v.in.ogr dsn=/home/george/GRASSDATA/ output=testvectmap min_area=0.0001
snap=-1 
----
  
How many shapefiles did you have in the GRASSDATA directory?
What does testvectmap contain? You should make two separate GRASS vectors, one for the tracks and one for the contours. You can use the 'layer' parameter each time to specify each shapefile, like:
v.in.ogr dsn=/home/george/GRASSDATA/ layer=contours.shp output=contours

Display vector map: (no problems, map displayes correctly)
d.vect [EMAIL PROTECTED] color=0:0:0 lcolor=0:0:0
fcolor=170:170:170 display=shape type=point,line,boundary,area
icon=basic/circle size=5 layer=-1 lsize=8 xref=left yref=center llayer=1
----
  
At this point I'd check to make sure the elevation data came thru:
v.info -c     # shows the column headers, to make sure you have ELEVATION
v.db.select  # shows the actual ELEVATION values
Convert vector to raster and thin: (no problems reported)
v.to.rast [EMAIL PROTECTED] output=testrastmap use=attr
type=point,line,area layer=1 column=ELEVATION value=1 rows=100000 
r.thin [EMAIL PROTECTED] output=thinrastmap iterations=200
----
Display raster map (PROBLEM:only displays large, brightly coloured
rectangles, no contours
d.rast [EMAIL PROTECTED] -o
----
  
How did you set up the Location/Mapset ? You might have a problem with the resolution.
What do you get from:
r.info testrastmap
g.region -p


At this point I stopped as I got the impression something was already wrong
but could not work out what.
Also, should I not rasterize the track data as well?
Any help would be appreciated. If you require the source shapefiles I have
no problems sending them to you.

  
Let's keep stabbing at it from your end. That's always the best way to understand the methodology.
Micha Silver wrote:
  
  
Yes. 
I think you should be looking at converting the shapefile contour lines
to a raster....

v.in.org to import the contour lines and tracks into grass 
v.to.rast and r.thin to convert the contour lines to a raster map. 
r.surf.contour to create an elevation surface from the rasterized
contours 
r.profile to get the elevations along the tracks. 

Post back with specific questions if you hit a snag. 

Regards, 
Micha 

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