[GRASSLIST:9206] Re: Raster DEM creation suggestions

Ian MacMillan ian_macmillan at umail.ucsb.edu
Wed Nov 23 13:07:39 EST 2005

Without seeing your data, as a general rule, use v.surf.rst to convert 
vector data (points and lines) to a raster surface.  Then you can use 
r.patch to patch all of your data into a single file.  You can use 
something like r.surf.idw or r.fillnulls to fill in spaces from there.  
When doing all of these steps make sure that your region resolution and 
bounding area is set appropriately.  This will affect both processing 
time and quality of data.  Depending on the size of your datasets, the 
interpolations may take a very long time (hours to days for large 
datasets).  Test your method first on a small piece of your data by 
reducing your region size (but keep the resolution the same as you want 
for your final product).

Hope this helps get you started.

On Nov 23, 2005, at 5:53 AM, Travis Kirstine GIS Tech wrote:

> Hi all,
> I'm fairly new to the grass world, and am hoping someone could provide
> assistance regarding DEM creation.  I have elevation data in several
> formats: orginal points and breaklines created during ortho 
> rectification in
> dgn format,ESRI TINS created from dgn file and 1m contours in shapefile
> format produced from the TINS. What would be the best method for 
> converting
> this data to grass dem rasters for use for further analysis considering
> accuracy, processing steps, edge matching etc...?  Any input would be 
> great
> Travis Kirstine
> First Base Solutions Limited
> 140 Renfrew Dr, Suite 100
> Markham ON
> L3R 6B3
> Phone 905.477.3600
> Fax 905.477.3882
> tkirstine at jdbarnes.com
What happens if a big asteroid hits Earth? Judging from realistic 
simulations involving a sledge hammer and a common laboratory frog, we 
can assume it will be pretty bad.
  - Dave Barry

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