[GRASSLIST:1830] Re: Creating a DEM

[Markus Neteler]

On Fri, May 11, 2001 at 10:33:14AM +0200, michele.rocc at libero.it wrote:
> Hi,
> 
> I'm trying to create a DEM from a "scannerized" map, because of the 
> large amount of feature I thought to extract in some way the contour 
> lines using r.thin and r.line, then I heard that maybe there is som 
> problems in doing that

Hi,

maybe my last mail on r.line was confusing. In fact it does what's expected
(generates vector lines from raster lines even with diagonal lines. Hi Aldo
Clercini, maybe it's what you have been looking for).

> (something like r.surf.contour doesn't work fine  yet..).
It does, however it is still limited to CELL maps (no floating point dem's).
You can use it with fp maps as well, but will loose the precision.

> Well, is my idea possible to do? I know that any line will be 
> reproduced but I wanted to eliminate manually by v.digit the "not-
> contour" lines.
> Anyway, even it I decide to copy all contour lines point by point, is 
> there a working feature in GRASS to create the DEM?

You may use the v.surf.rst which runs very well and produces smooth DEMs.

Regards

 Markus