Novice: Contours from GIF
alcl01 at ipruniv.cce.unipr.it
Thu Sep 18 13:33:10 EDT 1997
At 08.06 18/09/97 +0000, you wrote:
>I've scanned most carefully a portion of a topographic map, ensuring
>that each pixel matches my resolution of five metres. So my GIF file is
>600 x 800 pixels, 3km by 4km.
>I've been able to import it using r.in.gif and then adjust it's location
>using r.support. Displaying it actually worked too, with d.rast.
>1) how do I make the display show only one portion of the area and
>magnify it to show the original level of detail? Or better?
>2) how do I now digitise the GIF to produce a vector map of the
I usually use:
r.thin (to thins lines)
r.line (to create a binary vector file)
v.support (to build the dig_plus file)
v.digit (to label contour lines).
If you have only contours on your GIF map, that's all you have to do, but
if you have other features you have to reclass (whit v.reclass) the
vector map saving only the labbelled contours
in a new file.
Hoping this helps you.
Dip. Scienze della Terra
Universita' di Parma
And a site map of some of the features?
>James Cameron (cameron at stl.dec.com)
>Digital Equipment Corporation (Australia) Pty. Ltd. A.C.N. 000 446 800
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