Novice: Contours from GIF

Radoslav Bonk bonk at
Thu Sep 18 03:25:32 EDT 1997

Hello James,

On Thu, 18 Sep 1997, James Cameron wrote:

> G'day,
> 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 and then adjust it's location
> using  Displaying it actually worked too, with d.rast.
> Questions:
> 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?
> -try to do this: run d.zoom and make a borders of your desired area /by
mouse/, then run d.erase.  Again run d.rast with your gif map , the
region you will see is that you done by d.zoom. Previuos region you can
call back by g.region /option 4 "set the current region by raster map"/  
-try to run d.display it's GUI in GRASS /most like the like d.zoom/
> 2)  how do I now digitise the GIF to produce a vector map of the
> contours?  And a site map of some of the features?
> -have no experiences
 Rado Bonk
> --
> James Cameron                                    (cameron at
> Digital Equipment Corporation (Australia) Pty. Ltd. A.C.N. 000 446 800

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