[GRASSLIST:2330] Re: Removing a section of a raster map

Rich Shepard rshepard at appl-ecosys.com
Thu Aug 9 09:28:12 EDT 2001

On Thu, 9 Aug 2001, Michel Wurtz wrote:

> Try v.digit on a new (empty) vector file, with your raster map as background.
> You can maunally draw a rectangular area around your data, without the
> protusion.
> dont forget to give a label to your area (1 is good), run v.support and
> v.to.rast.
> You should now have a mask that you can use with r.mapcal: output = input * mask


  I believe that this is what I tried. With the raster map displayed in the
monitor, I invoked v.digit. Went through the questions on the screens and
told it to do only the border (not the internal "edges"). As soon as I
regained control, the raster map had been cleared from the monitor and a
thin, white vertical line near the center was present. The vertical line may
have been the right side of a rectangle because it looked like other lines
were along the top, left, and bottom of the monitor window.

  When the raster image displays in the monitor, it is centered
horizontally and has space on either side. Why it disappeared when I invoked
v.digit I cannot say. For that matter, as I was watching the window with the
v.digit setup I cannot even tell you just when the monitor changed.



Dr. Richard B. Shepard, President

                       Applied Ecosystem Services, Inc. (TM)
            2404 SW 22nd Street | Troutdale, OR 97060-1247 | U.S.A.
 + 1 503-667-4517 (voice) | + 1 503-667-8863 (fax) | rshepard at appl-ecosys.com
                 Making environmentally-responsible mining happen.

More information about the grass-user mailing list