[GRASSLIST:2336] Re: Removing a section of a raster map

Rich Shepard rshepard at appl-ecosys.com
Thu Aug 9 17:53:51 EDT 2001

On Wed, 8 Aug 2001, Hal Mueller wrote:

> hammer #2:  v.digit, using the original data as an underlying cell
> map, generate a polygon around the incorrect areas, build mask from
> that vector region

  I'm part way there, but missing a step and I don't know what it is.

  The key was using Customize | Background image in the v.digit menu to put
the raster, wart and all, on display. Then I zoomed in on the region,
digitized and quit. (Why it told me 2 more nodes were needed -- beyond the
five there -- I've no idea.) Ran v.support on the little rectangle. Looks
cute and is in the proper place (checked that already).

  Now comes the missing step.

  Using the vector file as input, I ran v.to.rast and assigned the output to
'mask'. OK so far. But, when I display 'mask', it covers the entire region
of the original map, not just the little digitized rectangle. Why?



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.

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