[GRASSLIST:9096] Re: Raster-2-Vector Methodology Sugestions?

Luca Casagrande luca.casagrande at gmail.com
Wed Nov 16 03:44:38 EST 2005


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Hamish wrote:

>>I have a scanned color topo map an would like to filter out the brown
>>topo lines from blue rivers/grid lines and black writing, then
>>vectorize them to have just a contour map.
>>
>>So far I have not been very happy with the results. And I was
>>wondering if anyone has had any good experience and could share their
>>steps to get good results.
>>
>>I first ran i.cluster & i.maxlik, r.mapcalc to get the group that was
>>mainly the contours, r.thin , and then converted them to vector.
>
>
>
>what about loading into the GIMP or similar, select -> by color, select
>-> invert, edit-> cut, save. Then r.in.gdal, r.null, r.thin, r.contour
>or r.to.vect.
>
>
>
>Hamish
>
>
Hi Hamish,
have you got a sample of this operation? I'd like to put a walktrough
about this operation on my site...

Thx
Luca

- --
gtalk: luca.casagrande at gmail.com
skype : thedoktor78
msn: doktoreas at hush.com
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