[GRASS-user] Vectorise a raster file

[Yves Jacolin]

Hi,
I created a raster with the visiblity function, and I wanted to vectorise it. 
I used v.to.vect but the result it is not good because there are holes in 
area that are fill by color (and have to be empty). I try to use mapcalc to 
remove all bad area, i try to remove it by db.execute but, if I list value, I 
have for all item value=1 but if I try to display the vector using this sql 
statement : value=1, the vector is correctly displaying ! If I export it in 
shp the vector is not correct !

To explain the problem, I try to calculate area where we can connect to a wifi 
ADSL connection. using aerial datas and SRTM90 usign r.los function.
If the elevation is upper than the aerial, signal is stoped ! So I have to get 
holes in area (My location is somewhere in the French alpes).

If you have an idea ...

Y. 
 
Yves Jacolin
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http://yjacolin.gloobe.org
http://softlibre.gloobe.org