[GRASSLIST:3804] Re: Vector Manipulation

[Christoph Simon]

On Fri, 31 May 2002 11:47:39 +0200
Radim Blazek <blazek at itc.it> wrote:

> On Thursday 30 May 2002 03:43 pm, Christoph Simon wrote:
> > > > And the other one is to select or
> > > > deselect certain lines in a resulting map C depending on their
> > > > presence in map A and/or B (with or without a snapdistance).
> > >
> > > I would use:
> > > v.to.rast  (A,B,C)
> > > r.report or r.mapcalc (or something)
> > > v.reclass or v.extract (based on results of r.* modules)
> >
> > Hm. Not sure to have understood this: You mean, I should use the
> > raster maps as a mask?
> 
> I'm not sure if I understand what you want. My idea was to do analysis
> in raster and then reclass vector according to results from raster
> analysis. 

I'm at the very beginning of the attempt to learn about GIS and Grass
teaching myself. I decided to start collecting data from the Internet,
join them and at least visualize some maps. I thought this might be a
first step. Now I have lots of data from many different places, mostly
incomplete and almost incompatibe. For instance, I've got one shape
file for some pieces of a political boundary with very nice
resolution, and another which is almost complete, including
subdivisions, but which is much coarser. So I try to cut out pieces
and join them together. At this point, I would like to keep the
original vertices. I didn't try it yet, but I guess, if I convert a
vector map to raster and back to vector, I might get more points with
less precision. Right?


-- 
Christoph Simon
ciccio at kiosknet.com.br
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