Removing unwanted nodes

[Susan Huse]

> I want to be able to define the vectors as areas.  I'm not sure how to do
> that if each of the areas is made up of multiple lines.  Also, I have
> nodes in my data that do not mark the intersection of two polygons.
> 
> for example
> 
>   N*********N**********N***********N
>   *  veg1   *       veg2           *
>   *         *                      *
>   N*********N****************N*****N
> 
> N=nodes
> 
> The nodes seem somewhat random.  
> 
> Thanks,
> 
> Melissa Cowoski
> Stanford University
> cowoski at pangea.stanford.edu
> 


Well, I don't know what more to tell you about the extraneous nodes except
taht they don't matter.  GRASS has no problem defining areas made of more
than one area edge.  

To define the areas, use v.digit.  The "lines" defining the area must be
area edges, not lines. As you come into v.digit, the default color for
area edges is grey, for lines is blue, for labeled lines magenta.

Be sure to run v.support before entering v.digit if you haven't already.

If they aren't area edges make them so.  (there are several ways to do
this, which I can tell you about if you need to).

Under the Label options in v.digit choose a - Label Areas.
Then it is a point and click process to label the areas.  If it beeps
and "cannot create area" then there is a topology problem.  You will
then need to check the nodes, etc.  

If you have more questions mail me directly sue at ced.berkeley.edu.

-sue