v.support problem

[Michel Wurtz - LTE]

Thomas Wilke wrote:
>
> after importing Arc-Ungenerate-Files as polygons into GRASS with
> v.in.arc I try
> to build the topology of the polygons with v.support. Most of the
> polygons are build correctly but for a small number I get a message like
> this:
> 
> PNT_TO_AREA failed: (3574062.500000, 5717337.500000) (Category 19000)
> 
> What is the reason for this message? And is there a solution for this
> problem?

That means that the polygon label point (whose coordinates are in
parenthesis) is not in a closed polygon. Some possible causes :
  - the point itself is misplaced in the original (A/I) data
  - some lines are missing, or not coded as area (look at the file
    with v.digit : color are not the same)
  - some polygon are not closed (node mismatch in grass) : look
    at the file with v.digit : a green dots is a node with only
    one line.
  - Maybe you have only inner lines and you need a neatline to
    close polygon at the border of the map...

Anyway, the best thing is to look at the file with v.digit with
the printed list of "PNT_TO_AREA failed" and look at the place
where label should be...

-- 
Michel Wurtz    ENGEES - Laboratoire Territoires & Environnement
                1, quai Koch - BP 1039, F-67070 STRASBOURG cedex
                Tel: +33 03.88.24.82.45  Fax: +33 03.88.37.04.97