Error using v.support

[Teresa Hansen]

Regarding the program for correcting polygon start nodes (fro Arc Ungenerate
data):   I would be greatly interested in getting a copy.


Teresa Hansen
Fort Lewis, Washington
teresa at lewis-deh2.army.mil



> From grass-lists-owner at moon.cecer.army.mil Thu Jun 29 01:24:03 1995
> Reply-To: R.Kunkel at kfa-juelich.de
> Subject: Re: Error using v.support
> 
> Steve,
> 
> I've got similar problems when importing ARC/INFO UNGENERATE vector data into
> GRASS. We found out that these errors may occur, when two neigboring polygons
> have identical starting points (first coordinate pair). Due to approximations
,
> which were made internally during building of the topology with v.support, it
> may happen that the generated node of one area is located within the other
> area. This leads to the error message you have mentioned. The problem is that
> you can't see this e.g. with v.digit, because it is done only internally.
> The problem can be solved by permutation of the starting point of either one 
of
> these polygons. Then, two different nodes will be generated and the area labe
ls
> will be assigned correctly. We have written a program, which performs such a
> permutation for all polygons given in ARC/INFO UNGENERATE format. Although th
e
> program works fine, at present, there are still some small bugs in our progra
m
> concerning the iteration process. Thus, it it necessary to call the program
> over and over, until all identical starting points are removed. Nevertheless,
> if you would like to get this program, please send me a mail. Right after
> fixing, I can put this program on moon additionally, if there's interest.
> 
> -- 
> Dr. Ralf Kunkel                               Tel: ++49-2461-613262
> Forschungszentrum Juelich GmbH                Fax: ++49-2461-612540
> Programmgruppe Systemforschung und    EMail: r.kunkel at kfa-juelich.de
> Technologische Entwicklung (STE)
> D-52425 Juelich, Germany
>