Greetings,

[Raymond Venneker]

On Thu Apr 21 1994 Ted Cox <astec at acad2.alaska.edu > wrote:

> I hoping someone can help me with this. 
> 
> I'm having a few problems with v.support.  Occasionally, v.support will return
> errors when run after editing linework. Upon exiting v.digit, I run v.support to
> build new topology and get the following error messages:
> ==============================================
>   Building areas
>     Building islands
>     Attaching labels
> PNT_TO_AREA failed: (-22928.293381, 2328298.233617) (Category 2)
  ...

> PNT_TO_AREA failed: (200610.643394, 1072343.642725) (Category 213)
> =================================================================
> 
> I end up with a map with numerous open areas. Im running GRASS 4.1.2 on Linux
> 1.0 with 16 Megs RAM & 14 Megs of swap.  File size is around 10 megs. I've not 
> seen this behavior with GRASS4.0 before - does anyone have any ideas what's 
> going wrong?. I've also seen v.support fail on a regular basis after using 
> v.proj to move data between UTM and albers projections. Other than these
> instances it seems to work fine. 

I did have the open areas problem once after conversion from an alien
format to GRASS. v.digit couldn't find areas while labeling, but they
were closed so snapping didn't help. v.support failed. Files were 5-10 Mb.
What I did was removing the topology files (don't do this, save a backup)
found in the directory <database_path>/<location>/<mapset>/dig_plus.
Next, I ran v.support again and the problem was gone.

Hope this helps -Raymond