[GRASS-user] looking for a solution to a v.net error

[Markus Metz]

On Sun, Jan 20, 2013 at 1:33 PM, דור פרידמן <dof1985 at gmail.com> wrote:
> Hi all,
>
> I was using v.net (operation=connect) to create a network for a
> v.net.distance analysis. I'm using GRASS 6.4.2 using QGIS 1.8 plugin.
>
> My attempt to connect a polyline map with about 11000 categories to a points
> map with 25 has failed due to an error which described below.
>
>  My code was:
>>
>> v.net input=network points=cdw1c output=network_v2 operation=connect
>> threshold=4500
>
>
> My threshold is the maximum distance between a point category to the
> polyline map and was calculated by v.distance. I've also tried a smaller
> float to test it, namely threshold=100
> The error was:
>
> Windows alert claiming that v.net.exe has stopped working correctly... and
> the program was terminated.
> Additionally, I have received the following output in grass shell
>>
>> Assertion failed: !p->taken[i], file split_q.e, line 69
>
>
> An image using Prt Scr is attached.
>
> Can someone help me to figure out what am I doing wrong?

I think you did everything all right. The problem might rather be with
one of the vectors, containing corrupted coordinates. If the lines and
the points vector have been created with GRASS and never exported, it
is a bug in GRASS. If the lines and the points vector have been
imported into GRASS, there is a chance to figure out what went wrong:

both vectors must be in the same projection.
check the output of ogrinfo -so for both the lines and the points vector
check the output of v.info for both the imported lines and the
imported points vector

The extents of the imported vectors should not be larger than the
extents of the original vector. The extents of the imported vectors
can be smaller if you made a spatial selection during import.

In any case, run v.build on the two GRASS vectors and check for any warnings.

If possible, try GRASS 7, because GRASS 7 is more robust with regard
to vector processing.

If all that does not help, could you make the vectors available for testing?

Markus M