[GRASS-dev] How to check if a vector map is multi-layer?

[Markus Metz]

On Tue, Oct 28, 2014 at 4:49 PM, Markus Neteler <neteler at osgeo.org> wrote:
> On Tue, Oct 28, 2014 at 4:25 PM, Markus Metz
> <markus.metz.giswork at gmail.com> wrote:
>> On Tue, Oct 28, 2014 at 3:49 PM, Markus Neteler <neteler at osgeo.org> wrote:
>>> Hi,
>>>
>>> it would be nice to have in v.info or v.category the possibility to
>>> check if a vector map comes with multiple layers.
>>> I didn't figure out how to add that in these or one of these modules.
>>> Perhaps I am missing something.
>>
>> Does
>>
>> v.category option=layers
>>
>> not help?
>
> v.category k_buffer1000m option=layers
> 1
>
> Right that works but at this point I have to rephrase my question :-)
>
> We have the issue of overlapping polygons (v.buffer done on points)
> which are a separate issue in itself, hence the resulting print report
> for the categories is as such:
>
> 25/30/28/29/26/27/138/137/136/139/135/140
> 56/182
> 55/181/56/182
> 58/59/62/61/184/185/187/188/55/181/56/57/182/183
> 58/59/62/61/184/185/187/188/55/181/57/183
> 55/181/56/60/182/186
>
> That's a set of categories g.gui.rlisetup cannot handle.

So the question is how to handle multiple categories per feature and
layer instead of multiple layers per vector?

Would it be so difficult to enable g.gui.rlisetup to handle these cases?

> In order to
> avoid that it dies with ugly messages we want to catch such situations
> and exit with a proper error message...

Alternatively, g.gui.rlisetup and the r.li.* logic could be changed to
accept such situations.

Markus M