[GRASS-dev] GRASS vector and vector layer handling

Sören Gebbert soerengebbert at googlemail.com
Mon Jan 23 04:00:35 EST 2012


Hi Markus,

...
>>
>> Instead of:
>> v.db.select map=roads at user1 layer=1 ...
>> we can use
>> v.db.select map=roads:1 at user1 ...
>
> This would change the concept of fully qualified name, i.e. everything
> that uses the current concept of fully qualified name would need to be
> changed. This is a lot. The current concept applies to all elements,
> not only raster and vector maps, also e.g. region, group.
>>
>> In case no layer is provided, layer one is used as default ... . Hence
>> the definition of a layer is optional.
>> The explicit definition of a layer on module base will overwrite the
>> layer provided in the map identifier. Or maybe we can skip the layer
>> option?
>
> I think most modules that have a layer option already have a default
> answer, usually 1 or -1 for all.
>
>>
>> This will of course make the handling of timestamped layer of a single
>> vector map much easier in the temporal GIS extension. :)
>
> ...but changes the user interface for every module that works with
> vectors. Does it really matter how layers are defined through module
> options? Within the temporal GIS extension, the representation of
> vectors and their layers is surely independent of module options?
>
>>
>> What do you think? How large would be the effort to implement this in grass7?
>>
> Massive I guess. The vector lib and libgis would need modifications,
> and pretty much all modules working with vectors. And it breaks the
> universal concept of a fully qualified name.
>
> Not so convinced,

Ok. Was just an idea.

Best regards
Soeren

>
> Markus M
>
>> Best regards
>> Soeren
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