[GRASS-dev] GRASS vector and vector layer handling

Sören Gebbert soerengebbert at googlemail.com
Sun Jan 22 16:12:46 EST 2012

Dear all,
what do you think about a new approach of handling vector maps and
assigned database layer?

To access the vector/layer combination in a vector module, the user
must separately define the vector name and its layer number/name.
My suggestion is to combine the vector map and the layer identifier
using a colon for separation:

Vector map = roads
Layer = 1
Current mapset = user1

roads:1 at user1

Instead of:
v.db.select map=roads at user1 layer=1 ...
we can use
v.db.select map=roads:1 at user1 ...

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

This will of course make the handling of timestamped layer of a single
vector map much easier in the temporal GIS extension. :)

What do you think? How large would be the effort to implement this in grass7?

Best regards

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