[GRASS-dev] terminology issues in grass7

[Maciej Sieczka]

Markus GRASS pisze:
> Hamish wrote:

>> (if it must be renamed, what's was wrong with going back to 
>> "field"?) [I remember Radim explained on-list why that was changed
>>  when it became "layer", ... need to dig out that thread]

> Here are two interesting threads [1,2], the same discussion about 
> field/layer between Trevor Wiens, Radim Blazek, Michael Barton, and 
> Moritz Lennert in March 2006:
> 
> [1] http://lists.osgeo.org/pipermail/grass-dev/2006-March/021646.html
>  and responses [2] 
> http://lists.osgeo.org/pipermail/grass-dev/2006-March/021659.html and
>  responses
> 
> Maybe layer is not that bad after all... GRASS can import several OGR
>  layers into one vector, each OGR layer will become a separate GRASS 
> vector layer. The main difference to e.g. several shapefiles imported
> as different layers into one GRASS vector is that GRASS builds and
> maintains topology for all geometry objects in all shapefiles
> combined.

> OGR layers and GRASS vector layers are not a 100% match, but IMHO 
> pretty close.

IMHO they are not close enough to call them the same name. GRASS
vector layers most of the time have common geometry or "subject", OGR
layers not necessarily. E.g. shapefiles in a directory don't need to
have anything in common. They are just stored in the same place. But
GRASS vector map layers are usually closely related to each other, in
some way (I guess that's what they are for - to represent extra data
which are so tightly related to the other data within the existing
vector map, that it's more convenient to store them together, than in
separate vector maps).

Maciek

-- 
Maciej Sieczka
http://www.sieczka.org