[GRASS-dev] terminology issues in grass7

[Markus GRASS]

Paul Kelly wrote:
> On Fri, 12 Jun 2009, Hamish wrote:
>
>
>> as for vector layer renaming, I'd continue on about how an abstract idea
>> can be much better than an overly mechanical description if the analogy
>> is just right
>
> Perhaps a more abstract term that generalises the concepts of both
> layer and catset is needed here; unfortunately the more I think about
> it, the more "layer" seems to fit this need, so I'm not much help in
> this part of the discussion...
Adding my 2 cents (as a non-native speaker:-)). Vector layers are used
to work on a subset or selection of geometry objects in a given vector.
This subset may or may not be linked to an attribute table. This is
technically realised by assigning a combination of category value and
layer (field) number to a geometry object. All geometry objects that
have a category value specified for a given layer are available in that
layer, others not. Linking to an attribute table is usually done through
the key field cat. So far just to remind myself what that vector layer
does, and what it is good for.

Keyset and catset are more on the technical side as a description, but I
personally find these terms not intuitive. I know it's not a good idea
at this stage of the discussion to come up with yet another word to
replace layer, but how about subset? Because by choosing a vector
"layer" you effectively select a subset of geometry objects in the
vector map layer ;-), optionally linked to an attribute table specific
for this subset. You would then display or process everything in a
vector map or just a vector map subset (keeping in mind that a subset
may contain all geometry objects present in a vector). As with keyset or
catset, it is possible with some modules to make a custom selection
through the 'where 'option, creating a custom keyset/catset/subset, so
none of these words is completely unambiguous. Either a new word is
introduced (e.g. keyset/catset) that then needs to be explained to users
(not very user-friendly) or some word will surface in this discussion
that already has a general meaning close to what GRASS vector layers are
there for. Subset is hopefully a descriptive, not too technical term
that indicates by its name what it is.

Markus M