map -> layer: no need for change; layer is less meaningful in this context
(my POV is not from the GUI layer-list perspective, so the metaphor makes
little sense)
layer -> catset: sorry, yuck.
(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]
map -> layer: no need for change; layer is less meaningful in this context
(my POV is not from the GUI layer-list perspective, so the metaphor makes
little sense)
I disagree, 'map' is completely confusing term (in my eyes) in this
context (my POV is "layer-based" GIS). Why GRASS should use different
term when other GIS packages and the most of GIS-related literature
use 'layer' in this context? I cannot see the point.
layer -> catset: sorry, yuck.
(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]
Catset seems to me as better choice, since it puts categories to the
set. (not strong opinion here)
(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:
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.
(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:
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).
(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:
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.
At least OGR calls them layers [e.g. 1, 2].
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.
Same for GRASS vector layers, as long as it's in the same projection and
topology does not interfere. Technically speaking, even two polygons in
the same shapefile have nothing in common because there is no topology
and they can not relate to the same entry in an attribute table.
They are just stored in the same place.
You could call that messy data management if data that have nothing in
common are stored in the same place, no offence;-) Just because it's
technically possible doesn't mean that it makes sense, and GRASS is
discouraging this although it is to a degree possible. Usually, when I
get a directory with shapefiles, they are indeed related to each other,
and if possible I import all of them into one vector as different layers.
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.
Same for GRASS vector layers, as long as it's in the same projection and topology does not interfere. Technically speaking, even two polygons in the same shapefile have nothing in common because there is no topology and they can not relate to the same entry in an attribute table.
They are just stored in the same place.
You could call that messy data management if data that have nothing in common are stored in the same place, no offence;-) Just because it's technically possible doesn't mean that it makes sense, and GRASS
is discouraging this although it is to a degree possible. Usually, when I get a directory with shapefiles, they are indeed related to each other, and if possible I import all of them into one vector as different layers.
Yeah well I guess I said all I wanted to. I bet everybody's going to be
glad if I don't interfere anymore :).
Yeah well I guess I said all I wanted to. I bet everybody's going to be
glad if I don't interfere anymore :).
Not as far as I am concerned. You emphasize the difference between
shapefiles and GRASS layers, I emphasize the similarity between GRASS
layers and shapefiles. I say we are both right. IOW, you look at
shapefiles -> GRASS layers in one GRASS vector which may not make sense,
I look at GRASS layers -> shapefiles, which is the only way that makes
sense. The discussion should be more about OGR layers than shapefiles as
layers, although shapefile is the most common imported and exported
format. The OGR layer concept is rather broad, and the question is, do
GRASS layers fit into that broad OGR layer concept or not.