Martin, you are not being radical at all - this really needs
to be resolved and we have people with many different backgrounds here,
so it is not surprising that there are differences in how terminology
is understood.
So here are few of my comments:
Regarding the term map versus layer, I have ended up using
term "raster map layer" "vector map layer" in class and it works well
(I teach a very diverse group of graduate students - meteorology,
engineering, math, physics, geology, forestry, etc., but no geography
or geodesy - we don't have that at NCSU).
Given my original european, non-english background in cartography,
I tend to see map as a cartographic product, but after years of modeling and
working with non-cartographers, one has to admit that "map"
indeed is a more general term such as -
http://www.makelinux.net/kernel_map
http://www.smartmoney.com/map-of-the-market/
or human genome map http://www.ncbi.nlm.nih.gov/SCIENCE96/
As for GRASS tradition - the term for what we now call raster map and vector map
may have started as a map but it has grown into quite a mess
and you may remember the discussions
and effort to unify it in man pages and messages - it was called many things
(file, data, map, layer, etc.). Layer ended up being off-the-table because
it was already used for vector layer and at that time for some reason
nobody suggested to change it.
We had to use the term "map" in the grassbook to keep it in line with GRASS
documentation which I thought would be very confusing, but it ended up working OK
because there is much more focus on processing, analysis and modeling
than actually making maps as cartographic products.
If it is acceptable to have two word term I would vote for "map layer",
I found that people here better relate to raster map than to raster layer
and map layer (vector or raster) seems to be a good compromise and actually
more accurate than just map or just layer.
I tried to digg out some info about what our vector layer should be called
but I did not find anything useful, so please people who work with vector data
voice your opinion because you will have to work with whatever decision is made.
So far it seems we have Cat_set or Key_set?
Helena
On Jun 12, 2009, at 7:42 PM, Hamish wrote:
look, the "maps in MAPSETs" concept has been successfully used by GRASS
for more than 20 years, and indeed they are mentioned in the original
Fort Hood specification from 1983. I'm willing to tweak it a bit, but
not prepared to abandon that tradition.
As Michael mentioned, any difference in opinion probably arises from the
native English speakers vs. not. Whereas the non-native speakers take a
much more literal view of the word than the native speakers would. I
would expect native speakers to consider the word first and foremost an
abstract idea and not explicitly as cartography (and thus have no problem
adapting their brains to GRASS's usage, as it's a completely natural idea
for them). It's no reflection at all on the non-native speakers -- it's
not at all surprising: foreign languages are taught in school as words
next to a picture, simply as a noun. All nuance is lost and can take a
lifetime to grasp.
[I don't like using this sort of argument as it leaves little room for
rebuttal; you'll just have to take my word that I'm not using it as a
rhetorical trick..]
Indeed it's funny to think of feeding a literal paper map into a vector
module; up until now I'd never even considered that. I'll second
Michael's observation that none of our students here have ever expressed
any difficulty with the concept of a "map" as data. To me the abstract
meaning is the primary definition and the cartography one is just a
subset of that. If you've seen a lot of confusion about it over in your
neck of the woods* then it reinforces the idea that it is in fact a lost-
in-translation issue.
[*] I'm assuming that phrase doesn't translate well either 
no worries,
it doesn't make much sense here either
continuing,
Maps are inherently an abstract idea. Those lines on the paper represent
something more. Given that mindset abstracting it a little more is not
such a big jump. Maps can be verbal; think of "the roadmap to peace"; a
plan; probably most common as some lines drawn on the back of a napkin.
my proposal to resolve this is as follows-
modules & libraries: keep as "map" where it needs to be short
documentation and discussions: use "map layer" as a bridge
GUI: use "layer" to avoid namespace overlap with Map Display window.
As long as we talk about "map layers" enough people will easily figure
it out when one or the other of those words are missing, even if the
implied meaning is not natural to them.
vector layer would have to change to avoid overlap with GUI rendering
map layer. (IMHO cat|keyset is gobbledygook jargon, it may say what it
technically is, but it doesn't give any indication as to what it does)
For historical perspective I had a look through that 1987 video.
(the GRASS theme song is just awesome) At 1:20 into it William Shatner
discusses them as maps. At 2:06 he talks of them as layers. At 9:48 he
talks of them as "data layers", then goes back to talking about them as
maps again a few moments later. So free interchange between the terms is
nothing new.
I don't like "data layer", too generic. It does not say anything about
what it is. We're drowning in data these days & so we need to be as
descriptive as possible to keep it all straight. (no, "spatial data"
doesn't help narrow down the meaning much at all)
I've always found "data(base) tables" weird. I just think about chairs.
(difference being a table is not an abstract idea to begin with, it's
just a table)
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, but really I've got to get back to more important work
and I am afraid these discussions get us nowhere, slowly.
if it ain't broke!,
Hamish
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From this perspective, data layers seems sensible and I even talk about
geospatial data when I teach GIS. I also understand the cartographic
perspective that maps are the final, often paper, result of combining
multiple geospatial data layers. Nonetheless, most users will find it less
confusing if we just continue to call them maps--with the idea that we've
Which users? The users who I know are confused by "map" in the context
that is used in GRASS. I remember when I started to use GRASS as my
first GIS - I didn't understood why I should call raster file as
"map". Probably my feeling is too much cartographic one - map is some
kind of composition with given layout, decorations, text labels, etc.
When I display raster file/dataset/layer or whatever in GRASS, e.g.
'elevation' from spearfish location, it's not a map in my eyes. I
think that 'map' in this context is not right and whatever would be
better. Sorry probably to much radical this evening;-)
moved maps from paper to digital media. Note that this was the original
usage in one of the world's oldest GIS systems still in use (i.e., GRASS).
And looking at the 1980's video that someone rediscovered, the parallels
between paper maps and digital maps were made so that potential users could
better understand a GIS. From a personal perspective, I really don't mind
data layers at all. I just think that map is easer for most users to
understand even if it seems somewhat inaccurate from a more technical
perspective.
OK, anyway I still think that we should find more accurate term then
the current one. GRASS7 is good occasion (it takes time, and many
users will be confused for the short period).
Martin
--
Martin Landa <landa.martin gmail.com> * http://gama.fsv.cvut.cz/~landa
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