[GRASS-user] new user question about mapsets, locations, and coordinate systems

[Hamish]

Hamish:
> a single "database" (where you keep all your grass data) can contain
> many locations.

Nikos: 
> I don't remember right now what I did some time ago and mixed my
> database(s) vs. LOCATION(s). Since then I decided to use separate
> database(s) files (sqlite.db's for example) to avoid mixing original and
> edited data.

ok there are two "databases" at work here. The first is the directory
which holds all your grass locations (aka $GISDBASE). It is just the
directory which is the "base" dir of all your "data".

the second is the DBMS used by v.db.* etc. it holds the attributes linked
from a vector map.

the default in grass 6 is DBF, and dbf tables are stored in $MAPSET/dbf/.
the default in grass 7 is SQLite, and (currently) all tables for that
mapset are stored in $MAPSET/sqlite.db.
[in both cases "or whatever you changed it to be"]

typically each MAPSET will have a default DBMS defined in the $MAPSET/VAR
file (db.connect), but individual maps can change what they use
(v.db.connect).

there is no LOCATION-wide DBMS setting, typically it is a per-MAPSET
decision.


> Any *best practice* suggestion?

I'm not really a heavy DB or vector user, so not from me,

there is an open debate if there should be (by default) a single
sqlite.db file per MAPSET or it should be split into one table (or collection of tables for a single map) per file, like dbf has.
That's just for the default way; you can customize it to be how you like...


Hamish