[GRASS-user] Strategy For DBMS Use

[Dylan Beaudette]

On Wednesday 18 November 2009, Rich Shepard wrote:
> On Wed, 18 Nov 2009, Pablo Carreira wrote:
> > I have very nice results with sqlite+GRASS.
>
> Pablo,
>
>    I've been using SQLite for several years; it's the back end to my
> approximate reasoning model for environmental impact assessments.
>
> > First, use an sqlite administrator software to make things easier.
>
>    I'm a CLI guy and prefer working by typing.
>
> > One database for each LOCATION, one table for each vector.
>
>    That's what I thought. Thanks for confirming.

I like this setup as well. However I have noticed one major shortcoming of 
this approach: when a long-running vector operation is using the SQLite 
database, no other processes can access vector attributes. I noticed this 
when performing a large v.patch job. No other vector modules that opened the 
attribute table would work, or would break with errors. Maybe there is 
something that can be done to solve this, however, it seems like the 
single-user nature of SQLite is to blame. One SQLite database per vector 
seems like a heavy-handed solution, but it would solve some of the 
problems--- while creating others...

Cheers,
Dylan


> > One way of working is that You can put rivers, highways, power lines,
> > etc. in the same "layer" and put a column in the table that describe what
> > kind of object it is. You can play with CAT number too, like rivers is
> > cat number x and highways is cat number y.
>
>    I'll need to think about this. Right now I have three locations, based
> on regional extent. Most layers are for the entire state, the DEM is for
> the northwest portion of the state and the soils are for a single county.
>
> > Try no to think as the obsolete shapefile style gis.
>
>    I've never used ARC/View. I did use ARC/Info on the Prime in the late
> 1980s, and a bit of ARC/Info-PC in the same period. Most of the mapping I
> did in the 1990s was with MapInfo running under VMware on a linux host. I
> last upgraded that in 1996. :-) Haven't done any GIS work for about 6
> years.
>
> > I am a agronomist engineer an I have made soil maps and soil use maps
> > with grass, just ask if you have more questions.
>
>    And I'm a stream ecologist/fluvial geomorphologist so I'm sure I'll have
> questions about antecedent soild moisture for the model I'm working toward
> building.
>
> Thanks,
>
> Rich
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-- 
Dylan Beaudette
Soil Resource Laboratory
http://casoilresource.lawr.ucdavis.edu/
University of California at Davis
530.754.7341