Modifying layers / in-memory layers

[Bernhard Herzog]

Bernhard Reiter <bernhard at intevation.de> writes:

>> There is an
>> implementation of an in-memory table, MemoryTable, but it doesn't seem
>> to be used anywhere, is this so?  
>
> I think the tests might use it.

It's also used in GREAT-ER:
http://great-er.intevation.org/

>>  - What do you think of the in-memory stores idea?  Is there an
>> implementation I haven't seen?  Is there a reason not to do this all
>> together?  Is a postgis store a better idea?
>
> I believe in-memory is fine for a start. Most changes will be small.
> There should be a "commit" function to make the change permanent
> and possibly a "save-as" function to save to as many targets as we can which 
> would include postfix/gis as well, if possible.
[...]
>>  - Has anybody tried SpatiaLite? http://www.gaia-gis.it/spatialite/ I
>> haven't, but it might come in handy as a middle point between keeping
>> layers in memory and needing to set up a postgis database.
>
> I have not tried it, my strong guess is that it was not available when Thuban 
> was designed. We were quite early in adoption sqlite.
> Could be a good idea for transient data, as it is used for tables
> already.

If we're talking about serious additions to Thuban's data model, it
might be good to move to an integrated geometry + attribute data model
first.  That's basically what PostGISShapeStore already is.  See also
the comment in Thuban/Model/data.py.

   Bernhard

-- 
Bernhard Herzog                              Intevation GmbH, Osnabrück
Amtsgericht Osnabrück, HR B 18998             http://www.intevation.de/
Geschäftsführer: Frank Koormann, Bernhard Reiter, Dr. Jan-Oliver Wagner