[QGIS-Developer] Discussing qgd files

[Régis Haubourg]

Hi,
just a quick followup about qgd file. Paul just merged that PR
https://github.com/qgis/QGIS/pull/6717 and qgd are now only created when
needed.
Thanks Andreas for raising the issue !


2018-03-07 18:45 GMT+01:00 Carlo A. Bertelli (Charta s.r.l.) <
carlo.bertelli at gmail.com>:

> A disruptive "moreover approach" suggests some reflection about the file
> <vs> database approach.
>
> I see several places where handling metadata in the database could provide
> a better but possibly conflicting solution.
> This happens for instance with styles stored on the database that may
> easily be overwritten by opening a modified project (if you work alone it's
> wonderful, but cooperating is a nightmare), but may happen also with any
> other "intelligent" provision that uses XML and/or persistent storage.
>
> I think this should not prevent a good solution about metadata. A map is
> not made of several layers overlaid with their styles only, it's something
> more and it's not completely satisfactory to reduce this to a project file
> that helps a single user to keep working on it or store the printing styles
> (sorry, I simplify too much, I know). Maybe QGD files are a starting point
> to design a better solution because we are embracing a three level storage
> system: files, light database (SQLite/Spatialite), DBMS (mainly
> PostgreSQL/PostGIS, but even others). This solution could lead us to a
> careful choice or to more flexibility (complexity?).
>
> Maybe this further flexibility is needed. I raise a very peculiar case: we
> work with historical maps and sometimes I georeference maps without being
> certain about my sources, sometimes the source itself is made of parts that
> ask two set of conflicting reference points for the same file. I'm forced
> to make a symlink on the filesystem to have the same file georeferenced in
> two ways. Why the different point sets cannot be stored on database? The
> reference points are points on earth and frequently I need to reuse them
> (what about adjacent tables? Maybe snapping on them could help), why not
> storing them in the database?
>
> QGIS Server is an amazing tool, but why using monolithic and completely
> proprietary XML file while several other applications could benefit from
> more generic metadata stored in the database? That is already done for
> styles which store SLD values besides the Qt ones, but it could be extended
> to other areas.
>
> It's reasonable to blame my "moreover approach", but take what you think
> QGIS could benefit of.
> c
>
> --
> --------------------------------------------------------------------------
> Carlo A. Bertelli
>    Charta servizi e sistemi per il territorio e la storia ambientale srl
>           Dipendenze del palazzo Doria,
>           vc. alla Chiesa della Maddalena 9/2 16124      Genova (Italy)
>           tel./fax +39(0)10 2475439  +39 0108566195  mobile:+39 393 1590711
>    e-mail: bertelli at chartasrl.eu      http://www.chartasrl.eu
> --------------------------------------------------------------------------
>
>
>
>
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