[QGIS-Developer] Support to loading GIS projects from an extended OWC geopackage in the QGIS core

Fri Dec 15 05:26:29 PST 2017

Hi all,

some years ago, we discussed of a new project file format able to store
data and other ressources has been discussed.

We finally had the opportunity to make one step forward when working on the
auxiliary data storage stuff.

What's the current status in QGIS 3:

- we now have an optional format ".qgz" that is a zipped file
- the auxiliary data storage is a sqlite database ".qgd" storing additional
informations joined to classical layers (for manual labeling purposes for
instance). It is NOT a spatialite database that could be the container for
spatial data
- when zip fil format is chosen, the qgd file is stored inside the qgz.

So, the path is opened to modify the offline editing tools or other
equivalent features to store their local datasource (either gpkg or sqlite)
inside the qgz too.

We also now have a container for storing SVG, color ramps, pictures or any
additionnal ressource that should be shipped within the project.

Now my opinion on the proposal about storing all inside a GPKG:

- I think we should first have a native "packaging" format using native qgs
file, to adress what offline editing, Qconsolidate, or QFieldSync use cases
requires.
- The "interoperability" use case should be adressed only as an option, not
a default solution, since SLD conversion (and things that don't stick to
standards) will alter the project.

I am in favor of discussing all that after QGIS3 is out so that we keep
focused on that,  and then discuss that at the Madeyra hackfest. I'd be
pleased to animate a workgroup to reach common agreement, guidelines, and
find a plan for that.

Best regards !
Régis

Le 15 déc. 2017 10:16, "Richard Duivenvoorde" <rdmailings at duif.net> a
écrit :

> On 14-12-17 13:59, Alessandro Pasotti wrote:
> > Hi Joana,
> >
> > I think this would be a great addition to QGIS.
> >
> > Big +1 from me, and thanks for the proposal.
> >
> >
> >
> > On Thu, Dec 14, 2017 at 1:49 PM, doublebyte <joana at doublebyte.net
> > <mailto:joana at doublebyte.net>> wrote:
> >
> >     Hello,
> >
> >     Maybe some of you are aware of the  "geopackage" plugin
> >     <https://eos.geocat.net/gitlab/joana.simoes/foss4g_gpkg/
> blob/master/foss4g_gpkg.pdf
> >     <https://eos.geocat.net/gitlab/joana.simoes/foss4g_gpkg/
> blob/master/foss4g_gpkg.pdf>>
> >     .The initial goal of this plugin was to enable users to save their
> QGIS
> >     projects, including style and associated resources
> >      in a extended geopackage -  the qgis geopackage extension
> >     <https://github.com/pka/qgpkg/blob/master/qgis_
> geopackage_extension.md
> >     <https://github.com/pka/qgpkg/blob/master/qgis_
> geopackage_extension.md>>
> >      -,
> >     and load it onto another QGIS installation; on this approach, the
> >     project is
> >     encoded as qgs, in a database table. Later the plugin was forked to
> >     support
> >     a different geopackage exension -  the owc geopackage extension
> >     <https://github.com/pka/qgpkg/blob/master/owc_
> geopackage_extension.md <https://github.com/pka/qgpkg/
> blob/master/owc_geopackage_extension.md>>
> >      - ,
> >     which is standards-based; in this  approach
> >     <https://www.geocat.net/announcing-the-extended-geopackage-
> qgis-plugin/
> >     <https://www.geocat.net/announcing-the-extended-geopackage-
> qgis-plugin/>>
> >     ,
> >     the style is encoded as OGC:SLD and the project as OGC:OWS context.
> >     The goal
> >     of this approach is to support the migration of GIS projects, as we
> can
> >     implement this extension in any desktop or server side GIS (e.g.:
> ArcGIS
> >     Desktop).
> >
> >     The fork was merged in August this year, and the latest release of
> the
> >     plugin <https://plugins.qgis.org/plugins/QgisGeopackage/
> >     <https://plugins.qgis.org/plugins/QgisGeopackage/>>   already
> contains
> >     both extensions, covering both use cases of porting QGIS projects and
> >     migrating GIS projects. Recently, it was added  support in the core
> >     to the
> >     "qgis geopackage extension"
> >     <https://github.com/qgis/QGIS/blob/master/src/
> providers/ogr/qgsogrprovider.cpp#L762
> >     <https://github.com/qgis/QGIS/blob/master/src/
> providers/ogr/qgsogrprovider.cpp#L762>>
> >     , in the qgsogrprovider class. This means that if a user loads a
> >     geopackage
> >     which was encoded using the "qgis geopackage extension", it will
> >     automatically load the QGIS project from it. We think that it makes
> >     sense to
> >     also add the  "ows geopackage extension" to the core; in that case,
> >     users
> >     could load projects exported from other GIS software seamlessly,
> without
> >     having to load the plugin. The mechanism would be very similar to
> >     what was
> >     already implemented for the  "qgis geopackage extension".
> >
> >     Before preparing any Pull Request, we would like to understand first
> >     what is
> >     the general feeling of the community about this feature; is this
> >     something
> >     which seems useful and interesting to add to the QGIS core? If yes,
> >     we would
> >     also appreciate any comments regarding any details the
> implementation.
> >
> >     Looking forward to hearing your feedback :-)
>
> Yes, please! I think there was an issue about not being able to load an
> extended gpkg:
>
> https://issues.qgis.org/issues/17698
>
> so it looks like fixing a bug
>
> :-)
>
> R
>
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