[Qgis-developer] Get rid of Shapefiles ! Go GeoJSON !

haubourg regis.haubourg at eau-adour-garonne.fr
Mon Nov 26 13:19:33 PST 2012

Sandro Santilli-2 wrote
> I'm for abstraction too. It's pretty annoying to get prompted for
> a shapefile filename everytime you ask qgis to make an operation.
> It'd be much better to keep the layers in memory and ask the user
> for the format on close (want to save ? which format ?).
> Spatialite would make a good default.
> --strk;

Mmm it reminds me of an old discussion about memory layers and how to save
them along the project. three options where discussed:

1. first method implemented in Memory Layers Saver plugin: gml+xsd. verbose,
two files, and we encountered changes in GDAL behaviour about FID field (not
exposed and then exposed to conform to GML). This change broke all tools
that dealed with new labeling, which stores parameters based on field id's
and not their name (bad.. like Mapinfo, we should change that)

2. use a spatialite file along the qgs file storing all memory layers, or
even, a container (zip or spatialite) containing project and data. I must
say this is the good theorical target, but spatialite is moving fast..
Dealing with data type conversions, library version adds incompatibility
hazards, compared to an old and very stable format

3. use Qt serializing capacities with QDataStream. That's what is done in
Chris Crook new Memory Layer Saver. 

After some months after thoses discussions, this came up to me:
- QGIS 1.8 standalone is pretty broken with spatialite versions.. not yet
rock stable then.
- shp is not performing well when stored on a network.. rock stable but not
yet OK for most users. Limitations on character size is annoying and the
origin of many bugs
- shp is very loose on data types (text, integer, numeric + precision). This
is good for newbies, bad for advanced users . In the opposite spatialite is
more restrictive, so it can be more difficult to use for newcomers. 

we have some work remaining to consolidate both shp and sqlite. Maybe we
should concentrate our efforts on the existing, thant on new things a bit.
I'm trying to fund someone to work on shp issues, and 
 I vote for sqlite as preferd format. Supporting correctly GeoJSON correctly
with all tools and alike)  will take some time(tools to handle structure,
performances, size for big datasets). Last thing... spatialite can produce
geojson very simply, while the opposite is not true. I always prefer more
versatile formats.


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