[Qgis-developer] QGIS -> Mapserver export

[Vincent Picavet]

Hi,
Following the discussion in the other thread («QGIS Globe and mapserver 
export»).

We at Oslandia started a very early proof of concept and work on
 QGIS->Mapserver interactions.

Warning : all this work is very alpha work, buggy, messy and not complete.

The first part is a plugin «à-la tilemill» to edit and watch live modifications 
of a mapfile, based on the sourcepole mapfile tools plugins, but greatly 
enhanced (with integrated editor).
It's there :
https://github.com/Oslandia/qgis-mapfile-tools

We work as well on QGIS->Mapfile export, as Hugo stated, based on Giuseppe's 
work, but without going through SLD :

https://github.com/Oslandia/rt_mapserver_exporter/tree/nosld
https://github.com/Oslandia/rt_mapserver_exporter/wiki/Todo

We chose the direct QGIS->Mapfile way because :
* SLD only covers a very small subset of QGIS/Mapserver symbology features
* SLD failed at being a reference format for styling (see the amount of 
various languages for that)
* Mapserver support for SLD is not really good

It would be great to have a common style interchange format, but I do not see 
that coming in the following years, and if it happens, it would probably be 
more a css-oriented format than SLD type.

The current "nosld" branch as Hugo said, focus on new symbology. Some 
incompatibilities exist between the two symbology systems, and they should be 
well documented (not that well covered as for now, see TODO).

There is a need for work on the mapserver side too, to facilitate writing this 
kind of converter, without having to leverage the whole mapserver stack. This 
would be a "libmapfile" library, independant from the renderer. Thomas has some 
ideas on that topic.

As for now, feel free to hack on our work and improve it. Maybe we should have 
a global "export" plugin with various export types, among them SLD, native 
mapserver, and the architecture to add more (Mapnik xml, carto, cartocss, 
cascadenik, google maps symbology...)

We do not really have time to work further on it by now, but we'll be happy to 
help and we intend to have some work done later in the year.

Vincent