[postgis-devel] A letter to the Postgis Developers and Packagers

[Sandro Santilli]

On Fri, Feb 05, 2016 at 02:48:17PM +0100, Sebastiaan Couwenberg wrote:
> On 18-10-15 20:52, Andrea Peri wrote:
> > The new topological library of Tuscany Region will be deposited on a
> > distinct GIT repository, with an open license similar to that of
> > liblwgeom and of course we will be pleased and honored if in the future,
> > when it will be more robust and reliable, the Community of PostGIS
> > Developers and Packagers will decide to link it as a shared library for the
> > topological component functions.
> 
> Is there any news on the new topological library?

Current state is here:
https://gitlab.com/rttopo/rttopo

It is basically liblwgeom with symbols renamed to have an RT
prefix, the API reworked to be fully re-entrant and the SFCGAL
dependency removed.

> I'd like to drop the liblwgeom dependency from the spatialite Debian
> package, because it introduces a circular dependency that is
> complicating updates of GEOS, GDAL and related packages [0].

Wow, my head spins, the circularity is:

 liblwgeom -> sfcgal -> openscenegraph -> gdal -> spatialite ->
 liblwgeom

So rttopo should fix that, by cutting the "sfcgal" out.

> I'm seriously considering dropping the liblwgeom dependency from
> spatialite already to get rid of the circular dependency, but this will
> introduce an ABI break which I'd like to avoid. Resolving this situation
> will be painful either way, so we might as well get it over with now.

I feel your pain. Wouldn't it be wonderful if GDAL could use
runtime plugins for drivers ?

> If the new topological library will be available soon, and spatialite is
> updated to use it, the reduced functionality in spatialite will be a
> short lived issue. If not, we'll just have to live with the reduced
> functionality.

The first release should be available before the end of 2016, but
I dont' really have a date. It's mostly up to Alessandro Furieri
to do the spatialite side of it.

--strk;