[gdal-dev] Binary Predicates in SQLite SQL dialect

[Jukka Rahkonen]

Even Rouault <even.rouault <at> spatialys.com> writes:

> 
> Le mardi 30 septembre 2014 20:20:14, Andre Vautour a écrit :

...

> > I would build SpatiaLite with GEOS support, but unfortunately its LGPL
> > licensing is too restrictive for our application. So, would it make
> > sense to change the logic in OGRSQLiteRegisterSQLFunctions to account
> > for the case of SpatiaLite being built without GEOS?
> 
> Andre,
> 
> That makes sense. I guess that can only be checked at runtime though,
probably 
> by issuing a ST_Intersects() and checking the error code.
> 
> I'd note that the spatial predicates in OGR geometry are also based on GEOS. 
> Except OGRGeometry::Intersects() that has a simplified implementation
based on 
> bounding box intersection when GEOS is not available.

Hi,

>From the end user's point of view this example feels unpleasant. If
"Intersects" gives different results with OGR and SQLite dialects because of
different implementations, a somewhat clever user can handle it now by
selecting the dialect. But if selecting SQLite dialect might still lead to
use of  OGRGeometry::Intersects() depending on how Spatialite has been built
I would say that an end user can't manage the situation.

How about renaming it into "OGR_Intersects" in such case?

-Jukka Rahkonen-