[Qgis-developer] QgsGeometry

[Marco Hugentobler]

On Wednesday 12 September 2007 10:39:59 Martin Dobias wrote:

> Yesterday I've took a look at GEOS library and found out that there is
> some kind of support for custom geometry classes - we could make our
> own CoordinateSequence class which would use QVector, our own
> CoordinateSequenceFactory for creation of these sequences and
> GeometryFactory from creation of our custom geometries. The only
> problem is that we still would need to use Coordinate class for the
> coordinates, but that's not that big problem. It comes with three
> member variables: x,y,z and some functions. I can imagine that we
> would derive e.g. QgsCoord class from it that will add some more
> functions for us if needed - in fact this class (QgsCoord) should
> replace QgsPoint, as QgsPoint should be in the new scheme derived from
> QgsGeometry.

> After all, we would get a common representation for QGIS where we
> could avoid any further conversions, I'm just a bit affraid if others
> would be okay with this as it's a rather radical change...

Yes, it will touch many existing lines in the whole codebase, including 
plugins. But in my opinion it's really worth doing it, as having a clean 
geometry represenation is very important for a GIS. 
It would therefore be good to have a wiki page and make a request for comments 
before starting to redesign the geometry.
 
As we make the redesign in a branch it will not disturb other development 
activities (at least in theory). So it should be easy to convince people.

Regards,
Marco


-- 
Dr. Marco Hugentobler
Institute of Cartography
ETH Zurich
Technical Advisor QGIS Project Steering Committee
marco.hugentobler at karto.baug.ethz.ch