[Qgis-developer] Bug with avoid intersection - willing to fund fix

[Giovanni Manghi]

On Thu, Nov 7, 2013 at 6:26 PM, George Silva <georger.silva at gmail.com> wrote:
> QGis does the explicit noding of the first adjancent feature, but the
> results are inconsistent.
>
> Sometimes it works, sometimes it doesnt. I've tried many things to see if I
> could find a reproducible series of steps, but without success.


I confirm. In one of the tickets I attached a screencast that shows
that is seems pretty random

https://www.dropbox.com/s/6elzwbwxcml1sck/postgis_editing_error.mp4


> Right now we are comparing the results ArcGIS is giving us against QGIS
> topology checker. It looks like QGIS topology checker is finding a lot more
> errors (I think QGIS is correct), but the main difference is visualization
> of the errors (which is another deal).


I also would like to stress that this is a really serious issue. In
QGIS we don't have (yet) tools to define the topology rules *before*
starting digitizing as other software does (see the other thread on
this matter). If the "avoid intersection" rule fails, we loose the
basically the only weapon we have and vectors need to be cleaned with
the "usual" tools (GRASS, postgis).