[work] Re: [Qgis-user] No reference or details aboutthe "topological editiing" option in the documentation

[Andreas Neumann]

> A lot of us never understood, still don't, how ESRI could have ever

* probably some people don't care about data quality ...
* it is quicker to setup and maintain without topology
* the topology model in old ArcInfo also could get corrupted and often
required manual building/cleaning of the topology.

But I agree - there are also many disadvantages if correct topology is not
enforced.

> dropped topology in the first place. It's caused no end of headaches,
> and still is. The new approach has a lot more potential, encompassing
> a wider variety of rules and greater number of layers, but is harder
> to utilize because you need to set it up ahead of time and it is
> optional. With coverages you had no choice, topology is baked into the
> file format.

the new topology rules in ArcGIS go beyond to what was possible in old
ArcInfo - but in my experience it is sometimes unstable. I often got
crashes when I used the topology rules in earlier builds (tried about 2
years ago when I still had access to ESRI software)

> I'm pleasantly surprised and encouraged to see topology has been
> thought about and incorporated into qgis 1.0. :)

yes - but to be fair - it is not nearly as complete and powerful as the
topology rules in ArcGIS. What Marco implemented was more an editing
help/support than a topology rule that enforces correct topology. But is
great to have this support at all!

Andreas

-- 
Andreas Neumann
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