[GRASS-user] overlapping areas seem valid to v.build: why?

Markus Metz markus.metz.giswork at googlemail.com
Sat Dec 3 10:03:24 EST 2011


Benjamin Ducke wrote:
>
> Using data with unchecked topology is possible via "v.external".
> This module builds a pseudo topology that may be good enough in
> many cases. It works particularly well in GRASS 7.

Good point. In this case we could remove the -c flag for v.in.ogr in
trunk and always convert simple feature polygons to topological areas.
Supporting arguments would be that compared to GRASS 6, topology in
GRASS 7 is more robust, uses less resources, cleaning functions are
often faster, also use less resources, and vector topology including
cleaning functions is according to the bug tracker bug-free, AFAICT.

Markus M
>
>>
>> Thanks for all your hard work and commitment to this project,
>
> You are welcome. Thanks for your input.
>
> Best,
>
> Ben
>
>>
>> Roger
>> --
>>
>>
>>
>> > Markus M
>> >
>> > > Personally, I do not
>> > > think this "auto cleaning" should ever have been made the default
>> > operation
>> > > of the import tool.
>> > > --
>> > >
>> > >
>> > > On Wed, Nov 30, 2011 at 9:37 AM, Markus Metz
>> > > <markus.metz.giswork at googlemail.com> wrote:
>> > >>
>> > >> Moritz Lennert wrote:
>> > >> > On 30/11/11 14:38, Markus Metz wrote:
>> > >> >>
>> > >> >> It seems to me that the confusion arises because you made use of
>> > >> >> features that allow you to skip topological cleaning which is not the
>> > >> >> default and not recommended.
>> > >> >
>> > >> >
>> > >> > Maybe this calls for a v.check.topology module ? Or an option in
>> > v.build
>> > >> > or
>> > >> > v.clean which does that (i.e. just check, not clean) ?
>> > >>
>> > >> Good idea. I would opt for a new option/flag for v.build, which can
>> > >> already provide rather detailed diagnostics, e.g. dumping topology.
>> > >> Something like v.build -e for extended topology checks?
>> > >>
>> > >> Markus M
>> > >> _______________________________________________
>> > >> grass-user mailing list
>> > >> grass-user at lists.osgeo.org
>> > >> http://lists.osgeo.org/mailman/listinfo/grass-user
>> > >
>> > >
>> >
>>
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