[GRASS-user] Topology built on demand

[Luiz Andrade]

Hi Stefan,
Thanks for your answer.
Let me clarify the terms I've used.
Our Spatial Data Structure is a set of 382 classes that are separated in 13
categories (e.g hydrography, vegetation and so on...).
Each category has a set of classes. In this email you can see a small
extract of the hydrography category.

In the case shown in the picture it is possible to see that objects
(features ) of the class called Recife (Reef in english) must be inside the
objects (features) of the class Massa_Dagua (Water polygons). The same
happens to the class called Ilha (Island in english). It's objects must be
inside the objects from the class Massa_Dagua.

This means that, those classes (reef, island, water polygons) must form one
topology. When I edit the reefs I must guarantee that no overlaps will be
formed between reefs and water polygons. This means that I need to move
together reefs and water polygons vertexes.

We have a QGIS plugin called DSGTools that creates a PostGIS databases
according to our structure, but PostGIS topology is still quite slow and I
can't deliver topology tools for my users using it.

This way, I want to append my PostGIS layers into one GRASS topology
(importing into GRASS) to be able to edit my vectors according to what is
determined in our Spatial Data Documentation (unfortunately it is
everything in Portuguese, but if you want, you can take a look on it here
http://www.geoportal.eb.mil.br/images/PDF/ET_EDGV_Vs_2_1_3.pdf).

So, this is my problem. I hope you can understand better now.

Thanks in advance!
Regards,
Luiz Claudio.





2016-09-22 16:52 GMT-03:00 Blumentrath, Stefan <Stefan.Blumentrath at nina.no>:

> Hi Luiz,
>
>
>
> It either very simple to answer your question or a quite difficult to
> answer based on the information your provided.
>
>
>
> The simple answer would be: Yes, of course this is possible in GRASS,
> thanks to it\s topological vector model! But that is probably not the
> answer you are after ;-)
>
>
>
> In order to give you suggestions on what to do however, we would need more
> information on what you actually want to achieve.
>
>
>
> Furthermore, I am afraid not everybody is familiar with the terms you use
> (at least I am not):
>
> What is you “spatial data structure”? Is that a set of thematic shape
> files? Several land cover types from one land cover dataset?
>
> What are sfs layers?
>
> What do you mean by “on demand” or “hierarchy”? Do you actually want to
> “snap” your hydrography data (and so on) to the vegetation data?
>
> Is there any (spatial) relation between the layers in your “spatial data
> structure” at the moment?
>
> Could you provide us with some examples?
>
>
>
> Cheers
>
> Stefan
>
>
>
> *From:* grass-user [mailto:grass-user-bounces at lists.osgeo.org] *On Behalf
> Of *Luiz Andrade
> *Sent:* 21. september 2016 14:44
> *To:* grass-user at lists.osgeo.org
> *Subject:* [GRASS-user] Topology built on demand
>
>
>
> How can I build a topology in grass with priority order on demand?
>
> I need to build a topology for my Spatial Data Structure. My structure has
> several sfs layers, but to validate my data I need to build a topology with
> several classes and according to a priority.
>
> This means that I want to insert my sfs layers into one topology structure
> in grass on demand.
>
> For instance, first I need to insert vegetation layers and later, insert
> hydrography layers and so on...
>
>
>
> Is it possible to make this on grass?
>
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