[postgis-users] [postgis-devel] linking 2 topogeometries of different nature

[Rémi Cura]

Hey all,

Hey Sandro.

The first beta version of the function is completed.
 ** GetRelatedTopogeom(source_topo topogeometry, target_topo_layer_id INT);
**
It returns set of topogeometry of the layer target_topo_layer_id that may
be affected by a change in topogeometry source_topo.

I consider it a mandatory function to be able to work consistently at the
topogeometry level, with multiple related topogeometry.

I'm entering testes, somebody has test db for postgis_topology?
I would need 2 topogeom layers of type puntal, lineal, areal ( 6 total).

I'm starting the test on my own data even if it is not ideal

Cheers,
Rémi-C


2013/10/23 Rémi Cura <remi.cura at gmail.com>

> I wrote down all the cases and here is the conclusion :
>
> *When looking for topogeom B related to topogeom A, we should get all
> elements of B which may be impacted by a change in A.*
> This definition of relation is much more clear and precise.
>
> So with this new definition,
>
> getting puntal/lineal/areal impacted by a change on a point is to take all
> node impacted (one) / all edge impacted by this node / all faces impacted
> by all edges impacted by the node.
>
> Same for a change in lineal or in areal.
>
> I'll re-code in this way.
>
> Cheers,
>
> Rémi-C
>
>
> 2013/10/23 Rémi Cura <remi.cura at gmail.com>
>
>> Hmm it can't work,
>>
>> please do not consider the previous message, i'm doing changes.
>>
>> Cheers,
>> Rémi-C
>>
>>
>> 2013/10/23 Rémi Cura <remi.cura at gmail.com>
>>
>>> Just to be sure could you validate please?
>>>
>>> The way I intend to find a source topogeom is related to target topogeom
>>> is like this (in sql pseudo code):
>>>
>>> element_id is supposed to be the element_id found in the relation table
>>> regarding *source* topogeom :
>>> Example : what are the (lineal) target topogeom related to the (puntal)
>>> source topogeom :
>>>
>>> `SELECT abs_next_left_edge UNION SELECT abs_next_right_edge
>>> WHERE element_id = start_node OR element_id = end_node`
>>>
>>>
>>> with the following
>>> target
>>>
>>> puntal : SELECT start_node UNION SELECT end_node
>>> lineal :  SELECT abs_next_left_edge UNION SELECT abs_next_right_edge
>>> areal : SELECT left_face UNION SELECT right_face
>>>
>>>
>>> source:
>>>
>>> puntal : WHERE element_id = start_node OR element_id = end_node
>>> lineal : WHERE element_id = abs_next_left_edge OR element_id =
>>> abs_next_right_edge
>>> areal : WHERE element_id = left_face OR element_id = right_face
>>>
>>>
>>>
>>> This may not be the optimal (we could use shortcut with edge_id), but it
>>> is symmetric in every way.
>>>
>>> Cheers,
>>> Rémi-C
>>>
>>>
>>> 2013/10/23 Rémi Cura <remi.cura at gmail.com>
>>>
>>>> Function getRelated is working for getting lineal related to a given
>>>> puntal topogeom,
>>>> now I'm trying to generalize so to be able to get any topogeom related
>>>> to any topogeom, whatever the feature_type.
>>>>
>>>> Cheers,
>>>>
>>>> Rémi
>>>>
>>>>
>>>> 2013/10/22 Rémi Cura <remi.cura at gmail.com>
>>>>
>>>>> OK,
>>>>>
>>>>> for my private function I don't expect several topogeom columns in one
>>>>> table.
>>>>> I can correct the getlayerid function but I don't think other people
>>>>> than me need it.
>>>>>
>>>>> For the GetRelated, I have a working query and I'm now trying to make
>>>>> it a plpgsql function
>>>>>
>>>>> Cheers,
>>>>> Rémi-C
>>>>>
>>>>>
>>>>> 2013/10/22 Sandro Santilli <strk at keybit.net>
>>>>>
>>>>>> On Tue, Oct 22, 2013 at 05:17:55PM +0200, Rémi Cura wrote:
>>>>>> > I'm sorry for being so disorganized,
>>>>>> > I lack experience with postgis_topology.
>>>>>> >
>>>>>> > It is only the 3d function I write for it.
>>>>>> >
>>>>>> > I was supposing you would need the layer_id in case there are
>>>>>> multiple
>>>>>> > topogeom columns in one table.
>>>>>> >
>>>>>> > Still I don't see a use case for having multiple topogeom columns
>>>>>> in the
>>>>>> > same table, even if I do use multiple geom columns for one table
>>>>>> sometimes.
>>>>>> >
>>>>>> > I totally agree with your others conclusions and proposed signature
>>>>>> > SET OF topogeometry GetRelatedLineal(
>>>>>> >            a_source_lineal_topogeom TOPOGEOMETRY,
>>>>>> >            a_target_puntal_topogeom_layer_id INT )
>>>>>>
>>>>>> Note that there's no problem with having multiple TopoGeometry
>>>>>> columns in
>>>>>> the same table, as long as you reference a each column (layer) by the
>>>>>> "topology_id"/"layer_id" pair (topology.layer primary key).
>>>>>>
>>>>>> > I don't like to put layer_id directly as input in function because
>>>>>> it is
>>>>>> > not a number user fixed.
>>>>>>
>>>>>> In that case you can specify (schema_name, table_name,
>>>>>> feature_column),
>>>>>> which _also_ identifies rows in topology.layer.
>>>>>>
>>>>>> > I think I can live with that as I wrote a function to get layer id
>>>>>> from the
>>>>>> > topogeom name :
>>>>>> > public.rc_getlayerid(layer_name text, layer_schema text DEFAULT
>>>>>> ''::text)
>>>>>>
>>>>>> Missing a column name here ?
>>>>>>
>>>>>> --strk;
>>>>>> _______________________________________________
>>>>>> postgis-devel mailing list
>>>>>> postgis-devel at lists.osgeo.org
>>>>>> http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-devel
>>>>>>
>>>>>
>>>>>
>>>>
>>>
>>
>
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