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

[Rémi Cura]

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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