[postgis-users] postgis topology question

[Fred Lehodey]

Hi,
you can do this using triggers.
Try something like that:



------1  Create a function that return a Trigger ::
CREATE OR REPLACE FUNCTION your_trigger() RETURNS TRIGGER as $$
BEGIN
    IF (TG_OP = 'UPDATE') THEN

        UPDATE your_edge_table SET the_geom =
st_makeline(NEW.the_geom,ST_Endpoint(the_geom))
        WHERE ST_DWithin(ST_Startpoint(the_geom),OLD.the_geom,0.0001);

        UPDATE your_edge_table SET the_geom =
st_makeline(ST_Startpoint(the_geom),NEW.the_geom)
        WHERE ST_DWithin(ST_Endpoint(the_geom),OLD.the_geom,0.0001);

            RETURN NEW;
        END IF;
        RETURN NULL;
END;

$$
language "plpgsql" volatile


----------------------------------------------------2  CREATE TRIGGER
CREATE TRIGGER zz_trig_luz
AFTER UPDATE ON your_node_table
    FOR EACH ROW EXECUTE PROCEDURE your_trigger();



Fred...







On Wed, Jan 27, 2010 at 7:07 AM, Absurd <programmerszp at gmail.com> wrote:

>
> Hi. I’m trying to use postgis topology. And I have a question.
> I have 3 nodes N1, N2, N3 and 2 edges E1 (with start_node = N1; end_node =
> N2) and E2 (with start_node = N2; end_node = N3). I want to move node N2.
> Do I have to select all edges, connected to node N2 (E1 and E2) and change
> their geometry too or there is such functionality in postgis topology?
>
> --
> View this message in context:
> http://old.nabble.com/postgis-topology-question-tp27334914p27334914.html
> Sent from the PostGIS - User mailing list archive at Nabble.com.
>
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