[postgis-users] TR: St_AsEwkt

Olivier Leprêtre o.lepretre at gmail.com
Thu Jul 6 03:31:34 PDT 2017




Yes, you're certainly right, there must be other way of doing that, it's an old bigger script which I was revisiting. I just extracted a small part of it. It uses pgplsql because the purpose is to create tables of results. Using st_AsEwkt was the only way I found to get geometry from a loop and pass it in another loop.






De : postgis-users [mailto:postgis-users-bounces at lists.osgeo.org] De la part de Tom van Tilburg
Envoyé : jeudi 6 juillet 2017 10:55
À : PostGIS Users Discussion
Objet : Re: [postgis-users] St_AsEwkt


Somehow I feel there is no need for plpgsql in what you are doing and that indeed the ST_AsEwkt is too much.

I can't wrap my head around what this script is exactly trying to do though. Can you elaborate a bit on your use-case? What is the original data and what would you like to know from it?






On Wed, Jul 5, 2017 at 7:54 PM, Olivier Leprêtre <o.lepretre at gmail.com> wrote:



I'm using pgplsql to calculate shortest distance between points. This works but I'm wondering if my code is optimized because I'm using many ST_AsEwkt.


sqls='SELECT id code,ST_AsEwkt(ST_StartPoint(the_geom)) as geom1,ST_AsEwkt(ST_EndPoint(the_geom)) as geom2 FROM ' || schem || '.trench';

FOR row IN 

            EXECUTE (sqls)



            sqls1='SELECT id code1,ST_Distance(ST_AsEwkt(the_geom),St_AsEwkt(''%2$s'')) FROM %1$s.nodes order by ST_Distance(ST_AsEwkt(the_geom),ST_AsEwkt(''%2$s'')) LIMIT 1';



            FOR row1 IN

                        EXECUTE (sqls1)



Would it be possible to have a smarter syntax with less ST_AsEwkt ?







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