[postgis-users] My crusade to get the real angle
nicky666 at gmail.com
Mon Jul 10 05:15:44 PDT 2006
> Hi list,
> I am still on my crusade to my real angle (not azimuth). Even with the
> mapserver doesen't helping me with labels I am sill trying to retrieve the
> real angle of a linestring.
> As you should know I have the azimuth of a set of linestrings and after a
> radians to degree conversion I noticed that the XY system is quite different
> from the Azimuth system and I need to do some conversions for each quadrant.
> So my question is: How do I apply a if statement on Postgis/Postgresql ? I
> know is is not a Postgis question but I think you could help me.
> I am trying to run this command line on psql:
> select angulo from mub;
> IF ANGLE >= 0 AND ANGLE <=90 THEN
> UPDATE TABLE MUB SET ANGLE = 90 – ANGLE
> END IF;
> But it does not work. Any help will be welcomed.
You may try to write a custom function (in Pl/PGSQL or another
language supported by postgis).
See the Postgresql documentation, "server programming -> Chapter 36.
PL/pgSQL - SQL Procedural Language"
You will be able to use control and loop structures.
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