[postgis-users] Construcción de multipunto a partir de puntos en polígono

[Felix Kunde]

Hola Nestor,
 
I guess, what you're looking for is ST_Collect. ST_Multi is not an aggregate function. It's only useful if you need to bring all rows of a column into a multi representation.
 
Salduos
Felix
 

Gesendet: Mittwoch, 18. April 2018 um 16:18 Uhr
Von: "Néstor Ramires" <nramire1 at rosario.gov.ar>
An: "PostGIS Users Discussion" <postgis-users at lists.osgeo.org>
Betreff: [postgis-users] Construcción de multipunto a partir de puntos en polígono

Hola a todos
Tengo los siguientes datos:

CREATE TABLE arboles (
id SERIAL,
raiz geometry(Point, 22185)
);

INSERT INTO arboles (raiz) VALUES (ST_GeomFromText('POINT(1 1)',22185));
INSERT INTO arboles (raiz) VALUES (ST_GeomFromText('POINT(1 2)',22185));
INSERT INTO arboles (raiz) VALUES (ST_GeomFromText('POINT(5 2)',22185));
INSERT INTO arboles (raiz) VALUES (ST_GeomFromText('POINT(6 2)',22185));
INSERT INTO arboles (raiz) VALUES (ST_GeomFromText('POINT(5 3)',22185));
INSERT INTO arboles (raiz) VALUES (ST_GeomFromText('POINT(1 6)',22185));
INSERT INTO arboles (raiz) VALUES (ST_GeomFromText('POINT(3 6)',22185));


CREATE TABLE patrulla (
id SERIAL,
guardia int,
arboles geometry(MultiPoint, 22185),
region geometry(Polygon, 22185)
);

INSERT INTO patrulla (guardia, region) VALUES (1, ST_GeomFromText('POLYGON((0 0, 0 3, 3 3, 3 0, 0 0))',22185));
INSERT INTO patrulla (guardia, region) VALUES (2, ST_GeomFromText('POLYGON((4 1, 4 4, 8 4, 8 1, 4 1))',22185));
INSERT INTO patrulla (guardia, region) VALUES (3, ST_GeomFromText('POLYGON((2 8, 0 6, 2 4, 2 8))',22185));
INSERT INTO patrulla (guardia, region) VALUES (4, ST_GeomFromText('POLYGON((2 8, 5 6, 2 4, 2 8))',22185));

El objetivo es actualizar el campo arboles de la tabla patrulla, con una geometría multipunto que contenga todos los árboles de la región. Para ello utilizo la siguiente sentencia:

UPDATE patrulla mp 
SET arboles = ST_Multi(r.raiz)
FROM arboles r
WHERE ST_Contains(mp.region, r.raiz);

Que no estaría funcionando como yo esperaba, ya que en las regiones que tienen más de un árbol en su interior, sólo toma en cuenta el primero de ellos.
¿Alguno puede darme una idea de por dónde apuntar para buscar la solución?
 

 
--------------------------------------------------
 
Hello everyone
I have the following data:

CREATE TABLE arboles (
id SERIAL,
raiz geometry(Point, 22185)
);

INSERT INTO arboles (raiz) VALUES (ST_GeomFromText('POINT(1 1)',22185));
INSERT INTO arboles (raiz) VALUES (ST_GeomFromText('POINT(1 2)',22185));
INSERT INTO arboles (raiz) VALUES (ST_GeomFromText('POINT(5 2)',22185));
INSERT INTO arboles (raiz) VALUES (ST_GeomFromText('POINT(6 2)',22185));
INSERT INTO arboles (raiz) VALUES (ST_GeomFromText('POINT(5 3)',22185));
INSERT INTO arboles (raiz) VALUES (ST_GeomFromText('POINT(1 6)',22185));
INSERT INTO arboles (raiz) VALUES (ST_GeomFromText('POINT(3 6)',22185));


CREATE TABLE patrulla (
id SERIAL,
guardia int,
arboles geometry(MultiPoint, 22185),
region geometry(Polygon, 22185)
);

INSERT INTO patrulla (guardia, region) VALUES (1, ST_GeomFromText('POLYGON((0 0, 0 3, 3 3, 3 0, 0 0))',22185));
INSERT INTO patrulla (guardia, region) VALUES (2, ST_GeomFromText('POLYGON((4 1, 4 4, 8 4, 8 1, 4 1))',22185));
INSERT INTO patrulla (guardia, region) VALUES (3, ST_GeomFromText('POLYGON((2 8, 0 6, 2 4, 2 8))',22185));
INSERT INTO patrulla (guardia, region) VALUES (4, ST_GeomFromText('POLYGON((2 8, 5 6, 2 4, 2 8))',22185));
The objective is to update the Trees field of the patrol table, with a multipoint geometry that contains all the trees in the region. To do this I use the following sentence:

UPDATE patrulla mp 
SET arboles = ST_Multi(r.raiz)
FROM arboles r
WHERE ST_Contains(mp.region, r.raiz);
That would not be working as I expected, as in regions that have more than one tree inside, just take into account the first of them.
Can anyone give me an idea of where to aim to find the solution?_______________________________________________ postgis-users mailing list postgis-users at lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/postgis-users