Definición
ST_Aggr_ConvexHull crea una geometría única que es una envoltura convexa de una geometría que resultó de una unión de todas las geometrías de entrada. En efecto, ST_Aggr_ConvexHull es equivalente a ST_ConvexHull (ST_Aggr_Union (geometrías)).
Sintaxis
Oracle
sde.st_aggr_convexhull (geometry sde.st_geometry)
SQLite
st_aggr_convexhull (geometry st_geometry)
Tipo de devolución
Oracle
ST_Geometry
SQLite
Geometryblob
Ejemplo
El ejemplo crea una tabla service_territories y ejecuta una declaración SELECT que agrega todas las geometrías, generando así una geometría única que representa la envoltura convexa de la combinación de todas las formas.
Oracle
CREATE TABLE service_territories
(ID integer not null, UNITS number, SHAPE sde.st_geometry);
INSERT INTO service_territories (id, units, shape) VALUES (
1,
1250,
sde.st_polygon ('polygon ((20 30, 30 30, 30 40, 20 40, 20 30))', 4326)
);
INSERT INTO service_territories (id, units, shape) VALUES (
2,
875,
sde.st_polygon ('polygon ((30 30, 30 50, 50 50, 50 30, 30 30))', 4326)
);
INSERT INTO service_territories (id, units, shape) VALUES (
3,
1700,
sde.st_polygon ('polygon ((40 40, 40 60, 60 60, 60 40, 40 40))', 4326)
);
SELECT sde.st_astext(sde.st_aggr_convexhull(shape)) CONVEX_HULL
FROM service_territories
WHERE units >= 1000;
CONVEX_HULL
POLYGON (( 20.00000000 40.00000000, 20.00000000 30.00000000, 30.00000000 30.00000000,
60.00000000 40.00000000, 60.00000000 60.00000000, 40.00000000 60.00000000, 20.00000000 40.00000000))
SQLite
CREATE TABLE service_territories (
ID integer primary key autoincrement not null,
UNITS numeric
);
SELECT AddGeometryColumn(
NULL,
'service_territories',
'shape',
4326,
'polygon',
'xy',
'null'
);
INSERT INTO service_territories (units, shape) VALUES (
1250,
st_polygon ('polygon ((20 30, 30 30, 30 40, 20 40, 20 30))', 4326)
);
INSERT INTO service_territories (units, shape) VALUES (
875,
st_polygon ('polygon ((30 30, 30 50, 50 50, 50 30, 30 30))', 4326)
);
INSERT INTO service_territories (units, shape) VALUES (
1700,
st_polygon ('polygon ((40 40, 40 60, 60 60, 60 40, 40 40))', 4326)
);
SELECT st_astext(st_aggr_convexhull(shape)) AS "CONVEX HULL"
FROM service_territories
WHERE units >= 1000;
CONVEX HULL
POLYGON (( 20.00000000 40.00000000, 20.00000000 30.00000000, 30.00000000 30.00000000,
60.00000000 40.00000000, 60.00000000 60.00000000, 40.00000000 60.00000000, 20.00000000 40.00000000))