ST_Envelope
Définition
ST_Envelope renvoie l'emprise minimale d'un objet ST_Geometry sous forme de polygone.
Remarque :Cette fonction est conforme à la spécification en matière d'entités simples de l'OGC (Open Geospatial Consortium, Inc.) qui indique que l'objet ST_Envelope renvoie un polygone. Pour fonctionner avec des cas particuliers de géométries ponctuelles ou de lignes horizontales et verticales, la fonction ST_Envelope renvoie un polygone autour de ces formes qui se trouvent une unité au-dessus et au dessous des coordonnées x et y maximales et minimales.
Syntaxe
sde.st_envelope (g1 sde.st_geometry)
Type de retour
ST_Geometry
Exemple
La colonne geotype de la table envelope_test stocke le nom de la sous-classe de géométrie stockée dans la colonne g1 de type ST_Geometry.
CREATE TABLE envelope_test (geotype varchar(20), g1 sde.st_geometry);
Les instructions INSERT ci-dessous insèrent les différentes sous-classes de géométrie dans la table envelope_test.
Oracle
INSERT INTO ENVELOPE_TEST VALUES (
'Point',
sde.st_geometry ('point (10.02 20.01)', 0)
);
INSERT INTO ENVELOPE_TEST VALUES (
'Linestring',
sde.st_geometry ('linestring (10.01 20.01, 10.01 30.01, 10.01 40.01)', 0)
);
INSERT INTO ENVELOPE_TEST VALUES (
'Linestring',
sde.st_geometry ('linestring (10.02 20.01, 10.32 23.98, 11.92 25.64)', 0)
);
INSERT INTO ENVELOPE_TEST VALUES (
'Polygon',
sde.st_geometry ('polygon ((10.02 20.01, 11.92 35.64, 25.02 34.15, 19.15 33.94, 10.02 20.01))', 0)
);
INSERT INTO ENVELOPE_TEST VALUES (
'Multipoint',
sde.st_geometry ('multipoint (10.02 20.01, 10.32 23.98, 11.92 25.64)', 0)
);
INSERT INTO ENVELOPE_TEST VALUES (
'Multilinestring',
sde.st_geometry ('multilinestring ((10.01 20.01, 20.01 20.01, 30.01 20.01), (30.01 20.01, 40.01 20.01, 50.01 20.01))', 0)
);
INSERT INTO ENVELOPE_TEST VALUES (
'Multilinestring',
sde.st_geometry ('multilinestring ((10.02 20.01, 10.32 23.98, 11.92 25.64), (9.55 23.75, 15.36 30.11))', 0)
);
INSERT INTO ENVELOPE_TEST VALUES (
'Multipolygon',
sde.st_geometry ('multipolygon (((10.02 20.01, 11.92 35.64, 25.02 34.15,
19.15 33.94, 10.02 20.01), (51.71 21.73, 73.36 27.04, 71.52 32.87,
52.43 31.90, 51.71 21.73)))', 0)
);
PostgreSQL
INSERT INTO envelope_test VALUES (
'Point',
sde.st_point ('point (10.02 20.01)', 0)
);
INSERT INTO envelope_test VALUES (
'Linestring',
sde.st_linestring ('linestring (10.01 20.01, 10.01 30.01, 10.01 40.01)', 0)
);
INSERT INTO envelope_test VALUES (
'Linestring',
sde.st_linestring ('linestring (10.02 20.01, 10.32 23.98, 11.92 25.64)', 0)
);
INSERT INTO envelope_test VALUES (
'Polygon',
sde.st_polygon ('polygon ((10.02 20.01, 11.92 35.64, 25.02 34.15, 19.15 33.94, 10.02 20.01))', 0)
);
INSERT INTO envelope_test VALUES (
'Multipoint',
sde.st_multipoint ('multipoint (10.02 20.01, 10.32 23.98, 11.92 25.64)', 0)
);
INSERT INTO envelope_test VALUES (
'Multilinestring',
sde.st_multilinestring ('multilinestring ((10.01 20.01, 20.01 20.01, 30.01 20.01), (30.01 20.01, 40.01 20.01, 50.01 20.01))', 0)
);
INSERT INTO envelope_test VALUES (
'Multilinestring',
sde.st_multilinestring ('multilinestring ((10.02 20.01, 10.32 23.98, 11.92 25.64), (9.55 23.75, 15.36 30.11))', 0)
);
INSERT INTO envelope_test VALUES (
'Multipolygon',
sde.st_multipolygon ('multipolygon (((10.02 20.01, 11.92 35.64, 25.02 34.15,
19.15 33.94, 10.02 20.01), (51.71 21.73, 73.36 27.04, 71.52 32.87,
52.43 31.90, 51.71 21.73)))', 0)
);
Cette requête liste le nom de sous-classe et son enveloppe. La fonction ST_Envelope renvoie l'enveloppe entourant un objet point, linestring ou polygon.
Oracle
SELECT geotype, sde.st_astext (sde.st_envelope (g1)) Envelope FROM ENVELOPE_TEST; GEOTYPE Envelope Point POLYGON (( 9.02000000 19.01000000, 11.02000000 19.01000000, 11.02000000 21.01000000, 9.02000000 21.01000000, 9.02000000 19.01000000)) Linestring POLYGON (( 9.01000000 19.01000000, 11.01000000 19.01000000, 11.01000000 41.01000000, 9.01000000 41.01000000, 9.01000000 19.01000000)) Linestring POLYGON (( 10.02000000 20.01000000, 11.92000000 20.01000000, 11.92000000 25.64000000, 10.02000000 25.64000000, 10.02000000 20.01000000)) Polygon POLYGON (( 10.02000000 20.01000000, 25.02000000 20.01000000, 25.02000000 35.64000000, 10.02000000 35.64000000, 10.02000000 20.01000000)) Multipoint POLYGON (( 10.02000000 20.01000000, 11.92000000 20.01000000, 11.92000000 25.64000000, 10.02000000 25.64000000, 10.02000000 20.01000000)) Multilinestring POLYGON (( 9.01000000 19.01000000, 51.01000000 19.01000000, 51.01000000 21.01000000, 9.01000000 21.01000000, 9.01000000 19.01000000)) Multilinestring POLYGON (( 9.55000000 20.01000000, 15.36000000 20.01000000, 15.36000000 30.11000000, 9.55000000 30.11000000, 9.55000000 20.01000000)) Multipolygon POLYGON (( 10.02000000 20.01000000, 73.36000000 20.01000000, 73.36000000 35.64000000, 10.02000000 35.64000000, 10.02000000 20.01000000))
PostgreSQL
SELECT geotype, sde.st_astext (sde.st_envelope (g1)) AS Envelope FROM envelope_test; geotype envelope Point | POLYGON (( 9.02000000 19.01000000, 11.02000000 19.01000000, 11.02000000 21.01000000, 9.02000000 21.01000000, 9.02000000 19.01000000)) Linestring | POLYGON (( 9.01000000 19.01000000, 11.01000000 19.01000000, 11.01000000 41.01000000, 9.01000000 41.01000000, 9.01000000 19.01000000)) Linestring | POLYGON (( 10.02000000 20.01000000, 11.92000000 20.01000000, 11.92000000 25.64000000, 10.02000000 25.64000000, 10.02000000 20.01000000)) Polygon | POLYGON (( 10.02000000 20.01000000, 25.02000000 20.01000000, 25.02000000 35.64000000, 10.02000000 35.64000000, 10.02000000 20.01000000)) Multipoint | POLYGON (( 10.02000000 20.01000000, 11.92000000 20.01000000, 11.92000000 25.64000000, 10.02000000 25.64000000, 10.02000000 20.01000000)) Multilinestring | POLYGON (( 9.01000000 19.01000000, 51.01000000 19.01000000, 51.01000000 21.01000000, 9.01000000 21.01000000, 9.01000000 19.01000000)) Multilinestring | POLYGON (( 9.55000000 20.01000000, 15.36000000 20.01000000, 15.36000000 30.11000000, 9.55000000 30.11000000, 9.55000000 20.01000000)) Multipolygon | POLYGON (( 10.02000000 20.01000000, 73.36000000 20.01000000, 73.36000000 35.64000000, 10.02000000 35.64000000, 10.02000000 20.01000000))
7/10/2012