ST_Boundary

Definición

ST_Boundary toma una geometría y devuelve su límite combinado como un objeto de geometría.

Sintaxis

Oracle y PostgreSQL

sde.st_boundary (geometry sde.st_geometry)

SQLite

st_boundary (geometry geometryblob)

Tipo de devolución

Oracle y PostgreSQL

ST_Geometry

SQLite

Geometryblob

Ejemplo

En este ejemplo, la tabla de límites se crea con dos columnas: tipo y geometría. Las declaraciones posteriores INSERT agregan un registro para cada una de las geometrías de subclase. La función ST_Boundary recupera el límite de cada subclase almacenada en la columna de geometría. Observe que la dimensión de la geometría resultante es siempre una menor que la geometría de entrada. Los puntos y los multipuntos siempre generan un límite que es una geometría vacía con dimensión –1. Las cadenas de texto de líneas y las multicadenas devuelven un límite de multipunto, dimensión 0. Un polígono o un multipolígono siempre devuelve un límite de multicadenas, dimensión 1.

Oracle

CREATE TABLE boundaries (
 geotype varchar(20),
 geometry sde.st_geometry
);

INSERT INTO BOUNDARIES VALUES (
 'Point',
 sde.st_pointfromtext ('point (10.02 20.01)', 4326)
);

INSERT INTO BOUNDARIES VALUES (
 'Linestring',
 sde.st_linefromtext ('linestring (10.02 20.01, 10.32 23.98, 11.92 25.64)', 4326)
);

INSERT INTO BOUNDARIES VALUES (
 'Polygon',
 sde.st_polyfromtext ('polygon ((10.02 20.01, 11.92 35.64, 25.02 34.15, 19.15 33.94, 10.02 20.01))', 4326)
);

INSERT INTO BOUNDARIES VALUES (
 'Multipoint',
 sde.st_mpointfromtext ('multipoint (10.02 20.01, 10.32 23.98, 11.92 25.64)', 4326)
);

INSERT INTO BOUNDARIES VALUES (
 'Multilinestring',
 sde.st_mlinefromtext ('multilinestring ((10.02 20.01, 10.32 23.98, 11.92 25.64), (9.55 23.75, 15.36 30.11))', 0)
);

INSERT INTO BOUNDARIES VALUES (
 'Multipolygon',
 sde.st_mpolyfromtext ('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)))', 4326)
);

SELECT type, sde.st_astext (sde.st_boundary (geometry)) "The boundary"
 FROM BOUNDARIES;

GEOTYPE            The boundary

Point              POINT EMPTY
Linestring         MULTIPOINT(10.02000000 20.01000000, 11.92000000 25.64000000)
Polygon            MULTILINESTRING ((10.02000000 20.01000000, 19.15000000 33.94000000,25.02000000 34.15000000, 11.92000000 35.64000000, 10.02000000 20.01000000))
Multipoint         POINT EMPTY
Multilinestring    MULTIPOINT (9.55000000 23.75000000, 10.02000000 20.01000000, 11.92000000 25.64000000, 15.36000000 30.11000000)
Multipolygon       MULTILINESTRING((51.71000000 21.73000000, 73.36000000 27.04000000, 71.52000000 32.87000000, 52.43000000 31.90000000, 51.71000000 21.73000000), (10.02000000 20.01000000, 19.15000000 33.94000000, 25.02000000 34.15000000, 11.92000000 35.64000000, 10.02000000 20.01000000))

PostgreSQL

CREATE TABLE boundaries (
 type varchar(20),
 geometry st_geometry
);

INSERT INTO boundaries VALUES (
 'Point',
 st_point ('point (10.02 20.01)', 4326)
);

INSERT INTO boundaries VALUES (
 'Linestring',
 st_linestring ('linestring (10.02 20.01, 10.32 23.98, 11.92 25.64)', 4326)
);

INSERT INTO boundaries VALUES (
 'Polygon',
 st_polygon ('polygon ((10.02 20.01, 11.92 35.64, 25.02 34.15, 19.15 33.94, 10.02 20.01))', 4326)
);

INSERT INTO boundaries VALUES (
'Multipoint',
st_multipoint ('multipoint (10.02 20.01, 10.32 23.98, 11.92 25.64)', 0)
);

INSERT INTO boundaries VALUES (
 'Multilinestring',
 st_multilinestring ('multilinestring ((10.02 20.01, 10.32 23.98, 11.92 25.64), (9.55 23.75, 15.36 30.11))', 4326)
);

INSERT INTO boundaries VALUES (
 'Multipolygon',
 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)))', 4326)
);

SELECT type, st_astext (st_boundary (geometry)) 
 AS "The boundary"
 FROM boundaries;

type              The boundary

Point              EMPTY
Linestring         MULTIPOINT(10.02000000 20.01000000, 11.92000000 25.64000000)
Polygon            LINESTRING ((10.02000000 20.01000000, 19.15000000 33.94000000,25.02000000 34.15000000, 11.92000000 35.64000000, 10.02000000
20.01000000))
Multipoint         EMPTY
Multilinestring    MULTIPOINT (9.55000000 23.75000000, 10.02000000 20.01000000, 11.92000000 25.64000000, 15.36000000 30.11000000)
Multipolygon       MULTILINESTRING((51.71000000 21.73000000, 73.36000000 27.04000000, 71.52000000 32.87000000, 52.43000000 31.90000000,
51.71000000 21.73000000), (10.02000000 20.01000000, 19.15000000 33.94000000, 25.02000000 34.15000000, 11.92000000 35.64000000, 
10.02000000 20.01000000))

SQLite

CREATE TABLE boundaries (
 type varchar(20)
);

SELECT AddGeometryColumn (
 NULL,
 'boundaries',
 'geometry',
 4326,
 'geometry',
 'xy',
 'null'
);

INSERT INTO boundaries VALUES (
 'Point',
 st_point ('point (10.02 20.01)', 4326)
);

INSERT INTO boundaries VALUES (
 'Linestring',
 st_linestring ('linestring (10.02 20.01, 10.32 23.98, 11.92 25.64)', 4326)
);

INSERT INTO boundaries VALUES (
 'Polygon',
 st_polygon ('polygon ((10.02 20.01, 11.92 35.64, 25.02 34.15, 19.15 33.94, 10.02 20.01))', 4326)
);

INSERT INTO boundaries VALUES (
 'Multipoint',
 st_multipoint ('multipoint (10.02 20.01, 10.32 23.98, 11.92 25.64)', 4326)
);

INSERT INTO boundaries VALUES (
 'Multilinestring',
 st_multilinestring ('multilinestring ((10.02 20.01, 10.32 23.98, 11.92 25.64), (9.55 23.75, 15.36 30.11))', 4326)
);

INSERT INTO boundaries VALUES (
 'Multipolygon',
 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)))', 4326)
);

SELECT type, st_astext (st_boundary (geometry)) 
 FROM boundaries;

Point              EMPTY
Linestring         MULTIPOINT(10.02000000 20.01000000, 11.92000000 25.64000000)
Polygon            LINESTRING ((10.02000000 20.01000000, 19.15000000 33.94000000,25.02000000 34.15000000, 11.92000000 35.64000000, 10.02000000
20.01000000))
Multipoint         EMPTY
Multilinestring    MULTIPOINT (9.55000000 23.75000000, 10.02000000 20.01000000, 11.92000000 25.64000000, 15.36000000 30.11000000)
Multipolygon       MULTILINESTRING((51.71000000 21.73000000, 73.36000000 27.04000000, 71.52000000 32.87000000, 52.43000000 31.90000000,
51.71000000 21.73000000), (10.02000000 20.01000000, 19.15000000 33.94000000, 25.02000000 34.15000000, 11.92000000 35.64000000, 
10.02000000 20.01000000))