ST_Distance

Definition

ST_Distance gibt die Entfernung zwischen zwei Geometrien zurück. Die Entfernung wird von den nächsten Stützpunkten der beiden Geometrien gemessen.

Syntax

Oracle und PostgreSQL

sde.st_distance (geometry1 sde.st_geometry, geometry2 sde.st_geometry)

SQLite

st_distance (geometry1 geometryblob, geometry2 geometryblob)

st_distance (geometry1 geometryblob, geometry2 geometryblob, unit_name text)

Die folgenden Einheitennamen sind gültig:

Millimeter	Zoll	Yard	Link
Zentimeter	Inch_US	Yard_US	Link_US
Dezimeter	Fuß	Yard_Clarke	Link_Clarke
Meter	Foot_US	Yard_Sears	Link_Sears
Meter_German	Foot_Clarke	Yard_Sears_1922_Truncated	Link_Sears_1922_Truncated
Kilometer	Foot_Sears	Yard_Benoit_1895_A	Link_Benoit_1895_B
50_Kilometers	Foot_Sears_1922_Truncated	Yard_Indian	Kette
150_Kilometers	Foot_Benoit_1895_A	Yard_Indian_1937	Chain_US
Vara_US	Foot_1865	Yard_Indian_1962	Chain_Clarke
Smoot	Foot_Indian	Yard_Indian_1975	Chain_Sears
	Foot_Indian_1937	Fathom	Chain_Sears_1922_Truncated
	Foot_Indian_1962	Mile_US	Chain_Benoit_1895_A
	Foot_Indian_1975	Statute_Mile	Rod
	Foot_Gold_Coast	Nautical_Mile	Rod_US
	Foot_British_1936	Nautical_Mile_US
		Nautical_Mile_UK

Rückgabetyp

Doppelte Genauigkeit

Beispiel

Es werden zwei Tabellen, "study1" und "zones", erstellt und gefüllt. Die Funktion "ST_Distance" wird anschließend verwendet, um die Entfernung zwischen der Grenze jedes Teilgebiets und den Polygonen in der Flächentabelle "study1" zu ermitteln, die einen Nutzungscode von 400 aufweisen. Da sich drei Zonen auf dem Shape befinden, sollten drei Datensätze zurückgegeben werden.

In Oracle und PostgreSQL werden Einheiten in dem Projektionssystem definiert, das Sie verwenden. In diesen Beispielen sind es Dezimalgrad. In SQLite können Sie die Einheiten angeben. Da im Beispiel für SQLite Kilometer angegeben sind, wird die Entfernung in Kilometern zurückgegeben.

Oracle

--Create tables and insert values.
CREATE TABLE zones (
 sa_id integer,
 usecode integer,
 shape sde.st_geometry
);

CREATE TABLE study1 (
 code integer unique,
 shape sde.st_geometry
);

INSERT INTO zones (sa_id, usecode, shape) VALUES (
 1,
 400,
 sde.st_polygon ('polygon ((0 0, 0 10, 10 10, 10 0, 0 0))', 4326)
);

INSERT INTO zones (sa_id, usecode, shape) VALUES (
 2,
 400,
 sde.st_polygon ('polygon ((12 3, 12 6, 15 6, 15 3, 12 3))', 4326)
); 

INSERT INTO zones (sa_id, usecode, shape) VALUES (
 3,
 400,
 sde.st_polygon ('polygon ((20 0, 20 10, 30 10, 30 0, 20 0))', 4326)
);

INSERT INTO zones (sa_id, usecode, shape) VALUES (
 4,
 402,
 sde.st_polygon ('polygon ((40 0, 40 10, 50 10, 50 0, 40 0))', 4326)
);

INSERT INTO study1 (code, shape) VALUES (
 400,
 sde.st_polygon ('polygon ((-1 -1, -1 11, 11 11, 19 11, 31 11, 31 -1, 19 -1, 11 -1, -1 -1))', 4326)
);

INSERT INTO study1 (code, shape) VALUES (
 402,
 sde.st_polygon ('polygon ((39 -1, 39 11, 51 11, 51 -1, 39 -1))', 4326)
);

SELECT UNIQUE s.code, z.sa_id, sde.st_distance(z.shape, sde.st_boundary(s.shape)) DISTANCE
 FROM zones z, study1 s
 WHERE z.usecode = s.code AND s.code = 400
 ORDER BY DISTANCE;

code		sa_id      DISTANCE

400		       1					    1
400   			   3					    1
400    			  3					    4

PostgreSQL

--Create tables and insert values.
CREATE TABLE zones (
 sa_id integer,
 usecode integer,
 shape sde.st_geometry
);

CREATE TABLE study1 (
 code integer unique,
 shape sde.st_geometry
);

INSERT INTO zones (sa_id, usecode, shape) VALUES (
 1,
 400,
 sde.st_polygon ('polygon ((0 0, 0 10, 10 10, 10 0, 0 0))', 4326)
);

INSERT INTO zones (sa_id, usecode, shape) VALUES (
 2,
 400,
 sde.st_polygon ('polygon ((12 3, 12 6, 15 6, 15 3, 12 3))', 4326)
); 

INSERT INTO zones (sa_id, usecode, shape) VALUES (
 3,
 400,
 sde.st_polygon ('polygon ((20 0, 20 10, 30 10, 30 0, 20 0))', 4326)
);

INSERT INTO zones (sa_id, usecode, shape) VALUES (
 4,
 402,
 sde.st_polygon ('polygon ((40 0, 40 10, 50 10, 50 0, 40 0))', 4326)
);

INSERT INTO study1 (code, shape) VALUES (
 400,
 sde.st_polygon ('polygon ((-1 -1, -1 11, 11 11, 19 11, 31 11, 31 -1, 19 -1, 11 -1, -1 -1))', 4326)
);

INSERT INTO study1 (code, shape) VALUES (
 402,
 sde.st_polygon ('polygon ((39 -1, 39 11, 51 11, 51 -1, 39 -1))', 4326)
);

--
SELECT DISTINCT s.code, z.sa_id, sde.st_distance(z.shape, sde.st_boundary(s.shape))
 AS Distance
 FROM zones z, study1 s
 WHERE z.usecode = s.code AND s.code = 400
 ORDER BY Distance;

code	     sa_id		distance

400            1				  1
400            3			  	1
400     	      2			  	4

SQLite

--Create tables, add geometry columns, and insert values.
CREATE TABLE zones (
 sa_id integer primary key autoincrement not null,
 usecode integer
);

SELECT AddGeometryColumn (
 NULL,
 'zones',
 'shape',
 4326,
 'polygon',
 'xy',
 'null'
);

CREATE TABLE study1 (
 code integer unique
);

SELECT AddGeometryColumn (
 NULL,
 'study1',
 'shape',
 4326,
 'polygon',
 'xy',
 'null'
);

INSERT INTO zones (usecode, shape) VALUES (
 400,
 st_polygon ('polygon ((0 0, 0 10, 10 10, 10 0, 0 0))', 4326)
);

INSERT INTO zones (usecode, shape) VALUES (
 400,
 st_polygon ('polygon ((12 3, 12 6, 15 6, 15 3, 12 3))', 4326)
); 

INSERT INTO zones (usecode, shape) VALUES (
 400,
 st_polygon ('polygon ((20 0, 20 10, 30 10, 30 0, 20 0))', 4326)
);

INSERT INTO zones (usecode, shape) VALUES (
 402,
 st_polygon ('polygon ((40 0, 40 10, 50 10, 50 0, 40 0))', 4326)
);

INSERT INTO study1 (code, shape) VALUES (
 400,
 st_polygon ('polygon ((-1 -1, -1 11, 11 11, 19 11, 31 11, 31 -1, 19 -1, 11 -1, -1 -1))', 4326)
);

INSERT INTO study1 (code, shape) VALUES (
 402,
 st_polygon ('polygon ((39 -1, 39 11, 51 11, 51 -1, 39 -1))', 4326)
);

SELECT DISTINCT s.code, z.sa_id, st_distance(z.shape, st_boundary(s.shape), "kilometer") 
 AS "Distance(km)"
 FROM zones z, study1 s
 WHERE z.usecode = s.code AND s.code = 400
 ORDER BY "Distance(km)";

code  		sa_id      Distance(km)

400		       1					 109.63919620267
400   			   3					 109.63919620267
400    			  2					 442.30025845408