ST_IsClosed

Definition

ST_IsClosed takes an ST_LineString or ST_MultiLineString and returns 1 (Oracle and SQLite) or t (PostgreSQL) if it is closed; otherwise, it returns 0 (Oracle and SQLite) or f (PostgreSQL).

Syntax

Oracle and PostgreSQL

sde.st_isclosed (line1 sde.st_geometry)
sde.st_isclosed (multiline1 sde.st_geometry)

SQLite

st_isclosed (geometry1 geometryblob)

Return type

Boolean

Examples

Testing a linestring

The closed_linestring table is created with a single linestring column.

The INSERT statements insert two records into the closed_linestring table. The first record is not a closed linestring, while the second is.

The query returns the results of the ST_IsClosed function. The first row returns a 0 or f because the linestring is not closed, while the second row returns a 1 or t because the linestring is closed.

Oracle

CREATE TABLE closed_linestring (ln1 sde.st_geometry);
INSERT INTO CLOSED_LINESTRING VALUES (
 sde.st_linefromtext ('linestring (10.02 20.01, 10.32 23.98, 11.92 25.64)', 4326)
);

INSERT INTO CLOSED_LINESTRING VALUES (
 sde.st_linefromtext ('linestring (10.02 20.01, 11.92 35.64, 25.02 34.15, 19.15 33.94, 10.02 20.01)', 4326)
);
SELECT sde.st_isclosed (ln1) Is_it_closed
 FROM CLOSED_LINESTRING;

Is_it_closed

0
1

PostgreSQL

CREATE TABLE closed_linestring (ln1 sde.st_geometry);
INSERT INTO closed_linestring VALUES (
 sde.st_linestring ('linestring (10.02 20.01, 10.32 23.98, 11.92 25.64)', 4326)
);

INSERT INTO closed_linestring VALUES (
sde.st_linestring ('linestring (10.02 20.01, 11.92 35.64, 25.02 34.15, 19.15 33.94, 10.02 20.01)', 4326)
);
SELECT sde.st_isclosed (ln1) AS Is_it_closed
FROM closed_linestring;

is_it_closed

f
t

SQLite

CREATE TABLE closed_linestring (id integer);

SELECT AddGeometryColumn (
 NULL,
 'closed_linestring',
 'ln1',
 4326,
 'linestring',
 'xy',
 'null'
);
INSERT INTO closed_linestring VALUES (
 1,
 st_linefromtext ('linestring (10.02 20.01, 10.32 23.98, 11.92 25.64)', 4326)
);

INSERT INTO closed_linestring VALUES (
 2,
 st_linefromtext ('linestring (10.02 20.01, 11.92 35.64, 25.02 34.15, 19.15 33.94, 10.02 20.01)', 4326)
);
SELECT st_isclosed (ln1)
 AS "Is_it_closed"
 FROM closed_linestring;

Is_it_closed

0
1

Testing a multilinestring

The closed_mlinestring table is created with a single ST_MultiLineString column.

The INSERT statements insert an ST_MultiLineString record that is not closed and another that is.

The query lists the results of the ST_IsClosed function. The first row returns 0 or f because the multilinestring is not closed. The second row returns 1 or t because the multilinestring stored in the ln1 column is closed. A multilinestring is closed if all its linestring elements are closed.

Oracle

CREATE TABLE closed_mlinestring (mln1 sde.st_geometry);
INSERT INTO closed_mlinestring VALUES (
 sde.st_mlinefromtext ('multilinestring ((10.02 20.01, 10.32 23.98, 11.92 25.64), (9.55 23.75, 15.36 30.11))', 4326)
);

INSERT INTO closed_mlinestring VALUES (
 sde.st_mlinefromtext ('multilinestring ((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 sde.st_isclosed (mln1) Is_it_closed
 FROM CLOSED_MLINESTRING;

Is_it_closed

0
1

PostgreSQL

CREATE TABLE closed_mlinestring (mln1 sde.st_geometry);
INSERT INTO closed_mlinestring VALUES (
 sde.st_mlinefromtext ('multilinestring ((10.02 20.01, 10.32 23.98, 11.92 25.64), (9.55 23.75, 15.36 30.11))', 4326)
);

INSERT INTO closed_mlinestring VALUES (
 sde.st_mlinefromtext ('multilinestring ((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 st_isclosed (mln1)
 AS Is_it_closed
 FROM closed_mlinestring;

is_it_closed

f
t

SQLite

CREATE TABLE closed_mlinestring (mln1 geometryblob);

SELECT AddGeometryColumn (
 NULL,
 'closed_mlinestring',
 'mln1',
 4326,
 'multilinestring',
 'xy',
 'null'
);
INSERT INTO closed_mlinestring VALUES (
 st_mlinefromtext ('multilinestring ((10.02 20.01, 10.32 23.98, 11.92 25.64), (9.55 23.75, 15.36 30.11))', 4326)
);

INSERT INTO closed_mlinestring VALUES (
 st_mlinefromtext ('multilinestring ((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 sde.st_isclosed (mln1)
 AS "Is_it_closed"
 FROM CLOSED_MLINESTRING;

Is_it_closed

0
1

Related Topics

6/19/2015