카테고리:: 지리 공간 함수

ST_MAKEPOLYGON , ST_POLYGON¶

Constructs a GEOGRAPHY or GEOGRAPHY object that represents a polygon without holes. The function uses the specified LineString as the outer loop.

참고 항목:: TO_GEOGRAPHY , TO_GEOMETRY

구문¶

ST_MAKEPOLYGON( <geography_or_geometry_expression> )

인자¶

geography_or_geometry_expression: A GEOGRAPHY or GEOMETRY object that represents a LineString in which the last point is the same as the first (i.e. a loop).

반환¶

The function returns a value of type GEOGRAPHY or GEOMETRY.

사용법 노트¶

The lines of the polygon must form a loop. Therefore, the last Point in the sequence of Points defining the LineString must be the same Point as the first Point in the sequence.
ST_POLYGON은 ST_MAKEPOLYGON의 별칭입니다.

For GEOMETRY objects, the returned GEOMETRY object has the same SRID as the input.

예¶

GEOGRAPHY Examples¶

이는 ST_MAKEPOLYGON 함수의 간단한 사용법을 보여줍니다. 아래의 일련의 점은 폭 1도, 높이 2도인 측지 직사각형 영역을 정의하며, 다각형의 왼쪽 하단 모서리는 적도(위도)와 그리니치(경도)에서 시작합니다. 시퀀스의 마지막 점은 루프를 완료하는 첫 번째 점과 동일합니다.

SELECT ST_MAKEPOLYGON(
   TO_GEOGRAPHY('LINESTRING(0.0 0.0, 1.0 0.0, 1.0 2.0, 0.0 2.0, 0.0 0.0)')
   ) AS polygon1;
+--------------------------------+
| POLYGON1                       |
|--------------------------------|
| POLYGON((0 0,1 0,1 2,0 2,0 0)) |
+--------------------------------+

GEOMETRY Examples¶

This shows a simple use of the ST_MAKEPOLYGON function.

SELECT ST_MAKEPOLYGON(
  TO_GEOMETRY('LINESTRING(0.0 0.0, 1.0 0.0, 1.0 2.0, 0.0 2.0, 0.0 0.0)')
  ) AS polygon;

+--------------------------------+
| POLYGON                        |
|--------------------------------|
| POLYGON((0 0,1 0,1 2,0 2,0 0)) |
+--------------------------------+