아래의 함수들은 PostGIS 사용자가 필요로 하는 함수들이며, 일반 사용자가 쓰지 않는 PostGIS 객체에 필요한 다른 지원 함수들도 있습니다.
PostGIS는 기존 명명 규칙에서 SQL-MM-중심 명명 규칙으로 전환하기 시작했습니다. 그 결과로, 여러분이 알고 있고 좋아하는 대부분의 함수 이름이 표준 Spatial Type (ST) 접두어를 사용한 이름으로 변경되었습니다. 갱신된 함수들이 이전 함수들과 같은 기능을 제공하며, 비록 이 문서에는 나열되어 있지는 않지만 이전 함수도 사용할 수 있습니다. 다음 버전 출시에는 이 문서에 없는 비 ST_ 함수들이 더 이상 사용되지 않을 것이며 제외될 예정이므로 이들 함수의 사용을 중단해 주십시오. |
이 섹션에서는 PostGIS에 의해 설치된 PostgreSQL의 데이터 유형을 나열합니다. 다음은 우리가 자신의 함수를 설계할 때 특히 중요한 이들의 캐스팅 동작을 설명합니다.
Each data type describes its type casting behavior. A type cast converts values of one data type into another type. PostgreSQL allows defining casting behavior for custom types, along with the functions used to convert type values. Casts can have automatic behavior, which allows automatic conversion of a function argument to a type supported by the function.
Some casts have explicit behavior, which means the cast must be specified using the syntax CAST(myval As sometype)
or myval::sometype
. Explicit casting avoids the issue of ambiguous casts, which can occur when using an overloaded function which does not support a given type. For example, a function may accept a box2d or a box3d, but not a geometry. Since geometry has an automatic cast to both box types, this produces an "ambiguous function" error. To prevent the error use an explicit cast to the desired box type.
All data types can be cast to text
, so this does not need to be specified explicitly.
These functions assist in defining tables containing geometry columns.
geometry_dump
rows for the components of a geometry.
geometry_dump
rows for the exterior and interior rings of a Polygon.
LINESTRING
의 시작점과 종단점이 일치하는 경우 TRUE
를 반환합니다. 다면체 표면이 닫혀 (부피를 가지고) 있는 경우 TRUE
를 반환합니다.
TRUE
를 반환합니다.
TRUE
를 반환합니다.
These functions create modified geometries by changing type, structure or vertices.
These functions test whether geometries are valid according to the OGC SFS standard. They also provide information about the nature and location of invalidity. There is also a function to create a valid geometry out of an invalid one.
valid_detail
row stating if a geometry is valid or if not a reason and a location.
These functions work with the Spatial Reference System of geometries as defined in the spatial_ref_sys
table.
These functions create geometry objects from various textual or binary formats.
LINESTRING
을 만듭니다.
These functions convert geometry objects into various textual or binary formats.
TRUE
를 반환합니다.
TRUE
if a geometry's (cached) 2D bounding box intersects a 2D float precision bounding box (BOX2DF).
TRUE
if a 2D float precision bounding box (BOX2DF) intersects a geometry's (cached) 2D bounding box.
TRUE
if two 2D float precision bounding boxes (BOX2DF) intersect each other.
TRUE
를 반환합니다.
TRUE
if a geometry's (cached) n-D bounding box intersects a n-D float precision bounding box (GIDX).
TRUE
if a n-D float precision bounding box (GIDX) intersects a geometry's (cached) n-D bounding box.
TRUE
if two n-D float precision bounding boxes (GIDX) intersect each other.
TRUE
를 반환합니다.
TRUE
를 반환합니다.
TRUE
를 반환합니다.
TRUE
를 반환합니다.
TRUE
를 반환합니다.
TRUE
if the coordinates and coordinate order geometry/geography A are the same as the coordinates and coordinate order of geometry/geography B.
TRUE
를 반환합니다.
TRUE
를 반환합니다.
TRUE
if a geometry's 2D bounding box is contained into a 2D float precision bounding box (BOX2DF).
TRUE
if a 2D float precision bounding box (BOX2DF) is contained into a geometry's 2D bounding box.
TRUE
if a 2D float precision bounding box (BOX2DF) is contained into another 2D float precision bounding box.
TRUE
를 반환합니다.
TRUE
를 반환합니다.
TRUE
를 반환합니다.
TRUE
if a geometry's 2D bonding box contains a 2D float precision bounding box (GIDX).
TRUE
if a 2D float precision bounding box (BOX2DF) contains a geometry's 2D bonding box.
TRUE
if a 2D float precision bounding box (BOX2DF) contains another 2D float precision bounding box (BOX2DF).
TRUE
를 반환합니다.
These functions determine spatial relationships between geometries.
These functions compute measurements of distance, area and angles. There are also functions to compute geometry values determined by measurements.
ST_Length
와 동일합니다.
ST_Perimeter
.
These functions compute results arising from the overlay of two geometries. These are also known as point-set theoretic boolean operations. Some related functions are also provided.
These functions compute geometric constructions, or alter geometry size or shape.
These functions operate on sets of polygonal geometry that form "implicit coverages". To form a valid coverage polygons must not overlap, and the vertices of adjacent edges must match exactly. Coverages are fast to process, and can be operated on with window functions, which retain the coverage topology inside the window partition while altering the edges.
These functions change the position and shape of geometries using affine transformations.
These functions implement clustering algorithms for sets of geometries.
These functions produce or operate on bounding boxes. They can also provide and accept geometry values, by using automatic or explicit casts.
See also Section 13.7, “PostGIS Box Functions”.
These functions support working with trajectories. A trajectory is a linear geometry with increasing measures (M value) on each coordinate. Spatio-temporal data can be modeled by using relative times (such as the epoch) as the measure values.
These functions report and upgrade PostGIS versions.
이 단원에서 사용자 지정 PostGIS GUC(Grand Unified Custom Variable)에 대해 설명합니다. 전체(global), 데이터베이스, 세션, 또는 상호처리(transaction) 단계에서 GUC를 설정할 수 있습니다. 전체 또는 데이터베이스 단계에서 설정하는 편이 가장 좋습니다.
These functions are utilities for troubleshooting and repairing geometry data. They are only needed if the geometry data is corrupted in some way, which should never happen under normal circumstances.