line

infinite line on a plane

当前阅读 PG 18·选择有来源记录的版本

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Catalog name: pg_catalog.line
Type OID: 628
Type kind: Base type
Declared length: 24 bytes
Storage strategy: plain
Input function: line_in
Output function: line_out
Documented declaration: line
Storage Size: 24 bytes
Manual description: Infinite line
aliases: 未知
casts: 未知
coverage: source inventory; exact declared input types for operator classes
manual documentation: dedicated family chapter
manual path: datatype-geometric.html
operator classes: 未知
ranges: 未知
signature: line

版本定义 PG 18

8.8. Geometric Types

Geometric data types represent two-dimensional spatial objects. Table 8.20 shows the geometric types available in PostgreSQL.

Table 8.20. Geometric Types

Name	Storage Size	Description	Representation
`point`	16 bytes	Point on a plane	(x,y)
`line`	24 bytes	Infinite line	{A,B,C}
`lseg`	32 bytes	Finite line segment	[(x1,y1),(x2,y2)]
`box`	32 bytes	Rectangular box	(x1,y1),(x2,y2)
`path`	16+16n bytes	Closed path (similar to polygon)	((x1,y1),...)
`path`	16+16n bytes	Open path	[(x1,y1),...]
`polygon`	40+16n bytes	Polygon (similar to closed path)	((x1,y1),...)
`circle`	24 bytes	Circle	<(x,y),r> (center point and radius)

In all these types, the individual coordinates are stored as double precision (float8) numbers.

A rich set of functions and operators is available to perform various geometric operations such as scaling, translation, rotation, and determining intersections. They are explained in Section 9.11.

8.8.1. Points

Points are the fundamental two-dimensional building block for geometric types. Values of type point are specified using either of the following syntaxes:

( x , y )
  x , y

where x and y are the respective coordinates, as floating-point numbers.

Points are output using the first syntax.

8.8.2. Lines

Lines are represented by the linear equation Ax + By + C = 0, where A and B are not both zero. Values of type line are input and output in the following form:

{ A, B, C }

Alternatively, any of the following forms can be used for input:

[ ( x1 , y1 ) , ( x2 , y2 ) ]
( ( x1 , y1 ) , ( x2 , y2 ) )
  ( x1 , y1 ) , ( x2 , y2 )
    x1 , y1   ,   x2 , y2

where (x1,y1) and (x2,y2) are two different points on the line.

8.8.3. Line Segments

Line segments are represented by pairs of points that are the endpoints of the segment. Values of type lseg are specified using any of the following syntaxes:

[ ( x1 , y1 ) , ( x2 , y2 ) ]
( ( x1 , y1 ) , ( x2 , y2 ) )
  ( x1 , y1 ) , ( x2 , y2 )
    x1 , y1   ,   x2 , y2

where (x1,y1) and (x2,y2) are the end points of the line segment.

Line segments are output using the first syntax.

8.8.4. Boxes

Boxes are represented by pairs of points that are opposite corners of the box. Values of type box are specified using any of the following syntaxes:

( ( x1 , y1 ) , ( x2 , y2 ) )
  ( x1 , y1 ) , ( x2 , y2 )
    x1 , y1   ,   x2 , y2

where (x1,y1) and (x2,y2) are any two opposite corners of the box.

Boxes are output using the second syntax.

Any two opposite corners can be supplied on input, but the values will be reordered as needed to store the upper right and lower left corners, in that order.

8.8.5. Paths

Paths are represented by lists of connected points. Paths can be open, where the first and last points in the list are considered not connected, or closed, where the first and last points are considered connected.

Values of type path are specified using any of the following syntaxes:

[ ( x1 , y1 ) , ... , ( xn , yn ) ]
( ( x1 , y1 ) , ... , ( xn , yn ) )
  ( x1 , y1 ) , ... , ( xn , yn )
  ( x1 , y1   , ... ,   xn , yn )
    x1 , y1   , ... ,   xn , yn

where the points are the end points of the line segments comprising the path. Square brackets ([]) indicate an open path, while parentheses (()) indicate a closed path. When the outermost parentheses are omitted, as in the third through fifth syntaxes, a closed path is assumed.

Paths are output using the first or second syntax, as appropriate.

8.8.6. Polygons

Polygons are represented by lists of points (the vertices of the polygon). Polygons are very similar to closed paths; the essential semantic difference is that a polygon is considered to include the area within it, while a path is not.

An important implementation difference between polygons and paths is that the stored representation of a polygon includes its smallest bounding box. This speeds up certain search operations, although computing the bounding box adds overhead while constructing new polygons.

Values of type polygon are specified using any of the following syntaxes:

( ( x1 , y1 ) , ... , ( xn , yn ) )
  ( x1 , y1 ) , ... , ( xn , yn )
  ( x1 , y1   , ... ,   xn , yn )
    x1 , y1   , ... ,   xn , yn

where the points are the end points of the line segments comprising the boundary of the polygon.

Polygons are output using the first syntax.

8.8.7. Circles

Circles are represented by a center point and radius. Values of type circle are specified using any of the following syntaxes:

< ( x , y ) , r >
( ( x , y ) , r )
  ( x , y ) , r
    x , y   , r

where (x,y) is the center point and r is the radius of the circle.

Circles are output using the first syntax.

比较版本

完整来源事实

Representation

{A,B,C}

catalog

{"array_type_name":"_line","array_type_oid":"629","descr":"geometric line, formats '{A,B,C}'/'[point1,point2]'","oid":"628","typacl":"_null_","typalign":"d","typanalyze":"-","typarray":"0","typbasetype":"0","typbyval":"f","typcategory":"G","typcollation":"0","typdefault":"_null_","typdefaultbin":"_null_","typdelim":"','","typelem":"float8","typinput":"line_in","typisdefined":"t","typispreferred":"f","typlen":"24","typmodin":"-","typmodout":"-","typname":"line","typnamespace":"pg_catalog","typndims":"0","typnotnull":"f","typoutput":"line_out","typowner":"POSTGRES","typreceive":"line_recv","typrelid":"0","typsend":"line_send","typstorage":"p","typsubscript":"raw_array_subscript_handler","typtype":"b","typtypmod":"-1"}

operators

map[descr:distance between oid:613 oprcanhash:f oprcanmerge:f oprcode:dist_pl oprcom:<->(line,point) oprjoin:- oprkind:b oprleft:point oprname:<-> oprnamespace:pg_catalog oprnegate:0 oprowner:POSTGRES oprrest:- oprresult:float8 oprright:line], map[descr:distance between oid:760 oprcanhash:f oprcanmerge:f oprcode:dist_lp oprcom:<->(point,line) oprjoin:- oprkind:b oprleft:line oprname:<-> oprnamespace:pg_catalog oprnegate:0 oprowner:POSTGRES oprrest:- oprresult:float8 oprright:point], map[descr:distance between oid:616 oprcanhash:f oprcanmerge:f oprcode:dist_sl oprcom:<->(line,lseg) oprjoin:- oprkind:b oprleft:lseg oprname:<-> oprnamespace:pg_catalog oprnegate:0 oprowner:POSTGRES oprrest:- oprresult:float8 oprright:line], map[descr:distance between oid:762 oprcanhash:f oprcanmerge:f oprcode:dist_ls oprcom:<->(lseg,line) oprjoin:- oprkind:b oprleft:line oprname:<-> oprnamespace:pg_catalog oprnegate:0 oprowner:POSTGRES oprrest:- oprresult:float8 oprright:lseg], map[descr:distance between oid:708 oprcanhash:f oprcanmerge:f oprcode:line_distance oprcom:<->(line,line) oprjoin:- oprkind:b oprleft:line oprname:<-> oprnamespace:pg_catalog oprnegate:0 oprowner:POSTGRES oprrest:- oprresult:float8 oprright:line], map[descr:intersect oid:1537 oprcanhash:f oprcanmerge:f oprcode:inter_sl oprcom:0 oprjoin:- oprkind:b oprleft:lseg oprname:?# oprnamespace:pg_catalog oprnegate:0 oprowner:POSTGRES oprrest:- oprresult:bool oprright:line], map[descr:intersect oid:1539 oprcanhash:f oprcanmerge:f oprcode:inter_lb oprcom:0 oprjoin:- oprkind:b oprleft:line oprname:?# oprnamespace:pg_catalog oprnegate:0 oprowner:POSTGRES oprrest:- oprresult:bool oprright:box], map[descr:point on line oid:1546 oprcanhash:f oprcanmerge:f oprcode:on_pl oprcom:0 oprjoin:- oprkind:b oprleft:point oprname:<@ oprnamespace:pg_catalog oprnegate:0 oprowner:POSTGRES oprrest:- oprresult:bool oprright:line], map[descr:lseg on line oid:1548 oprcanhash:f oprcanmerge:f oprcode:on_sl oprcom:0 oprjoin:- oprkind:b oprleft:lseg oprname:<@ oprnamespace:pg_catalog oprnegate:0 oprowner:POSTGRES oprrest:- oprresult:bool oprright:line], map[descr:closest point to A on B oid:1557 oprcanhash:f oprcanmerge:f oprcode:close_pl oprcom:0 oprjoin:- oprkind:b oprleft:point oprname:## oprnamespace:pg_catalog oprnegate:0 oprowner:POSTGRES oprrest:- oprresult:point oprright:line], map[descr:closest point to A on B oid:1577 oprcanhash:f oprcanmerge:f oprcode:close_ls oprcom:0 oprjoin:- oprkind:b oprleft:line oprname:## oprnamespace:pg_catalog oprnegate:0 oprowner:POSTGRES oprrest:- oprresult:point oprright:lseg], map[descr:intersect oid:1611 oprcanhash:f oprcanmerge:f oprcode:line_intersect oprcom:?#(line,line) oprjoin:- oprkind:b oprleft:line oprname:?# oprnamespace:pg_catalog oprnegate:0 oprowner:POSTGRES oprrest:- oprresult:bool oprright:line], map[descr:parallel oid:1612 oprcanhash:f oprcanmerge:f oprcode:line_parallel oprcom:?||(line,line) oprjoin:- oprkind:b oprleft:line oprname:?|| oprnamespace:pg_catalog oprnegate:0 oprowner:POSTGRES oprrest:- oprresult:bool oprright:line], map[descr:perpendicular oid:1613 oprcanhash:f oprcanmerge:f oprcode:line_perp oprcom:?-|(line,line) oprjoin:- oprkind:b oprleft:line oprname:?-| oprnamespace:pg_catalog oprnegate:0 oprowner:POSTGRES oprrest:- oprresult:bool oprright:line], map[descr:horizontal oid:1614 oprcanhash:f oprcanmerge:f oprcode:line_horizontal oprcom:0 oprjoin:- oprkind:l oprleft:0 oprname:?- oprnamespace:pg_catalog oprnegate:0 oprowner:POSTGRES oprrest:- oprresult:bool oprright:line], map[descr:vertical oid:1615 oprcanhash:f oprcanmerge:f oprcode:line_vertical oprcom:0 oprjoin:- oprkind:l oprleft:0 oprname:?| oprnamespace:pg_catalog oprnegate:0 oprowner:POSTGRES oprrest:- oprresult:bool oprright:line], map[descr:equal oid:1616 oprcanhash:f oprcanmerge:f oprcode:line_eq oprcom:=(line,line) oprjoin:eqjoinsel oprkind:b oprleft:line oprname:= oprnamespace:pg_catalog oprnegate:0 oprowner:POSTGRES oprrest:eqsel oprresult:bool oprright:line], map[descr:intersection point oid:1617 oprcanhash:f oprcanmerge:f oprcode:line_interpt oprcom:#(line,line) oprjoin:- oprkind:b oprleft:line oprname:# oprnamespace:pg_catalog oprnegate:0 oprowner:POSTGRES oprrest:- oprresult:point oprright:line]

来源引用

完整定义与证据 JSON

定义来源

center · PostgreSQL 18 · 555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f

正文语言: en · 555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f