8.7. Geometric Types
Geometric data types represent two

dimensional spatial objects.
Table 8

16
shows the geometric types available
in PostgreSQL. The most fundamental type, the point, forms th
e basis for all of the other types.
Table 8

16. Geometric Types
Name
Storage Size
Representation
Description
point
16 bytes
Point on the plane
(x,y)
line
32 bytes
Infinite line (not fully implemented)
((x1,y1),(x2,y2))
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 and radius)
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 9.9
.
8.7.1. Points
Points are the fundamental two

dimensional building block for geometric types. Values of type point are specified
using the following syntax:
( x , y )
x , y
where x and y are the respective coordinates as floating

point numbers.
8.7.2. Line Segments
Line segments (lseg) are represented by pairs of points. Values of type lseg are specified using the following
syntax:
( ( 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.
8.7.3. Boxes
Boxes are represented by pairs of points that are opposite corners of the box. Values of type box is specified
using the following syntax:
( ( x1 , y1 ) , ( x2 , y2 ) )
( x1 , y1 ) , (
x2 , y2 )
x1 , y1 , x2 , y2
where (x1,y1) and (x2,y2) are the opposite corners of the box.
Boxes are output using the first syntax. The corners are reordered on input to store the upper right corner, then
the lower left corner. Other corners of
the box can be entered, but the lower left and upper right corners are
determined from the input and stored corners.
8.7.4. Paths
Paths are represented by connected sets of points. Paths can be open, where the first and last points in the set
are not conn
ected, and closed, where the first and last point are connected. The functions popen(p) and
pclose(p) are supplied to force a path to be open or closed, and the functions isopen(p) and isclosed(p) are
supplied to test for either type in an expression.
Val
ues of type path are specified using the following syntax:
( ( 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.
Paths are output using the first syntax.
8.7.5. Polygons
Polygons are represented by sets of points.
Polygons should probably be considered equivalent to closed paths,
but are stored differently and have their own set of support routines.
Values of type polygon are specified using the following syntax:
( ( 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.
8.7.6. Circles
Circl
es are represented by a center point and a radius. Values of type circle are specified using the following
syntax:
< ( x , y ) , r >
( ( x , y ) , r )
( x , y ) , r
x , y , r
where (x,y) is the center and r is the radius of the circle.
Circle
s are output using the first syntax.
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