The geometric types point, box, lseg, line, path, polygon, and circle have a large set of native support functions and operators, shown in Table 6-20, Table 6-21, and Table 6-22.
Table 6-20. Geometric Operators
Operator | Description | Usage |
---|---|---|
+ | Translation | box '((0,0),(1,1))' + point '(2.0,0)' |
- | Translation | box '((0,0),(1,1))' - point '(2.0,0)' |
* | Scaling/rotation | box '((0,0),(1,1))' * point '(2.0,0)' |
/ | Scaling/rotation | box '((0,0),(2,2))' / point '(2.0,0)' |
# | Intersection | '((1,-1),(-1,1))' # '((1,1),(-1,-1))' |
# | Number of points in path or polygon | # '((1,0),(0,1),(-1,0))' |
## | Point of closest proximity | point '(0,0)' ## lseg '((2,0),(0,2))' |
&& | Overlaps? | box '((0,0),(1,1))' && box '((0,0),(2,2))' |
&< | Overlaps to left? | box '((0,0),(1,1))' &< box '((0,0),(2,2))' |
&> | Overlaps to right? | box '((0,0),(3,3))' &> box '((0,0),(2,2))' |
<-> | Distance between | circle '((0,0),1)' <-> circle '((5,0),1)' |
<< | Left of? | circle '((0,0),1)' << circle '((5,0),1)' |
<^ | Is below? | circle '((0,0),1)' <^ circle '((0,5),1)' |
>> | Is right of? | circle '((5,0),1)' >> circle '((0,0),1)' |
>^ | Is above? | circle '((0,5),1)' >^ circle '((0,0),1)' |
?# | Intersects or overlaps | lseg '((-1,0),(1,0))' ?# box '((-2,-2),(2,2))' |
?- | Is horizontal? | point '(1,0)' ?- point '(0,0)' |
?-| | Is perpendicular? | lseg '((0,0),(0,1))' ?-| lseg '((0,0),(1,0))' |
@-@ | Length or circumference | @-@ path '((0,0),(1,0))' |
?| | Is vertical? | point '(0,1)' ?| point '(0,0)' |
?|| | Is parallel? | lseg '((-1,0),(1,0))' ?|| lseg '((-1,2),(1,2))' |
@ | Contained or on | point '(1,1)' @ circle '((0,0),2)' |
@@ | Center of | @@ circle '((0,0),10)' |
~= | Same as | polygon '((0,0),(1,1))' ~= polygon '((1,1),(0,0))' |
Table 6-21. Geometric Functions
Function | Returns | Description | Example |
---|---|---|---|
area (object) |
double precision | area of item | area(box '((0,0),(1,1))') |
box (box, box) |
box | intersection box | box(box '((0,0),(1,1))',box '((0.5,0.5),(2,2))') |
center (object) |
point | center of item | center(box '((0,0),(1,2))') |
diameter (circle) |
double precision | diameter of circle | diameter(circle '((0,0),2.0)') |
height (box) |
double precision | vertical size of box | height(box '((0,0),(1,1))') |
isclosed (path) |
boolean | a closed path? | isclosed(path '((0,0),(1,1),(2,0))') |
isopen (path) |
boolean | an open path? | isopen(path '[(0,0),(1,1),(2,0)]') |
length (object) |
double precision | length of item | length(path '((-1,0),(1,0))') |
npoints (path) |
integer | number of points | npoints(path '[(0,0),(1,1),(2,0)]') |
npoints (polygon) |
integer | number of points | npoints(polygon '((1,1),(0,0))') |
pclose (path) |
path | convert path to closed | popen(path '[(0,0),(1,1),(2,0)]') |
popen (path) |
path | convert path to open path | popen(path '((0,0),(1,1),(2,0))') |
radius (circle) |
double precision | radius of circle | radius(circle '((0,0),2.0)') |
width (box) |
double precision | horizontal size | width(box '((0,0),(1,1))') |
Table 6-22. Geometric Type Conversion Functions
Function | Returns | Description | Example |
---|---|---|---|
box (circle) |
box | circle to box | box(circle '((0,0),2.0)') |
box (point, point) |
box | points to box | box(point '(0,0)', point '(1,1)') |
box (polygon) |
box | polygon to box | box(polygon '((0,0),(1,1),(2,0))') |
circle (box) |
circle | to circle | circle(box '((0,0),(1,1))') |
circle (point, double
precision) |
circle | point to circle | circle(point '(0,0)', 2.0) |
lseg (box) |
lseg | box diagonal to lseg | lseg(box '((-1,0),(1,0))') |
lseg (point, point) |
lseg | points to lseg | lseg(point '(-1,0)', point '(1,0)') |
path (polygon) |
point | polygon to path | path(polygon '((0,0),(1,1),(2,0))') |
point (circle) |
point | center | point(circle '((0,0),2.0)') |
point (lseg, lseg) |
point | intersection | point(lseg '((-1,0),(1,0))', lseg '((-2,-2),(2,2))') |
point (polygon) |
point | center | point(polygon '((0,0),(1,1),(2,0))') |
polygon (box) |
polygon | 4-point polygon | polygon(box '((0,0),(1,1))') |
polygon (circle) |
polygon | 12-point polygon | polygon(circle '((0,0),2.0)') |
polygon (npts, circle) |
polygon | npts polygon | polygon(12, circle '((0,0),2.0)') |
polygon (path) |
polygon | path to polygon | polygon(path '((0,0),(1,1),(2,0))') |
It is possible to access the two component numbers of a point as though it were an array with subscripts 0, 1. For example, if t.p is a point column then SELECT p[0] FROM t retrieves the X coordinate; UPDATE t SET p[1] = ... changes the Y coordinate. In the same way, a box or an lseg may be treated as an array of two points.