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 |
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| 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 |
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| 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. |
