Help Center/ GaussDB(DWS)/ SQL Syntax Reference/ SQL Syntax Reference (9.1.0.x)/ Functions and Operators/ Geometric Functions and Operators/ Geometric Type Conversion Functions
Updated on 2024-09-02 GMT+08:00
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Geometric Type Conversion Functions

box(circle)

Description: Circle to box

Return type: box

Example:

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SELECT box(circle '((0,0),2.0)') AS RESULT;
                                  result                                   
---------------------------------------------------------------------------
 (1.41421356237309,1.41421356237309),(-1.41421356237309,-1.41421356237309)
(1 row)

box(point, point)

Description: Points to box

Return type: box

Example:

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SELECT box(point '(0,0)', point '(1,1)') AS RESULT;
   result    
-------------
 (1,1),(0,0)
(1 row)

box(polygon)

Description: Polygon to box

Return type: box

Example:

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SELECT box(polygon '((0,0),(1,1),(2,0))') AS RESULT;
   result    
-------------
 (2,1),(0,0)
(1 row)

circle(box)

Description: Box to circle

Return type: circle

Example:

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SELECT circle(box '((0,0),(1,1))') AS RESULT;
            result             
-------------------------------
 <(0.5,0.5),0.707106781186548>
(1 row)

circle(point, double precision)

Description: Center and radius to circle

Return type: circle

Example:

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SELECT circle(point '(0,0)', 2.0) AS RESULT;
  result   
-----------
 <(0,0),2>
(1 row)

circle(polygon)

Description: Polygon to circle

Return type: circle

Example:

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SELECT circle(polygon '((0,0),(1,1),(2,0))') AS RESULT;
                  result                   
-------------------------------------------
 <(1,0.333333333333333),0.924950591148529>
(1 row)

lseg(box)

Description: Box diagonal to line segment

Return type: lseg

Example:

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SELECT lseg(box '((-1,0),(1,0))') AS RESULT;
     result     
----------------
 [(1,0),(-1,0)]
(1 row)

lseg(point, point)

Description: Points to line segment

Return type: lseg

Example:

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SELECT lseg(point '(-1,0)', point '(1,0)') AS RESULT;
     result     
----------------
 [(-1,0),(1,0)]
(1 row)

path(polygon)

Description: Polygon to path

Return type: path

Example:

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SELECT path(polygon '((0,0),(1,1),(2,0))') AS RESULT;
       result        
---------------------
 ((0,0),(1,1),(2,0))
(1 row)

point(double precision, double precision)

Description: Points

Return type: point

Example:

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SELECT point(23.4, -44.5) AS RESULT;
    result    
--------------
 (23.4,-44.5)
(1 row)

point(box)

Description: Center of box

Return type: point

Example:

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SELECT point(box '((-1,0),(1,0))') AS RESULT;
 result 
--------
 (0,0)
(1 row)

point(circle)

Description: Center of circle

Return type: point

Example:

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SELECT point(circle '((0,0),2.0)') AS RESULT;
 result 
--------
 (0,0)
(1 row)

point(lseg)

Description: Center of line segment

Return type: point

Example:

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SELECT point(lseg '((-1,0),(1,0))') AS RESULT;
 result 
--------
 (0,0)
(1 row)

point(polygon)

Description: Center of polygon

Return type: point

Example:

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SELECT point(polygon '((0,0),(1,1),(2,0))') AS RESULT;
        result         
-----------------------
 (1,0.333333333333333)
(1 row)

polygon(box)

Description: Box to 4-point polygon

Return type: polygon

Example:

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SELECT polygon(box '((0,0),(1,1))') AS RESULT;
          result           
---------------------------
 ((0,0),(0,1),(1,1),(1,0))
(1 row)

polygon(circle)

Description: Circle to 12-point polygon

Return type: polygon

Example:

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SELECT polygon(circle '((0,0),2.0)') AS RESULT;
                                                                                                                                                result                                                                                      

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 ((-2,0),(-1.73205080756888,1),(-1,1.73205080756888),(-1.22464679914735e-16,2),(1,1.73205080756888),(1.73205080756888,1),(2,2.44929359829471e-16),(1.73205080756888,-0.999999999999999),(1,-1.73205080756888),(3.67394039744206e-16,-2),(-0.999999999999999,-1.73205080756888),(-1.73205080756888,-1))
(1 row)

polygon(npts, circle)

Description: Circle to npts-point polygon

Return type: polygon

Example:

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SELECT polygon(12, circle '((0,0),2.0)') AS RESULT;
                                                                                                                                                result                                                                                      

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 ((-2,0),(-1.73205080756888,1),(-1,1.73205080756888),(-1.22464679914735e-16,2),(1,1.73205080756888),(1.73205080756888,1),(2,2.44929359829471e-16),(1.73205080756888,-0.999999999999999),(1,-1.73205080756888),(3.67394039744206e-16,-2),(-0.999999999999999,-1.73205080756888),(-1.73205080756888,-1))
(1 row)

polygon(path)

Description: Path to polygon

Return type: polygon

Example:

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SELECT polygon(path '((0,0),(1,1),(2,0))') AS RESULT;
       result        
---------------------
 ((0,0),(1,1),(2,0))
(1 row)