pgSphere provides some casting
operators. So, you can transform an object to another data
type. A cast is done using a CAST(x AS typename),
x::typename or typename(x)
construct.
Table 5.1. Castings
| casting argument | type target | returns |
|---|---|---|
spoint
|
scircle
|
circle with center position spoint and
radius 0.0
|
spoint
|
sellipse
|
an ellipse at position spoint and
radius 0.0
|
spoint
|
sline
|
a line with length 0.0 at position spoint
|
scircle
|
sellipse
|
the scircle as sellipse
|
sline
|
strans
|
the Euler transformation of sline
|
sellipse
|
scircle
|
the bounding circle of sellipse
|
sellipse
|
strans
|
the Euler transformation of sellipse
|
Example 5.1. Cast a spherical point as a circle
sql> SELECT CAST ( spoint '(10d,20d)' AS scircle );
scircle
--------------------
<(10d , 20d) , 0d>
(1 row)