spoint functions
#The functions
long( | p); |
spoint p;lat( | p); |
spoint p;
returns the longitude or latitude value of a
spherical position p in radians.
Example 6.2. Get the longitude and latitude of a spherical point in degrees
sql> SELECT long ( spoint '(10d,20d)' ) * 180.0 / pi() AS longitude;
longitude
------------
10
(1 row)
sql> SELECT lat ( spoint '(10d,20d)' ) * 180.0 / pi() AS latitude;
latitude
----------
20
(1 row)
The functions
x( | p); |
spoint p;y( | p); |
spoint p;z( | p); |
spoint p;
return the Cartesian
x, y or
z value of a spherical position
p. The returned values are always
between -1.0 and +1.0.
Example 6.3.
Get the Cartesian z-value
of a spherical point
sql> SELECT z ( spoint '(10d,-90d)' ) AS z;
z
----
-1
(1 row)
You can get a float8 array of Cartesian values using the function
xyz( | p); |
spoint p;Example 6.4. Get the Cartesian values of a spherical point
sql> SELECT xyz ( spoint '(0d,0d)' ) AS cart;
cart
---------
{1,0,0}
(1 row)