sline functions
#To get the beginning and the end of a line, pgSphere provides two functions:
sl_beg( | line); |
sline line;sl_end( | line); |
sline line;Example 6.11. Get the beginning of a line
sql> SELECT sl_beg( sline '(10d, 90d, 270d, ZXZ ), 20d';
You can create a meridian as a line using the function
meridian( | lng); |
float8 lng;
The function returns a line starting at a latitude of
-90° and ending at a latitude of 90°. The line goes
along the given longitude lng in
radians.
Example 6.12. A meridian for longitude 20°
sql> SELECT set_sphere_output('DEG');
set_sphere_output
-------------------
SET DEG
(1 row)
sql> SELECT meridian (20.0 *pi() / 180.0 );
sline
-------------------------------
( 270d, 90d, 20d, ZXZ ), 180d
(1 row)