Returns the heading for the specified point of a GeoSequence.
|
Argument … |
Specifies … |
|
index |
the index of the point to return the heading of, where the index of the first point in the GeoSequence is 1. The data type of index is INTEGER. |
Returns a FLOAT value. The value is calculated as the angle (in degrees) between a vertical line and the line segment from the specified point to the next point clockwise from the North.
GeoSequence
CREATE TABLE sample_shapes(skey INTEGER, shape ST_Geometry);
INSERT INTO sample_shapes ( 100,'GeoSequence( (10 10, 15 15, -2 0) ,(2007-03-14 01:35:00, 2007-03-14 01:35:05, 2007-03-14 01:35:08),(1222, 1223, 1224),(2, 12.1, 3.14159, 2.78128, -10, -11, 100.1))' );
SELECT skey
FROM sample_shapes
WHERE ((shape.HeadingN(2)) < 3.8e2)
ORDER BY skey;