EndPoint(ls)

Returns the Point that is the endpoint of the LineString value ls.

mysql> SET @ls = 'LineString(1 1,2 2,3 3)';
mysql> SELECT AsText(EndPoint(GeomFromText(@ls)));
+-------------------------------------+
| AsText(EndPoint(GeomFromText(@ls))) |
+-------------------------------------+
| POINT(3 3)                          |
+-------------------------------------+

GLength(ls)

Returns a double-precision number indicating the length of the LineString or MultiLineString value ls in its associated spatial reference. The length of a MultiLineString value is equal to the sum of the lengths of its elements.

mysql> SET @ls = 'LineString(1 1,2 2,3 3)';
mysql> SELECT GLength(GeomFromText(@ls));
+----------------------------+
| GLength(GeomFromText(@ls)) |
+----------------------------+
|         2.8284271247461903 |
+----------------------------+

mysql> SET @mls = 'MultiLineString((1 1,2 2,3 3),(4 4,5 5))';
mysql> SELECT GLength(GeomFromText(@mls));
+-----------------------------+
| GLength(GeomFromText(@mls)) |
+-----------------------------+
|           4.242640687119286 |
+-----------------------------+

GLength() is a nonstandard name. It corresponds to the OpenGIS Length() function. (There is an existing SQL function Length() that calculates the length of string values.)

IsClosed(ls)

For a LineString value ls, IsClosed() returns 1 if ls is closed (that is, its StartPoint() and EndPoint() values are the same).

For a MultiLineString value ls, IsClosed() returns 1 if ls is closed (that is, the StartPoint() and EndPoint() values are the same for each LineString in ls).

IsClosed() returns 0 if ls is not closed, and NULL if ls is NULL.

mysql> SET @ls1 = 'LineString(1 1,2 2,3 3,2 2)';
mysql> SET @ls2 = 'LineString(1 1,2 2,3 3,1 1)';

mysql> SELECT IsClosed(GeomFromText(@ls1));
+------------------------------+
| IsClosed(GeomFromText(@ls1)) |
+------------------------------+
|                            0 |
+------------------------------+

mysql> SELECT IsClosed(GeomFromText(@ls2));
+------------------------------+
| IsClosed(GeomFromText(@ls2)) |
+------------------------------+
|                            1 |
+------------------------------+

mysql> SET @ls3 = 'MultiLineString((1 1,2 2,3 3),(4 4,5 5))';

mysql> SELECT IsClosed(GeomFromText(@ls3));
+------------------------------+
| IsClosed(GeomFromText(@ls3)) |
+------------------------------+
|                            0 |
+------------------------------+

NumPoints(ls)

Returns the number of Point objects in the LineString value ls.

mysql> SET @ls = 'LineString(1 1,2 2,3 3)';
mysql> SELECT NumPoints(GeomFromText(@ls));
+------------------------------+
| NumPoints(GeomFromText(@ls)) |
+------------------------------+
|                            3 |
+------------------------------+

PointN(ls,N)

Returns the N-th Point in the Linestring value ls. Points are numbered beginning with 1.

mysql> SET @ls = 'LineString(1 1,2 2,3 3)';
mysql> SELECT AsText(PointN(GeomFromText(@ls),2));
+-------------------------------------+
| AsText(PointN(GeomFromText(@ls),2)) |
+-------------------------------------+
| POINT(2 2)                          |
+-------------------------------------+

StartPoint(ls)

Returns the Point that is the start point of the LineString value ls.

mysql> SET @ls = 'LineString(1 1,2 2,3 3)';
mysql> SELECT AsText(StartPoint(GeomFromText(@ls)));
+---------------------------------------+
| AsText(StartPoint(GeomFromText(@ls))) |
+---------------------------------------+
| POINT(1 1)                            |
+---------------------------------------+