PointZ and PointM Data Types
PointZ and PointM have the same properties as the Point data type except they contain one more ordinate. The Z is the elevation and the M is the measurement. Syntactically these types are similar.
Examples:
Without specifying SRID:
CREATE TABLE houses (id VARCHAR(30), location POINTZ);
CREATE TABLE treees (id VARCHAR(30), location POINTM);
With specifying SRID:
CREATE TABLE houses (id VARCHAR(30), location POINTZ SRID 4326);
CREATE TABLE treees (id VARCHAR(30), location POINTM SRID 4326);
Use X, Y, and Z coordinates to represent houses:
CREATE TABLE houses (id INTEGER PRIMARY KEY, location POINTZ NOT NULL );
INSERT INTO houses (id, location) VALUES (1, GEOMFROMTEXT('POINTZ(5 10 150)'));
Use X, Y, and M coordinates to represent trees, where M is the height of the tree in meters:
CREATE TABLE trees (id INTEGER PRIMARY KEY, location POINTM NOT NULL );
INSERT INTO trees (id, location) VALUES (1, GEOMFROMTEXT('POINTM(5 10 15)'));