The five GKS Marker types, point, plus, asterisk, circle
and cross ('GPOINT', 'GPLUS', 'GAST', 'GOMARK', 'GXMARK'),
are demonstrated in 
.
For example:
CALL GSMK(GPOINT) - sets the marker type to point
Figure: GKS marker types
Markers may be scaled in size by calling GSMKSC. For example:
CALL GSMKSC(3.5)will scale the following markers by 3.5 times. The implementation of this function is workstation-dependent. In particular, markers drawn on terminals by hardware may only exist in certain fixed sizes.