GML supports two different ways to specify a list of geometric positions: either by a sequence of geometric positions (by reusing the group definition) or a sequence of direct positions (element posList). The posList element allows for a compact way to specify the coordinates of the positions, if all positions are represented in the same coordinate reference system.
<group name="geometricPositionListGroup"><annotation><documentation>GML supports two different ways to specify a list of geometric positions: either by a sequence of geometric positions (by reusing the group definition) or a sequence of direct positions (element posList). The posList element allows for a compact way to specify the coordinates of the positions, if all positions are represented in the same coordinate reference system.</documentation></annotation><choice><element ref="gml:posList"/><group ref="gml:geometricPositionGroup" maxOccurs="unbounded"/></choice></group>