The different values in a gml:AxisDirectionList indicate the incrementation order to be used on all axes of the grid. Each axis shall be mentioned once and only once.
<simpleType name="AxisDirectionList"><annotation><documentation>The different values in a gml:AxisDirectionList indicate the incrementation order to be used on all axes of the grid. Each axis shall be mentioned once and only once.</documentation></annotation><list itemType="gml:AxisDirection"/></simpleType>