If markerUnits="userSpaceOnUse", ‘markerWidth’, ‘markerHeight’ and the contents of the ‘marker’ represent values in the current user coordinate system in place for the graphic object referencing the marker (i.e., the user coordinate system for the element referencing the ‘marker’ element via a ‘marker’, ‘marker-start’, ‘marker-mid’ or ‘marker-end’ property).
UserSpaceOnUse = 1