controlCurve must contain a gml:Curve element
gml:Curve must have "srsName" attribute set
At least one segment must be a gml:Bezier, gml:LineStringSegment, gml:GeodesicString.
None of the control curve segments can be a gml:ArcByCenterPoint
None of the control curve segments can be a gml:CircleByCenterPoint
None of the control curve segments can be a gml:ArcString
None of the control curve segments can be a gml:Arc
None of the control curve segments can be a gml:Circle
None of the control curve segments can be a gml:ArcStringByBulge
None of the control curve segments can be a gml:ArcByBulge
None of the control curve segments can be a gml:BSpline
None of the control curve segments can be a gml:Clothoid
None of the control curve segments can be a gml:CubicSpline
None of the control curve segments can be a gml:Geodesic (use gml:GeodesicString instead)
None of the control curve segments can be a gml:ArcByCenterPoint
Degree of the Bezier must be "3"
Beziers must have exactly two knots
The value of the first knot must be 1.0
The value of the second knot must be 2.0
Multiplicity of each not must be degree+1 (=4)
Weight of each knot must be 1.0