long setWeight(string ck, float w, bool isFixed)

This method sets the weight (thickness) of the line with CARIS Key ck to wIf isFixed is FALSE, the line weight is taken to be millimeters on the surface of the Earth.  This means the line will thicken as the user zooms in.  Otherwise, the line weight is taken to be pixels relative to the view.  This means the thickness will remain constant as the user zooms in.

This method returns zero upon success, and returns an error code if