If a static windfield is defined by using Windfield.addpointvne(), the code will crash in Windfield.getdata() line 218: vnorth = ones(npos)*self.vnorth[0,0].

Because self.vnorth is static, I figured it should only contain one element. Can be bypassed by initializing your windfield as a 2D array of size (1,1), e.g. [[0]]. If this is the intended approach, maybe the description of addpointvne() should be altered to more clearly specify the expected input structure.