diff --git a/src/analyzer/epoint.py b/src/analyzer/epoint.py
--- a/src/analyzer/epoint.py
+++ b/src/analyzer/epoint.py
@@ -24,12 +24,20 @@ class EPoint:
 		if point.item(0)==0: return None
 		return EPoint(point.item(1)/point.item(0),point.item(2)/point.item(0))
 
+	@staticmethod
+	def fromPolar(point,center):
+		(alpha,length)=point
+		x=math.cos(alpha)
+		y=math.sin(alpha)
+		return length*EPoint(x,y)+center
+
 	def toProjective(self):
 		return (1,self._x,self._y)
 
 	def toPolar(self,center):
 		v=self-center
 		alpha=math.atan2(v.y,v.x)
+		if alpha<0: alpha+=2*math.pi
 		k=self.dist(center)
 		return (alpha,k)