Index: /issm/trunk-jpl/src/m/geometry/SegIntersect.py
===================================================================
--- /issm/trunk-jpl/src/m/geometry/SegIntersect.py	(revision 13352)
+++ /issm/trunk-jpl/src/m/geometry/SegIntersect.py	(revision 13352)
@@ -0,0 +1,83 @@
+import numpy
+from MatlabFuncs import *
+
+def SegIntersect(seg1,seg2):
+	"""
+	SEGINTERSECT - test of segments intersection
+
+	   return 1 if the two segments intersect
+	   seg1=[x1 y1; x2 y2]
+	   seg2=[x1 y1; x2 y2]
+
+	   Usage:
+	      bval=SegIntersect(seg1,seg2)
+	"""
+
+	bval=1
+
+	xA=seg1[0,0]
+	yA=seg1[0,1]
+	xB=seg1[1,0]
+	yB=seg1[1,1]
+	xC=seg2[0,0]
+	yC=seg2[0,1]
+	xD=seg2[1,0]
+	yD=seg2[1,1]
+
+	O2A=numpy.array([xA,yA])-numpy.array([xD/2.+xC/2.,yD/2.+yC/2.])
+	O2B=numpy.array([xB,yB])-numpy.array([xD/2.+xC/2.,yD/2.+yC/2.])
+	O1C=numpy.array([xC,yC])-numpy.array([xA/2.+xB/2.,yB/2.+yA/2.])
+	O1D=numpy.array([xD,yD])-numpy.array([xA/2.+xB/2.,yB/2.+yA/2.])
+
+	n1=numpy.array([yA-yB,xB-xA])    #normal vector to segA
+	n2=numpy.array([yC-yD,xD-xC])    #normal vector to segB
+
+	test1=numpy.dot(n2,O2A)
+	test2=numpy.dot(n2,O2B)
+
+	if test1*test2>0:
+		bval=0
+		return bval
+
+	test3=numpy.dot(n1,O1C)
+	test4=numpy.dot(n1,O1D)
+
+	if test3*test4>0:
+		bval=0
+		return bval
+
+	#if colinear
+	if test1*test2==0 and test3*test4==0 and det(numpy.hstack((n1.reshape((-1,1)),n2.reshape(-1,1))))==0:
+
+		#projection on the axis O1O2
+		O2O1=numpy.array([xA/2.+xB/2.,yB/2.+yA/2.])-numpy.array([xD/2.+xC/2.,yD/2.+yC/2.])
+		O1A=numpy.dot(O2O1,(O2A-O2O1))
+		O1B=numpy.dot(O2O1,(O2B-O2O1))
+		O1C=numpy.dot(O2O1,O1C)
+		O1D=numpy.dot(O2O1,O1D)
+
+		#test if one point is included in the other segment (->bval=1)
+		if (O1C-O1A)*(O1D-O1A)<0:
+			bval=1
+			return bval
+		if (O1C-O1B)*(O1D-O1B)<0:
+			bval=1
+			return bval
+		if (O1A-O1C)*(O1B-O1C)<0:
+			bval=1
+			return bval
+		if (O1A-O1D)*(O1B-O1D)<0:
+			bval=1
+			return bval
+
+		#test if the 2 segments have the same middle (->bval=1)
+		if O2O1==0:
+			bval=1
+			return bval
+
+		#else
+		bval=0
+		return bval
+
+	return bval
+