--- a/python/moving.py	Thu May 23 17:57:11 2013 +0200
+++ b/python/moving.py	Wed Jun 12 17:28:34 2013 -0400
@@ -339,7 +339,7 @@
     The class is iterable'''
 
     def __init__(self, positions=None):
-        if positions != None:
+        if positions:
             self.positions = positions
         else:
             self.positions = [[],[]]
@@ -356,6 +356,12 @@
             t.addPosition(p)
         return t
 
+    def __len__(self):
+        return len(self.positions[0])
+
+    def length(self):
+        return self.__len__()
+
     def __str__(self):
         return ' '.join([self.__getitem__(i).__str__() for i in xrange(self.length())])
 
@@ -376,11 +382,13 @@
             self.iterInstantNum += 1
             return self[self.iterInstantNum-1]
 
-    def length(self):
-        return len(self.positions[0])
+    def setPositionXY(self, i, x, y):
+        if i < self.__len__():
+            self.positions[0][i] = x
+            self.positions[1][i] = y
 
-    def __len__(self):
-        return self.length()
+    def setPosition(self, i, p):
+        self.setPositionXY(i, p.x, p.y)
 
     def addPositionXY(self, x, y):
         self.positions[0].append(x)
@@ -516,6 +524,33 @@
     def normMaxLCSS(t1, t2, threshold):
         return utils.LCSS(t1, t2, threshold, lambda p1, p2: (p1-p2).normMax())
 
+class CurvilinearTrajectory(Trajectory):
+    '''Sub class of trajectory for trajectories with curvilinear coordinates and lane assignements
+    longitudinal coordinate is stored as first coordinate (exterior name S)
+    lateral coordiante is stored as second coordinate'''
+
+    def __init__(self, S = [], Y = [], lanes = []):
+        self.positions = [S,Y]
+        self.lanes = lanes
+        
+    def __getitem__(self,i): 
+        return [self.positions[0][i], self.positions[1][i], self.lanes[i]]
+
+    def getSCoordinates(self):
+        return self.getXCoordinates()
+    
+    def getLanes(self):
+        return self.lanes
+
+    def addPosition(self, s, y, lane):
+        self.addPositionXY(s,y)
+        self.lanes.append(lane)
+
+    def setPosition(self, i, s, y, lane):
+        self.setPositionXY(i, s, y)
+        if i < self.__len__():
+            self.lanes[i] = lane
+
 ##################
 # Moving Objects
 ##################