--- a/python/moving.py	Mon Jun 22 15:27:33 2015 +0200
+++ b/python/moving.py	Fri Jun 26 23:49:44 2015 -0400
@@ -122,6 +122,9 @@
         '''Returns the length of the interval'''
         return float(max(0,self.last-self.first+1))
 
+    def __len__(self):
+        return self.length()
+
 # class BoundingPolygon:
 #     '''Class for a polygon bounding a set of points
 #     with methods to create intersection, unions...
@@ -141,11 +144,17 @@
         self.boundingPolygon = boundingPolygon
 
     def empty(self):
-        return self.timeInterval.empty() or not self.boudingPolygon
+        return self.timeInterval.empty()# or not self.boudingPolygon
 
     def getNum(self):
         return self.num
 
+    def __len__(self):
+        return self.timeInterval.length()
+
+    def length(self):
+        return self.timeInterval.length()
+
     def getFirstInstant(self):
         return self.timeInterval.first
 
@@ -1054,9 +1063,6 @@
             print 'The object does not exist at '+str(inter)
             return None
 
-    def length(self):
-        return self.timeInterval.length()
-
     def getPositions(self):
         return self.positions