X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FGeometry.py;h=2bee60addc97ad27f6cde94d860336b1bf0d105d;hb=d797c850a8493c0027b1e8b8dbc4d3e78840d4d9;hp=89a6cdb929e87bc787574d62396c0fdea21df372;hpb=27ce45a6f4e2844f3d7bc5d570f3cb06e087bb5a;p=dead%2Fcensus-tools.git

diff --git a/src/Geometry.py b/src/Geometry.py
index 89a6cdb..2bee60a 100644
--- a/src/Geometry.py
+++ b/src/Geometry.py
@@ -56,7 +56,23 @@ class TwoVector:
         # If v is neither a TwoVector nor a tuple, we ain't it.
         return False
     
+
+    def __add__(self, other_vector):
+        """
+        Add other_vector to this vector, and return a new TwoVector
+        containing the result.
+        """
+        return TwoVector(self.x + other_vector.x, self.y + other_vector.y)
     
+
+    def __sub__(self, other_vector):
+        """
+        Subtract other_vector from this vector. Return a new
+        TwoVector.
+        """
+        return TwoVector(self.x - other_vector.x, self.y - other_vector.y)
+
+
     def __str__(self):
         """
         Print the contents of our ordered pair.
@@ -85,15 +101,7 @@ class TwoVector:
         return (self.x * other_vector.x) + (self.y * other_vector.y)
 
 
-    def add(self, other_vector):
-        """
-        Add other_vector to this vector, and return a new TwoVector
-        containing the result.
-        """
-        return TwoVector(self.x + other_vector.x, self.y + other_vector.y)
     
-
-        
 class Polygon:
     """
     Wraps shapely.geometry.Polygon.
@@ -145,10 +153,19 @@ class Polygon:
     
     def __str__(self):
         """
-        Write out the well-known text representation of this polygon.
+        Write out the well-known text representation of this polygon,
+        as well as the class name, which helps distinguish
+        Geometry.Polygon from shapely.geometry.Polygon..
         """
         return "Geometry.Polygon<%s>" % self._shapely_polygon.to_wkt()
 
+
+    def wkt(self):
+        """
+        Return just the well-known text for this Polygon.
+        """
+        return self._shapely_polygon.to_wkt()
+
     
     @classmethod
     def from_shapely(self, shapely_polygon):
@@ -187,7 +204,7 @@ class Polygon:
         Translate the self polygon by the TwoVector v.
         """
         regular_coords = self.coords()
-        f = (lambda p: p.add(v))
+        f = (lambda p: p + v)
         translated_coords = map(f, regular_coords)
         return Polygon(translated_coords)
 
@@ -225,8 +242,9 @@ class Polygon:
         # Ex: POLYGON((1 1,5 1,5 5,1 5,1 1),(2 2, 3 2, 3 3, 2 3,2 2))
         if (text.lower().find('polygon') == -1):
             return None
-        
-        return shapely.wkt.loads(text)
+
+        sp = shapely.wkt.loads(text)
+        return Polygon.from_shapely(sp)
 
 
     def drag_rectangle(self, v):
@@ -241,8 +259,8 @@ class Polygon:
         initial_dv = self.drag_vertices(v)
     
         terminal_dv = [0, 0] # Just initializing it.
-        terminal_dv[0] = initial_dv[0].add(v)
-        terminal_dv[1] = initial_dv[1].add(v)
+        terminal_dv[0] = initial_dv[0] + v
+        terminal_dv[1] = initial_dv[1] + v
 
         return Polygon( (initial_dv[1],
                          initial_dv[0],
@@ -252,9 +270,9 @@ class Polygon:
 
     def drag(self, v):
         """
-        Drag this polygon along the line v = (x2-x1, y2-y1), and
+        Drag this polygon along the vector v = (x2-x1, y2-y1), and
         return the new polygon consisting of the union of all points
-        that I've contained along the way.
+        that we've contained along the way.
         """
         terminal_p = self.translate(v)
         dv_rect = self.drag_rectangle(v)