Changeset 799

Timestamp:

Jan 27, 2005, 4:20:58 PM (20 years ago)

Author:

ole

Message:

Added populate_polygon and tested it

Location:

inundation/ga/storm_surge/pyvolution

Files:

• test_util.py (modified) (1 diff)
• util.py (modified) (1 diff)

inundation/ga/storm_surge/pyvolution/test_util.py

@@ -511 +511 @@
         
 
+    def test_populate_polygon(self):
+
+        polygon = [[0,0], [1,0], [1,1], [0,1]]
+        points = populate_polygon(polygon, 5)
+
+        assert len(points) == 5
+        for point in points:
+            assert inside_polygon(point, polygon)
+
+
+        #Very convoluted polygon
+        polygon = [[0,0], [10,10], [15,5], [20, 10], [25,0], [30,10], [40,-10]]
+
+        points = populate_polygon(polygon, 5)
+
+        assert len(points) == 5
+        for point in points:
+            assert inside_polygon(point, polygon)
+            
+
                       
 #-------------------------------------------------------------

inundation/ga/storm_surge/pyvolution/util.py

@@ -494 +494 @@
     
 
-
+def populate_polygon(polygon, number_of_points, seed = None):
+    """Populate given polygon with uniformly distributed points.
+
+    Input:
+       polygon - list of vertices of polygon
+       number_of_points - (optional) number of points 
+       seed - seed for random number generator (default=None)
+       
+    Output:
+       points - list of points inside polygon
+       
+    Examples:
+       populate_polygon( [[0,0], [1,0], [1,1], [0,1]], 5 )
+       will return five randomly sleected points inside the unit square 
+    """
+
+    from random import uniform, seed
+
+    seed(seed)
+
+    points = []
+
+    #Find outer extent of polygon
+    max_x = min_x = polygon[0][0]
+    max_y = min_y = polygon[0][1]
+    for point in polygon[1:]:
+        x = point[0] 
+        if x > max_x: max_x = x
+        if x < min_x: min_x = x           
+        y = point[1] 
+        if y > max_y: max_y = y
+        if y < min_y: min_y = y           
+
+
+    while len(points) < number_of_points:     
+        x = uniform(min_x, max_x)
+        y = uniform(min_y, max_y)        
+
+        if inside_polygon( [x,y], polygon ):
+            points.append([x,y])
+
+    return points
 
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