Changeset 8057

Timestamp:

Oct 30, 2010, 5:51:31 PM (12 years ago)

Author:

steve

Message:

Added a 'closed' argument to read_polygon so that the code correctly tests for a self intersecting polygon (both open and closed)

File:

• trunk/anuga_core/source/anuga/geometry/polygon.py (modified) (4 diffs)

trunk/anuga_core/source/anuga/geometry/polygon.py

@@ -350 +350 @@
     return bool(_is_inside_triangle(point, triangle, int(closed), rtol, atol))
     
-def is_complex(polygon, verbose=False):
+def is_complex(polygon, closed=True, verbose=False):
     """Check if a polygon is complex (self-intersecting).
        Uses a sweep algorithm that is O(n^2) in the worst case, but
@@ -378 +378 @@
     for i in range(0, len(polygon)-1):
         unsorted_segs.append([list(polygon[i]), list(polygon[i+1])])
-    unsorted_segs.append([list(polygon[0]), list(polygon[-1])])
+
+    if closed:
+        unsorted_segs.append([list(polygon[0]), list(polygon[-1])])
     
     # all segments must point in same direction
@@ -855 +857 @@
 ################################################################################
 
-def read_polygon(filename, delimiter=','):
-    """ Read points assumed to form a polygon.
-
-        Also checks to make sure polygon is not complex (self-intersecting).
+def read_polygon(filename, delimiter=',', closed='True'):
+    """ Read points assumed to form a (closed) polygon.
+        Can also be used toread  in a polyline (closed = 'False')
+
+        Also checks to make sure polygon (polyline)
+        is not complex (self-intersecting).
 
         filename Path to file containing polygon data.
@@ -876 +880 @@
         polygon.append([float(fields[0]), float(fields[1])])
     
-    # check this is a valid polygon. 
-    if is_complex(polygon, verbose=True):    
+    # check this is a valid polygon (polyline).
+    if is_complex(polygon, closed, verbose=True):
         msg = 'ERROR: Self-intersecting polygon detected in file '
         msg += filename +'. A complex polygon will not '