Merge pull request #145 from nicgowans/master

Float comparison for coincident coordinates in vincenty inverse function

geodepy/geodesy.py

@@ -180,7 +180,8 @@ def vincinv(lat1, lon1, lat2, lon2, ellipsoid=grs80):
     lon2 = angular_typecheck(lon2)
 
     # Exit if the two input points are the same
-    if lat1 == lat2 and lon1 == lon2:
+    tolerance = 0.0000000001
+    if abs(lat1 - lat2) < tolerance and abs(lon1 - lon2) < tolerance:
         return 0, 0, 0
 
     # Equation numbering is from the GDA2020 Tech Manual v1.0

geodepy/tests/test_geodesy.py

@@ -77,6 +77,12 @@ def test_vincinv(self):
         test2 = vincinv(lat1, lon1, lat1, lon1)
         self.assertEqual(test2, (0, 0, 0))
 
+        # Test coincident coordinates (within float precision)
+        pl1 = (-30.645230675, 152.996285475)
+        pl2 = (-30.645230674999997, 152.996285475)
+        test3 = vincinv(pl1[0], pl1[1], pl2[0], pl2[1])
+        self.assertEqual(test3, (0, 0, 0))
+
         # Test DMSAngle Input
         ell_dist, azimuth1to2, azimuth2to1 = vincinv(lat1_DMS, lon1_DMS,
                                                      lat2_DMS, lon2_DMS)

geodepy/transform.py

@@ -269,4 +269,3 @@ def ntv2_2d(ntv2_grid, lat, lon, forward_tf=True, method='bicubic'):
         tf_lon = lon + shifts[1] / 3600
 
     return tf_lat, tf_lon
-