Add a test for EarthDistanceSmall()

The numbers are a bit iffy, but way better than anything I could find
on the web.  Maybe.

1 files changed, 71 insertions, 0 deletions

diff --git a/test_misc.py b/test_misc.py
new file mode 100755
index 00000000..c39a9304
--- /dev/null
+++ b/test_misc.py
@@ -0,0 +1,71 @@
+#!/usr/bin/env python
+#
+# Test gps/misc.py
+#
+
+# This code runs compatibly under Python 2 and 3.x for x >= 2.
+# Preserve this property!
+from __future__ import absolute_import, print_function, division
+
+import sys, gps.misc
+
+errors = 0
+# values from here: https://en.wikipedia.org/wiki/Decimal_degrees#Precision
+# Note the wikipedia numbers are NOT ellipsoid corrected:
+# EarthDistanceSmall() is ellipsoid corrected.
+#
+# I suspect these numbers are not quite right
+# someone will promptly correct me?
+tests = [
+    # equator 1 degree
+    (  0.00000000, 0.00000000,  1.00000000, 0.00000000, 110574),
+    (  0.00000000, 0.00000000,  0.00000000, 1.00000000, 110574),
+    (  0.00000000, 0.00000000,  1.00000010, 1.00000000, 156372),
+    # 23N 1 degree
+    ( 23.00000000, 0.00000000, 24.00000000, 0.00000000, 110751),
+    ( 23.00000000, 0.00000000, 23.00000000, 1.00000000, 101940),
+    ( 23.00000000, 0.00000000, 24.00000000, 1.00000000, 150270),
+    # 45N 1 degree
+    ( 45.00000000, 0.00000000, 46.00000000, 0.00000000, 111141),
+    ( 45.00000000, 0.00000000, 45.00000000, 1.00000000,  78582),
+    ( 45.00000000, 0.00000000, 46.00000000, 1.00000000, 135723),
+    # 67N 1 degree
+    ( 67.00000000, 0.00000000, 68.00000000, 0.00000000, 111528),
+    ( 67.00000000, 0.00000000, 67.00000000, 1.00000000,  43575),
+    ( 67.00000000, 0.00000000, 68.00000000, 1.00000000, 119416),
+    # equator 10e-7
+    (  0.00000000, 0.00000000,  0.00000010, 0.00000000, 0.011057),
+    (  0.00000000, 0.00000000,  0.00000000, 0.00000010, 0.011057),
+    (  0.00000000, 0.00000000,  0.00000010, 0.00000010, 0.015638),
+    # 23N 10e-7
+    ( 23.00000000, 0.00000000, 23.00000010, 0.00000000, 0.011074),
+    ( 23.00000000, 0.00000000, 23.00000000, 0.00000010, 0.010194),
+    ( 23.00000000, 0.00000000, 23.00000010, 0.00000010, 0.015052),
+    # 45N 10e-7
+    ( 45.00000000, 0.00000000, 45.00000010, 0.00000000, 0.011113),
+    ( 45.00000000, 0.00000000, 45.00000000, 0.00000010, 0.007858),
+    ( 45.00000000, 0.00000000, 45.00000010, 0.00000010, 0.013611),
+    # 67N 10e-7
+    ( 67.00000000, 0.00000000, 67.00000010, 0.00000000, 0.011152),
+    ( 67.00000000, 0.00000000, 67.00000000, 0.00000010, 0.0043575),
+    ( 67.00000000, 0.00000000, 67.00000010, 0.00000010, 0.011973),
+]
+
+# EarthDistanceSmall
+for ( lat1, lon1, lat2, lon2, dist) in tests :
+    distance = gps.misc.EarthDistanceSmall( (lat1, lon1), (lat2, lon2))
+    # compare to 0.01%
+    diff = dist - distance
+    max_diff = dist * 0.0001
+    if abs( diff ) > max_diff:
+        sys.stderr.write( \
+            "misc test: %.8f %.8f, %.8f %.8f, expected %.7f got %.7f\n" \
+            % (lat1, lon1, lat2, lon2, dist, distance))
+        errors += 1
+    else:
+        print("OK" )
+
+if errors:
+    sys.exit(1)
+else:
+    sys.exit(0)