diff --git a/pages/page.py b/pages/page.py
index 90f3d10..25cbb1a 100644
--- a/pages/page.py
+++ b/pages/page.py
@@ -45,6 +45,25 @@ class Page():
             rotated.append((ox + fc * dx - fs * dy, oy + fs * dx + fc * dy))
         return rotated
 
+    @staticmethod
+    def rhumb(lat1, lon1, lat2, lon2):
+        # Distance in m
+        lon1, lat1, lon2, lat2 = map(radians, [lon1, lat1, lon2, lat2])
+        dlon = lon2 - lon1
+        dlat = lat2 - lat1
+        mlat = (lat1 + lat2) / 2
+        return 6371000 * sqrt(dlat**2 + (cos(mlat) * dlon)**2)
+
+    @staticmethod
+    def haversine(lat1, lon1, lat2, lon2):
+        # Great circle distance in nm
+        lon1, lat1, lon2, lat2 = map(radians, [lon1, lat1, lon2, lat2])
+        dlon = lon2 - lon1
+        dlat = lat2 - lat1
+        a = sin(dlat/2)**2 + cos(lat1) * cos(lat2) * sin(dlon/2)**2
+        c = 2 * asin(sqrt(a))
+        return c * 3440
+
     def __init__(self, pageno, cfg, boatdata):
         self.pageno = pageno
         self.cfg = cfg