kml file output for google earth etc

1 files changed, 56 insertions, 0 deletions

diff --git a/core/models/survex.py b/core/models/survex.py
index cdc8a80..f62d93b 100644
--- a/core/models/survex.py
+++ b/core/models/survex.py
@@ -108,6 +108,62 @@ class SurvexStation(models.Model):
 
     def __str__(self):
         return self.name and str(self.name) or "no name"
+        
+    def latlong(self):
+        return utmToLatLng(33, self.x, self.y, northernHemisphere=True)
+        
+import math
+
+def utmToLatLng(zone, easting, northing, northernHemisphere=True):
+    if not northernHemisphere:
+        northing = 10000000 - northing
+
+    a = 6378137
+    e = 0.081819191
+    e1sq = 0.006739497
+    k0 = 0.9996
+
+    arc = northing / k0
+    mu = arc / (a * (1 - math.pow(e, 2) / 4.0 - 3 * math.pow(e, 4) / 64.0 - 5 * math.pow(e, 6) / 256.0))
+
+    ei = (1 - math.pow((1 - e * e), (1 / 2.0))) / (1 + math.pow((1 - e * e), (1 / 2.0)))
+
+    ca = 3 * ei / 2 - 27 * math.pow(ei, 3) / 32.0
+
+    cb = 21 * math.pow(ei, 2) / 16 - 55 * math.pow(ei, 4) / 32
+    cc = 151 * math.pow(ei, 3) / 96
+    cd = 1097 * math.pow(ei, 4) / 512
+    phi1 = mu + ca * math.sin(2 * mu) + cb * math.sin(4 * mu) + cc * math.sin(6 * mu) + cd * math.sin(8 * mu)
+
+    n0 = a / math.pow((1 - math.pow((e * math.sin(phi1)), 2)), (1 / 2.0))
+
+    r0 = a * (1 - e * e) / math.pow((1 - math.pow((e * math.sin(phi1)), 2)), (3 / 2.0))
+    fact1 = n0 * math.tan(phi1) / r0
+
+    _a1 = 500000 - easting
+    dd0 = _a1 / (n0 * k0)
+    fact2 = dd0 * dd0 / 2
+
+    t0 = math.pow(math.tan(phi1), 2)
+    Q0 = e1sq * math.pow(math.cos(phi1), 2)
+    fact3 = (5 + 3 * t0 + 10 * Q0 - 4 * Q0 * Q0 - 9 * e1sq) * math.pow(dd0, 4) / 24
+
+    fact4 = (61 + 90 * t0 + 298 * Q0 + 45 * t0 * t0 - 252 * e1sq - 3 * Q0 * Q0) * math.pow(dd0, 6) / 720
+
+    lof1 = _a1 / (n0 * k0)
+    lof2 = (1 + 2 * t0 + Q0) * math.pow(dd0, 3) / 6.0
+    lof3 = (5 - 2 * Q0 + 28 * t0 - 3 * math.pow(Q0, 2) + 8 * e1sq + 24 * math.pow(t0, 2)) * math.pow(dd0, 5) / 120
+    _a2 = (lof1 - lof2 + lof3) / math.cos(phi1)
+    _a3 = _a2 * 180 / math.pi
+
+    latitude = 180 * (phi1 - fact1 * (fact2 + fact3 + fact4)) / math.pi
+
+    if not northernHemisphere:
+        latitude = -latitude
+
+    longitude = ((zone > 0) and (6 * zone - 183.0) or 3.0) - _a3
+
+    return (latitude, longitude)
 
 #
 # Single SurvexBlock