- elevM = twrNode->getDoubleValue("elev-m");
-
- _tower_location = SGGeod::fromDegM(lon, lat, elevM);
+ elevM = twrNode->getDoubleValue("elev-m");
+// tower elevation is AGL, not AMSL. Since we don't want to depend on the
+// scenery for a precise terrain elevation, we use the field elevation
+// (this is also what the apt.dat code does)
+ double fieldElevationM = geod().getElevationM();
+
+ _tower_location = SGGeod::fromDegM(lon, lat, fieldElevationM + elevM);