From 6cf5b62641ad754b05a0f0bab01e0df9be376943 Mon Sep 17 00:00:00 2001
From: Don Gagne <Don@don-laptop.local>
Date: Wed, 3 Jan 2018 18:55:09 -0800
Subject: [PATCH] Fix NaN in calculation

---
 src/QGCGeo.cc | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/QGCGeo.cc b/src/QGCGeo.cc
index bf3f7252b..0c27941cb 100644
--- a/src/QGCGeo.cc
+++ b/src/QGCGeo.cc
@@ -28,7 +28,13 @@
 
 static const float epsilon = std::numeric_limits<double>::epsilon();
 
-void convertGeoToNed(QGeoCoordinate coord, QGeoCoordinate origin, double* x, double* y, double* z) {
+void convertGeoToNed(QGeoCoordinate coord, QGeoCoordinate origin, double* x, double* y, double* z)
+{
+    if (coord == origin) {
+        // Short circuit to prevent NaNs in calculation
+        *x = *y = *z = 0;
+        return;
+    }
 
     double lat_rad = coord.latitude() * M_DEG_TO_RAD;
     double lon_rad = coord.longitude() * M_DEG_TO_RAD;
-- 
2.22.0