diff --git a/src/Prep/Photo/wgs84offset.cxx b/src/Prep/Photo/wgs84offset.cxx
new file mode 100644
index 00000000..8116da04
--- /dev/null
+++ b/src/Prep/Photo/wgs84offset.cxx
@@ -0,0 +1,37 @@
+// calc wgs84 offset given starting lon/lat/alt, radial and distance
+
+#include <stdlib.h>
+
+#include <simgear/math/sg_geodesy.hxx>
+
+int main( int argc, char **argv ) {
+
+    if ( argc != 6 ) {
+        cout << "bad usage ..." << endl;
+    }
+
+    double lon1 = atof( argv[1] );
+    double lat1 = atof( argv[2] );
+    double alt = atof( argv[3] );
+    double az1 = atof( argv[4] );
+    double s =   atof( argv[5] ) * .3048;
+
+    /**
+     * Given a starting position and an offset radial and distance,
+     * calculate an ending positon on a wgs84 ellipsoid.
+     * @param alt (in) meters
+     * @param lat1 (in) degrees
+     * @param lon1 (in) degrees
+     * @param az1 (in) degrees
+     * @param s (in) distance in meters
+     * @param lat2 (out) degrees
+     * @param lon2 (out) degrees
+     * @param az2 (out) return course in degrees
+     */
+
+    double lat2, lon2, az2;
+
+    geo_direct_wgs_84 ( alt, lat1, lon1, az1, s, &lat2, &lon2, &az2 );
+
+    printf("pos = %.6f %6f\n", lon2, lat2 );
+}