Merge branch 'jmt/magvar'

simgear/magvar/magvar.cxx

@@ -24,6 +24,7 @@
 #include <math.h>
 
 #include <simgear/magvar/magvar.hxx>
+#include <simgear/math/SGMath.hxx>
 
 #include "coremag.hxx"
 #include "magvar.hxx"
@@ -47,6 +48,12 @@ void SGMagVar::update( double lon, double lat, double alt_m, double jd ) {
     magdip = atan(field[5]/sqrt(field[3]*field[3]+field[4]*field[4]));
 }
 
+void SGMagVar::update( const SGGeod& geod, double jd ) {
+
+  update(geod.getLongitudeDeg(), geod.getLatitudeDeg(),
+    geod.getElevationM(), jd);
+}
+
 
 double sgGetMagVar( double lon, double lat, double alt_m, double jd ) {
     // cout << "lat = " << lat << " lon = " << lon << " elev = " << alt_m

simgear/magvar/magvar.hxx

@@ -33,6 +33,9 @@
 #endif
 
 
+// forward decls
+class SGGeod;
+
 /**
  * Magnetic variation wrapper class.
  *
@@ -78,6 +81,11 @@ public:
      */
     void update( double lon, double lat, double alt_m, double jd );
 
+    /**
+     * overloaded variant taking an SGGeod to specify position
+     */
+    void update( const SGGeod& geod, double jd );
+
     /** @return the current magnetic variation in radians. */
     double get_magvar() const { return magvar; }