ADD: new track message, Entity class and Position class

libs/geographiclib/examples/example-Ellipsoid.cpp

@@ -0,0 +1,42 @@
+// Example of using the GeographicLib::Ellipsoid class
+
+#include <iostream>
+#include <iomanip>
+#include <exception>
+#include <GeographicLib/Ellipsoid.hpp>
+
+using namespace std;
+using namespace GeographicLib;
+
+int main() {
+  try {
+    Ellipsoid wgs84(Constants::WGS84_a(), Constants::WGS84_f());
+    // Alternatively: const Ellipsoid& wgs84 = Ellipsoid::WGS84();
+    cout << "The latitude half way between the equator and the pole is "
+         << wgs84.InverseRectifyingLatitude(45) << "\n";
+    cout << "Half the area of the ellipsoid lies between latitudes +/- "
+         << wgs84.InverseAuthalicLatitude(30) << "\n";
+    cout << "The northernmost edge of a square Mercator map is at latitude "
+         << wgs84.InverseIsometricLatitude(180) << "\n";
+    cout << "Table phi(deg)  beta-phi xi-phi mu-phi chi-phi theta-phi (mins)\n"
+         << fixed << setprecision(2);
+    for (int i = 0; i <= 90; i += 15) {
+      double phi = i,
+        bet = wgs84.ParametricLatitude(phi),
+        xi = wgs84.AuthalicLatitude(phi),
+        mu = wgs84.RectifyingLatitude(phi),
+        chi = wgs84.ConformalLatitude(phi),
+        theta = wgs84.GeocentricLatitude(phi);
+      cout << i << " "
+           << (bet-phi)*60 << " "
+           << (xi-phi)*60 << " "
+           << (mu-phi)*60 << " "
+           << (chi-phi)*60 << " "
+           << (theta-phi)*60 << "\n";
+    }
+  }
+  catch (const exception& e) {
+    cerr << "Caught exception: " << e.what() << "\n";
+    return 1;
+  }
+}