1 files changed, 29 insertions, 0 deletions
diff --git a/content/geometry/spheres.cpp b/content/geometry/spheres.cpp
new file mode 100644
index 0000000..ec22262
--- /dev/null
+++ b/content/geometry/spheres.cpp
@@ -0,0 +1,29 @@
+// Great Circle Distance mit Längen- und Breitengrad.
+double gcDist(double pLat, double pLon,
+	          double qLat, double qLon, double radius) {
+	pLat *= PI / 180; pLon *= PI / 180;
+	qLat *= PI / 180; qLon *= PI / 180;
+	return radius * acos(cos(pLat) * cos(pLon) *
+	                     cos(qLat) * cos(qLon) +
+	                     cos(pLat) * sin(pLon) *
+	                     cos(qLat) * sin(qLon) +
+	                     sin(pLat) * sin(qLat));
+}
+
+// Great Circle Distance mit kartesischen Koordinaten.
+double gcDist(point p, point q) {
+	return acos(p.x * q.x + p.y * q.y + p.z * q.z);
+}
+
+// 3D Punkt in kartesischen Koordinaten.
+struct point{
+	double x, y, z;
+	point() {}
+	point(double x, double y, double z) : x(x), y(y), z(z) {}
+	point(double lat, double lon) {
+		lat *= PI / 180.0; lon *= PI / 180.0;
+		x = cos(lat) * sin(lon);
+		y = cos(lat) * cos(lon);
+		z = sin(lat);
+	}
+};