started adding earth-mapping

some new helper methods
added support for floorplan metadata load/save

geo/EarthMapping.h

@@ -0,0 +1,75 @@
+#ifndef EARTHMAPPING_H
+#define EARTHMAPPING_H
+
+#include "Point3.h"
+#include "EarthPos.h"
+
+/**
+ * mapping between positions on earth and positions within the floorplan
+ */
+class EarthMapping {
+
+private:
+
+	/** one 3D position within the floorplan */
+	Point3 center_map_m;
+
+	/** corresponding 3D position on earth */
+	EarthPos center_earth;
+
+	/** rotation [in degrees] to ensure that the map's y-up-axis points towards the north */
+	float rotation_deg;
+
+	double m_per_deg_lat;
+	double m_per_deg_lon;
+
+
+public:
+
+	void build() {
+
+		// TODO
+
+	}
+
+	/** convert from map-coordinates to earth-coordinates */
+	EarthPos mapToWorld(const Point3 mapPos_m) const {
+
+		Point3 pos = mapPos_m;
+
+		// move to (0,0,0)
+		pos -= center_map_m;
+
+		// undo the rotation
+		const Point2 xy = pos.xy().rotated(-rotation_deg / 180.0 * (float) M_PI);
+
+		// convert this "delta to (0,0,0)" to lon/lat and move it to the lon/lat-center
+		const double lat = cenLat + (xy.y / m_per_deg_lat);
+		const double lon = cenLon + (xy.x / m_per_deg_lon);
+		const float height = pos.z;
+
+		// done
+		return EarthPos(lat, lon, height);
+
+	}
+
+	/** convert from earth-coordinates to map-coordinates */
+	Point3 worldToMap(const EarthPos earthPos) const {
+
+		const double y_m = +(lat-cenLat) * m_per_deg_lat;
+		const double x_m = +(lon-cenLon) * m_per_deg_lon;
+
+		// rotate (our map is axis aligned)
+		Point2 pos(x_m, y_m);
+		pos = pos.rotated(rotDeg / 180 * M_PI);
+
+		// apply movement
+		pos += mapCenter_m;
+
+		return pos;
+
+	}
+
+};
+
+#endif // EARTHMAPPING_H