adds distinction between rotaries/rounabouts

include/util/coordinate_calculation.hpp

@@ -4,6 +4,7 @@
 #include "util/coordinate.hpp"
 
 #include <boost/math/constants/constants.hpp>
+#include <boost/optional.hpp>
 
 #include <utility>
 
@@ -61,6 +62,16 @@ double bearing(const Coordinate first_coordinate, const Coordinate second_coordi
 // Get angle of line segment (A,C)->(C,B)
 double computeAngle(const Coordinate first, const Coordinate second, const Coordinate third);
 
+// find the center of a circle through three coordinates
+boost::optional<Coordinate> circleCenter(const Coordinate first_coordinate,
+                                         const Coordinate second_coordinate,
+                                         const Coordinate third_coordinate);
+
+// find the radius of a circle through three coordinates
+double circleRadius(const Coordinate first_coordinate,
+                    const Coordinate second_coordinate,
+                    const Coordinate third_coordinate);
+
 // factor in [0,1]. Returns point along the straight line between from and to. 0 returns from, 1
 // returns to
 Coordinate interpolateLinear(double factor, const Coordinate from, const Coordinate to);