expose mercator projection functions

lib/geom.cc

@@ -1,5 +1,7 @@
 #include <boost/python.hpp>
 
+#include <osmium/geom/mercator_projection.hpp>
+#include <osmium/geom/coordinates.hpp>
 #include <osmium/geom/haversine.hpp>
 #include <osmium/geom/factory.hpp>
 #include <osmium/geom/wkb.hpp>
@@ -38,6 +40,23 @@ BOOST_PYTHON_MODULE(geom)
         "curvature of earth into account. If a :py:class:`WayNodeList` is given "
         "as a parameter the total length of the way in meters is computed.");
 
+    def("lonlat_to_mercator", &osmium::geom::lonlat_to_mercator,
+        arg("coordinate"),
+        "Convert coordinates from WGS84 to Mercator projection.");
+
+    def("mercator_to_lonlat", &osmium::geom::mercator_to_lonlat,
+        arg("coordinate"),
+        "Convert coordinates from WGS84 to Mercator projection.");
+
+    class_<osmium::geom::Coordinates>("Coordinates",
+        "A pair of coordiante values.")
+        .def(init<double, double>())
+        .def(init<osmium::Location const &>())
+        .add_property("x", &osmium::geom::Coordinates::x)
+        .add_property("y", &osmium::geom::Coordinates::y)
+        .def("valid", &osmium::geom::Coordinates::valid,
+             "Coordinates are invalid if they have been default constructed.");
+
     class_<WKBFactory>("WKBFactory",
         "Factory that creates WKB from osmium geometries.")
         .add_property("epsg", &WKBFactory::epsg,

test/test_geom.py

@@ -51,3 +51,22 @@ def area(self, a):
 
     def check_result(self):
         assert_equals(1, len(self.handler.wkbs))
+
+class TestCoordinateConversion(unittest.TestCase):
+
+    def test_lonlat_to_mercator(self):
+        c = o.geom.lonlat_to_mercator(o.geom.Coordinates(0,0))
+        assert_equals(c.x, 0)
+        assert_equals(c.y, 0)
+
+    def test_mercator_lonlat(self):
+        c = o.geom.mercator_to_lonlat(o.geom.Coordinates(0,0))
+        assert_equals(c.x, 0)
+        assert_equals(c.y, 0)
+
+class TestCoordinates(unittest.TestCase):
+
+    def test_coordinate_from_location(self):
+        c = o.geom.Coordinates(o.osm.Location(10.0, -3.0))
+        assert_equals(c.x, 10.0)
+        assert_equals(c.y, -3.0)