Added and updated documentation of correct, transform, distance, comparable_distance

[SVN r71153]

doc/src/examples/algorithms/correct.cpp

@@ -0,0 +1,65 @@
+// Boost.Geometry (aka GGL, Generic Geometry Library)
+// QuickBook Example
+
+// Copyright (c) 2011 Barend Gehrels, Amsterdam, the Netherlands.
+
+// Use, modification and distribution is subject to the Boost Software License,
+// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+//[correct
+//` Shows how to correct a polygon with respect to its orientation and closure
+
+#include <iostream>
+
+#include <boost/geometry/geometry.hpp>
+#include <boost/geometry/geometries/adapted/tuple_cartesian.hpp>
+
+#include <boost/assign.hpp>
+
+int main()
+{
+    using boost::assign::tuple_list_of;
+
+    typedef boost::geometry::model::polygon
+        <
+            boost::tuple<int, int>
+        > clockwise_closed_polygon;
+
+    clockwise_closed_polygon cwcp;
+
+    // Fill it counterclockwise (so wrongly), forgetting the closing point
+    boost::geometry::exterior_ring(cwcp) = tuple_list_of(0, 0)(10, 10)(0, 9);
+
+    // Add a counterclockwise closed inner ring (this is correct)
+    boost::geometry::interior_rings(cwcp).push_back(tuple_list_of(1, 2)(4, 6)(2, 8)(1, 2));
+
+    // Its area should be negative (because of wrong orientation)
+    //     and wrong (because of omitted closing point)
+    double area_before = boost::geometry::area(cwcp);
+
+    // Correct it!
+    boost::geometry::correct(cwcp);
+
+    // Check its new area
+    double area_after = boost::geometry::area(cwcp);
+
+    // And output it
+    std::cout << boost::geometry::dsv(cwcp) << std::endl;
+    std::cout << area_before << " -> " << area_after << std::endl;
+
+    return 0;
+}
+
+//]
+
+
+//[correct_output
+/*`
+Output:
+[pre
+(((0, 0), (0, 9), (10, 10), (0, 0)), ((1, 2), (4, 6), (2, 8), (1, 2)))
+-7 -> 38
+]
+*/
+//]