re class="programlisting">original geometry: (((0, 0), (0, 10), (10, 10), (10, 0)), ((0, 0), (9, 2), (9, 1), (0, 0)), ((0, 0), (2, 9), (1, 9), (0, 0)))
is valid? no
can boost::geometry::correct remedy invalidity? possibly yes
after correction: valid
corrected geometry: (((0, 0), (0, 10), (10, 10), (10, 0), (0, 0)), ((0, 0), (9, 1), (9, 2), (0, 0)), ((0, 0), (2, 9), (1, 9), (0, 0)))

<img src="../../../../img/algorithms/is_valid_failure_example.png" alt="is_valid_failure_example">

</pre>
<h6>
<a name="geome