diff --git a/doc/gtl_polygon_set_concept.htm b/doc/gtl_polygon_set_concept.htm
index 1c461c5..75ee77e 100644
--- a/doc/gtl_polygon_set_concept.htm
+++ b/doc/gtl_polygon_set_concept.htm
@@ -349,6 +349,17 @@ together.
circular arcs. Expected n log n runtime, worst case quadratic
runtime wrt. vertices + intersections.
+
+ template <typename T, typename
+ coord_type>
+ T& simplify(T& polygon_set, distance_type
+ threshold) |
+ Simplify the polygon set by removing vertices that lie
+ within threshold distance of the line segment that
+ connects the two adjacent points in the polygon.
+ Expected n log n runtime, worst case quadratic
+ runtime wrt. vertices + intersections. |
+
template <typename T>
T& scale_up(T& polygon_set, unsigned_area_type factor) |