From d1629aec0f1a861106d54cb015b238e7fe542936 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johannes=20Sch=C3=B6nberger?= <hannesschoenberger@gmail.com>
Date: Sat, 6 Oct 2012 19:05:11 +0200
Subject: [PATCH] Fix polygon approximation for 0 or less tolerance

---
 skimage/measure/_polygon.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/skimage/measure/_polygon.py b/skimage/measure/_polygon.py
index add4b5fb..7b9b920b 100644
--- a/skimage/measure/_polygon.py
+++ b/skimage/measure/_polygon.py
@@ -28,7 +28,7 @@ def approximate_polygon(coords, tolerance):
     ----------
     .. [1] http://en.wikipedia.org/wiki/Ramer-Douglas-Peucker_algorithm
     """
-    if tolerance == 0:
+    if tolerance <= 0:
         return coords
 
     chain = np.zeros(coords.shape[0], 'bool')