From 839442aad2e7efdfcb8766a86eaf570035eab8e0 Mon Sep 17 00:00:00 2001
From: Tim Sheerman-Chase <t.sheerman-chase@surrey.ac.uk>
Date: Fri, 31 Aug 2012 22:53:39 +0100
Subject: [PATCH] Improve comments

---
 skimage/transform/_geometric.py | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/skimage/transform/_geometric.py b/skimage/transform/_geometric.py
index 785765d6..9869fd87 100644
--- a/skimage/transform/_geometric.py
+++ b/skimage/transform/_geometric.py
@@ -599,6 +599,18 @@ class PiecewiseAffineTransform(ProjectiveTransform):
         self.triAffines = []
 
     def estimate(self, src, dst):
+        """Set the control points with which to perform the piecewise affine mapping.
+
+        Number of source and destination coordinates must match.
+
+        Parameters
+        ----------
+        src : (N, 2) array
+            Source coordinates.
+        dst : (N, 2) array
+            Destination coordinates.
+
+        """
 
         #Triangulate input positions into mesh
         self.tess = spatial.Delaunay(src)