From 4c4ba8cd1ac84e6ff6ea27dd7204c6ed0889c91e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johannes=20Sch=C3=B6nberger?= <hannesschoenberger@gmail.com>
Date: Thu, 20 Dec 2012 15:08:23 +0100
Subject: [PATCH 1/3] Add default value for polynomial order

---
 skimage/transform/_geometric.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/skimage/transform/_geometric.py b/skimage/transform/_geometric.py
index 1179811d..75ee541a 100644
--- a/skimage/transform/_geometric.py
+++ b/skimage/transform/_geometric.py
@@ -604,7 +604,7 @@ class PolynomialTransform(GeometricTransform):
             raise ValueError("invalid shape of transformation parameters")
         self._params = params
 
-    def estimate(self, src, dst, order):
+    def estimate(self, src, dst, order=2):
         """Set the transformation matrix with the explicit transformation
         parameters.
 
@@ -645,7 +645,7 @@ class PolynomialTransform(GeometricTransform):
             Source coordinates.
         dst : (N, 2) array
             Destination coordinates.
-        order : int
+        order : int, optional
             Polynomial order (number of coefficients is order + 1).
 
         """

From 5fb518b89b76363b8427cad6d3581203fc49ba19 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johannes=20Sch=C3=B6nberger?= <hannesschoenberger@gmail.com>
Date: Thu, 20 Dec 2012 15:08:53 +0100
Subject: [PATCH 2/3] Add test case for default value of polynomial order

---
 skimage/transform/tests/test_geometric.py | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/skimage/transform/tests/test_geometric.py b/skimage/transform/tests/test_geometric.py
index d3a75f7b..c7f9f832 100644
--- a/skimage/transform/tests/test_geometric.py
+++ b/skimage/transform/tests/test_geometric.py
@@ -159,6 +159,12 @@ def test_polynomial_init():
     assert_array_almost_equal(tform2._params, tform._params)
 
 
+def test_polynomial_default_order():
+    tform = estimate_transform('polynomial', SRC, DST)
+    tform2 = estimate_transform('polynomial', SRC, DST, order=2)
+    assert_array_almost_equal(tform2._params, tform._params)
+
+
 def test_union():
     tform1 = SimilarityTransform(scale=0.1, rotation=0.3)
     tform2 = SimilarityTransform(scale=0.1, rotation=0.9)

From 06b852778bad00735a8fd39798baab2f14148c4b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johannes=20Sch=C3=B6nberger?= <hannesschoenberger@gmail.com>
Date: Sat, 22 Dec 2012 22:58:32 +0100
Subject: [PATCH 3/3] Add note about default polynomial order to
 estimate_transform

---
 skimage/transform/_geometric.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/skimage/transform/_geometric.py b/skimage/transform/_geometric.py
index 75ee541a..96ea4687 100644
--- a/skimage/transform/_geometric.py
+++ b/skimage/transform/_geometric.py
@@ -750,7 +750,8 @@ def estimate_transform(ttype, src, dst, **kwargs):
             'affine'            `src, `dst`
             'piecewise-affine'  `src, `dst`
             'projective'        `src, `dst`
-            'polynomial'        `src, `dst`, `order` (polynomial order)
+            'polynomial'        `src, `dst`, `order` (polynomial order,
+                                                      default order is 2)
 
         Also see examples below.