From 3d0115cfa5675f84381531e739f0f7c8df90d37f Mon Sep 17 00:00:00 2001
From: Christoph Deil <Deil.Christoph@gmail.com>
Date: Tue, 11 Jun 2019 23:12:02 +0200
Subject: [PATCH] Remove rotate_polygon function

---
 regions/_geometry/__init__.py       |  2 --
 regions/_geometry/rotate_polygon.py | 40 -----------------------------
 2 files changed, 42 deletions(-)
 delete mode 100644 regions/_geometry/rotate_polygon.py

diff --git a/regions/_geometry/__init__.py b/regions/_geometry/__init__.py
index 097a5b89..c25e9a17 100644
--- a/regions/_geometry/__init__.py
+++ b/regions/_geometry/__init__.py
@@ -2,8 +2,6 @@
 """
 Geometry subpackage for low-level geometry functions.
 """
-
-from .rotate_polygon import *
 from .circular_overlap import *
 from .elliptical_overlap import *
 from .rectangular_overlap import *
diff --git a/regions/_geometry/rotate_polygon.py b/regions/_geometry/rotate_polygon.py
deleted file mode 100644
index afffa776..00000000
--- a/regions/_geometry/rotate_polygon.py
+++ /dev/null
@@ -1,40 +0,0 @@
-# Licensed under a 3-clause BSD style license - see LICENSE.rst
-
-import numpy as np
-
-from astropy import units as u
-from astropy.coordinates.representation import UnitSphericalRepresentation
-
-try:
-    from astropy.coordinates.matrix_utilities import rotation_matrix as rotation_array
-    def rotation_matrix(*args, **kwargs):
-        return np.matrix(rotation_array(*args, **kwargs))
-except ImportError:  # Astropy < 1.3
-    from astropy.coordinates.angles import rotation_matrix
-
-__all__ = ['rotate_polygon']
-
-
-def rotate_polygon(lon, lat, lon0, lat0):
-    """
-    Given a polygon with vertices defined by (lon, lat), rotate the polygon
-    such that the North pole of the spherical coordinates is now at (lon0,
-    lat0). Therefore, to end up with a polygon centered on (lon0, lat0), the
-    polygon should initially be drawn around the North pole.
-    """
-
-    # Create a representation object
-    polygon = UnitSphericalRepresentation(lon=lon, lat=lat)
-
-    # Determine rotation matrix to make it so that the circle is centered
-    # on the correct longitude/latitude.
-    m1 = rotation_matrix(-(0.5 * np.pi * u.radian - lat0), axis='y')
-    m2 = rotation_matrix(-lon0, axis='z')
-    transform_matrix = m2 * m1
-
-    # Apply 3D rotation
-    polygon = polygon.to_cartesian()
-    polygon = polygon.transform(transform_matrix)
-    polygon = UnitSphericalRepresentation.from_cartesian(polygon)
-
-    return polygon.lon, polygon.lat