Merge branch 'bugfix-mpl38-upgrade' into develop

Author: molinav

CHANGELOG.md

@@ -36,6 +36,7 @@ https://semver.org/spec/v2.0.0.html
     - Upgrade `pillow` upper limit to 10.2.0.
 - Update library dependencies:
   - Upgrade upper limit for `numpy` to 1.27.0.
+  - Upgrade upper limit for `matplotlib` to 3.9.0.
   - Downgrade upper limit for `pyproj` to 2.2.0 for Python 2.7.
   - Set dependency on `packaging` as replacement for `distutils`.
 - Update build dependencies:
@@ -71,6 +72,10 @@ https://semver.org/spec/v2.0.0.html
   Clang 16 and GCC 14 (PR [#595] by @fweimer-rh).
 - Apply basic cleanup of `_geoslib.pyx` source code (i.e. basic linting,
   removal of commented code, version update).
+- Fix breaking change from `matplotlib` 3.8 due to the promotion of
+  `QuadContourSet` objects into `Artist` objects, which affected
+  `Basemap.contour`, `Basemap.contourf` and `Basemap.nightshade`
+  (solves issue [#594], thanks to @qianwu2 and @rcomer).
 
 ### Removed
 - Attribute `__version__` in `mpl_toolkits.basemap.proj` module.
@@ -1076,6 +1081,8 @@ https://semver.org/spec/v2.0.0.html
 
 [#595]:
 https://github.com/matplotlib/basemap/pull/595
+[#594]:
+https://github.com/matplotlib/basemap/issues/594
 [#593]:
 https://github.com/matplotlib/basemap/pull/593
 [#592]:

packages/basemap/requirements.txt

@@ -18,7 +18,7 @@ matplotlib >= 1.5, < 3.0; python_version == "2.7"
 matplotlib >= 1.5, < 2.0; python_version == "3.2"
 matplotlib >= 1.5, < 2.0; python_version == "3.3"
 matplotlib >= 1.5, < 3.0; python_version == "3.4"
-matplotlib >= 1.5, < 3.8; python_version >= "3.5"
+matplotlib >= 1.5, < 3.9; python_version >= "3.5"
 
 pyproj >= 1.9.3, < 2.1.0; python_version == "2.6"
 pyproj >= 1.9.3, < 2.2.0; python_version == "2.7"

packages/basemap/src/mpl_toolkits/basemap/__init__.py

@@ -31,6 +31,7 @@
 import numpy.ma as ma
 
 import matplotlib as mpl
+from matplotlib.artist import Artist
 from matplotlib.collections import LineCollection
 from matplotlib.collections import PolyCollection
 from matplotlib.image import imread
@@ -3592,7 +3593,11 @@ def contour(self,x,y,data,*args,**kwargs):
         # set axes limits to fit map region.
         self.set_axes_limits(ax=ax)
         # clip to map limbs
-        CS.collections,c = self._cliplimb(ax,CS.collections)
+        if isinstance(CS, Artist):
+            # Since MPL 3.8, `QuadContourSet` objects are `Artist` objects too.
+            CS, c = self._cliplimb(ax, CS)
+        else:
+            CS.collections, c = self._cliplimb(ax, CS.collections)
         return CS
 
     @_transform
@@ -3688,7 +3693,11 @@ def contourf(self,x,y,data,*args,**kwargs):
         # set axes limits to fit map region.
         self.set_axes_limits(ax=ax)
         # clip to map limbs
-        CS.collections,c = self._cliplimb(ax,CS.collections)
+        if isinstance(CS, Artist):
+            # Since MPL 3.8, `QuadContourSet` objects are `Artist` objects too.
+            CS, c = self._cliplimb(ax, CS)
+        else:
+            CS.collections, c = self._cliplimb(ax, CS.collections)
         return CS
 
     @_transformuv
@@ -4733,12 +4742,18 @@ def nightshade(self,date,color="k",delta=0.25,alpha=0.5,ax=None,zorder=2):
         # contour the day-night grid, coloring the night area
         # with the specified color and transparency.
         CS = self.contourf(x,y,daynight,1,colors=[color],alpha=alpha,ax=ax)
-        # set zorder on ContourSet collections show night shading
-        # is on top.
-        for c in CS.collections:
-            c.set_zorder(zorder)
-        # clip to map limbs
-        CS.collections,c = self._cliplimb(ax,CS.collections)
+        if isinstance(CS, Artist):
+            # Since MPL 3.8, `QuadContourSet` objects are `Artist` objects too.
+            CS.set_zorder(zorder)
+            # clip to map limbs
+            CS, c = self._cliplimb(ax, CS)
+        else:
+            # set zorder on ContourSet collections show night shading
+            # is on top.
+            for c in CS.collections:
+                c.set_zorder(zorder)
+            # clip to map limbs
+            CS.collections, c = self._cliplimb(ax, CS.collections)
         return CS
 
     def _check_ax(self):

packages/basemap/test/mpl_toolkits/basemap/test_Basemap.py

@@ -1,5 +1,6 @@
 """Import test for the :mod:`mpl_toolkits.basemap.Basemap` class."""
 
+import datetime as dt
 try:
     import unittest2 as unittest
 except ImportError:
@@ -9,6 +10,7 @@
 import matplotlib as mpl
 import matplotlib.pyplot as plt
 from matplotlib.collections import LineCollection
+from matplotlib.contour import QuadContourSet
 from matplotlib.image import AxesImage
 from matplotlib.patches import Polygon
 from mpl_toolkits.basemap import Basemap
@@ -204,6 +206,48 @@ def test_shadedrelief_with_custom_axes(self):
         _, axs = plt.subplots()
         self.test_shadedrelief(axs=axs, axslen0=10)
 
+    def _test_generic_contour_function(self, function):
+        """Generic test for the `contour` and `contourf` methods."""
+
+        bmap = Basemap(projection="ortho", lat_0=45, lon_0=-100, resolution=None)
+
+        # Create a regular lat/lon grid.
+        nlats = 73
+        nlons = 145
+        delta = 2 * np.pi / (nlons - 1)
+        indx = np.indices((nlats, nlons))
+        lats = (0.5 * np.pi - delta * indx[0, :, :])
+        lons = (delta * indx[1, :, :])
+
+        # Create some data the regular lat/lon grid.
+        mean = 0.50 * np.cos(2 * lats) * ((np.sin(2 * lats))**2 + 2)
+        wave = 0.75 * np.cos(4 * lons) * np.sin(2 * lats)**8
+        data = mean + wave
+
+        # Compute native map projection coordinates of lat/lon grid.
+        x, y = bmap(np.degrees(lons), np.degrees(lats))
+
+        # Contour data over the map and check output.
+        cset = getattr(bmap, function)(x, y, data, 15)
+        self.assertIsInstance(cset, QuadContourSet)
+
+    def test_contour(self):
+        """Test drawing contours on a map."""
+
+        self._test_generic_contour_function("contour")
+
+    def test_contourf(self):
+        """Test drawing filled contours on a map."""
+
+        self._test_generic_contour_function("contourf")
+
+    def test_nightshade(self):
+        """Test drawing the day/night terminator and night shade on a map."""
+
+        bmap = Basemap(projection="mill", lon_0=180)
+        cset = bmap.nightshade(date=dt.datetime(1970, 1, 1))
+        self.assertIsInstance(cset, QuadContourSet)
+
 
 class TestMplToolkitsBasemapBasemapCall(unittest.TestCase):
     """Unittest class for :meth:`mpl_toolkits.basemap.Basemap.__call__`."""