Fix warped images placed behind elliptical map background

Solves GitHub issue #577.

The issue started appearing with `matplotlib` 3.5.0, older versions
of `matplotlib` were behaving as desired.

Author: molinav

CHANGELOG.md

@@ -15,6 +15,10 @@ https://semver.org/spec/v2.0.0.html
 ### Fixed
 - Fix references to removed `numpy.float` alias (solves issue [#589],
   thanks to @quickbrett).
+- Fix bug with elliptical maps causing warped images (Blue Marble,
+  ETOPO, Shaded Relief) to be shown behind the map background when the
+  map boundary is not initialised manually (solves issue [#577], thanks
+  to @YilongWang).
 
 ## [1.3.8] - 2023-08-18
 
@@ -994,6 +998,8 @@ https://github.com/matplotlib/basemap/issues/581
 https://github.com/matplotlib/basemap/pull/580
 [#579]:
 https://github.com/matplotlib/basemap/issues/579
+[#577]:
+https://github.com/matplotlib/basemap/issues/577
 [#573]:
 https://github.com/matplotlib/basemap/issues/573
 [#564]:

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

@@ -3203,7 +3203,7 @@ def set_axes_limits(self,ax=None):
                 # first draw boundary, no fill
                 limb1 = self.drawmapboundary(fill_color='none', ax=ax)
                 # draw another filled patch, with no boundary.
-                limb2 = self.drawmapboundary(linewidth=0, ax=ax)
+                limb2 = self.drawmapboundary(fill_color='none', linewidth=0, ax=ax)
                 self._mapboundarydrawn = limb2
         # for elliptical map, always turn off axis_frame.
         if ((self.projection in ['ortho', 'geos', 'nsper', 'aeqd'] and