diff --git a/lib/iris/analysis/cartography.py b/lib/iris/analysis/cartography.py
index f103549d4e..8d047203ce 100644
--- a/lib/iris/analysis/cartography.py
+++ b/lib/iris/analysis/cartography.py
@@ -599,6 +599,12 @@ def project(cube, target_proj, nx=None, ny=None):
         on the statistics of the data e.g. the mean and standard deviation
         will not be preserved.
 
+    .. warning::
+
+        If the target projection is non-rectangular, e.g. Robinson, the target
+        grid may include points outside the boundary of the projection. The
+        latitude/longitude of such points may be unpredictable.
+
     """
     try:
         lon_coord, lat_coord = _get_lon_lat_coords(cube)
diff --git a/lib/iris/plot.py b/lib/iris/plot.py
index 9dff582bc4..1d4286aa84 100644
--- a/lib/iris/plot.py
+++ b/lib/iris/plot.py
@@ -441,6 +441,11 @@ def _draw_2d_from_bounds(draw_method_name, cube, *args, **kwargs):
                     values = np.arange(data.shape[data_dim] + 1) - 0.5
                 else:
                     values = coord.contiguous_bounds()
+                    values = _fixup_dates(coord, values)
+                    if values.dtype == np.dtype(object) and isinstance(
+                        values[0], datetime.datetime
+                    ):
+                        values = mpl_dates.date2num(values)
 
             plot_arrays.append(values)
 
diff --git a/lib/iris/quickplot.py b/lib/iris/quickplot.py
index 147f119fd3..0e24ba5f1d 100644
--- a/lib/iris/quickplot.py
+++ b/lib/iris/quickplot.py
@@ -14,6 +14,7 @@
 """
 
 import cf_units
+from matplotlib import __version__ as mpl_version
 import matplotlib.pyplot as plt
 
 import iris.config
@@ -46,6 +47,13 @@ def _title(cube_or_coord, with_units):
 
             if _use_symbol(units):
                 units = units.symbol
+            if units.is_time_reference():
+                # iris.plot uses matplotlib.dates.date2num, which is fixed to the below unit.
+                if mpl_version >= "3.3":
+                    days_since = "1970-01-01"
+                else:
+                    days_since = "0001-01-01"
+                units = "days since {}".format(days_since)
             title += " / {}".format(units)
 
     return title
diff --git a/lib/iris/tests/experimental/test_raster.py b/lib/iris/tests/experimental/test_raster.py
index 44a2857645..80ff725120 100644
--- a/lib/iris/tests/experimental/test_raster.py
+++ b/lib/iris/tests/experimental/test_raster.py
@@ -77,6 +77,10 @@ def _check_tiff_export(self, masked, inverted=False):
             339,
             33550,
             33922,
+            42113,
+            # Don't add a check entry for this, as coding changed between gdal
+            # version 1 and 2.
+            # tif_header_entries[42113] = (u'1e+20',)
         ]
         tif_header_entries = {
             256: (160,),
@@ -130,12 +134,6 @@ def _check_tiff_export(self, masked, inverted=False):
             # Mask some of the data + expect a slightly different header...
             cube.data = np.ma.masked_where(cube.data <= 380, cube.data)
 
-            # There is an additional key..
-            tif_header_keys += [42113]
-            # Don't add a check entry for this, as coding changed between gdal
-            # version 1 and 2, *and* between Python2 and Python3.
-            # tif_header_entries[42113] = (u'1e+20',)
-
         if inverted:
             # Check with the latitude coordinate (and the corresponding
             # cube.data) inverted.
diff --git a/lib/iris/tests/integration/plot/test_plot_2d_coords.py b/lib/iris/tests/integration/plot/test_plot_2d_coords.py
index 7883fd713a..0054340976 100644
--- a/lib/iris/tests/integration/plot/test_plot_2d_coords.py
+++ b/lib/iris/tests/integration/plot/test_plot_2d_coords.py
@@ -43,14 +43,14 @@ def test_2d_coord_bounds_platecarree(self):
         cube = simple_cube_w_2d_coords()[0, 0]
         ax = plt.axes(projection=ccrs.PlateCarree(central_longitude=180))
         qplt.pcolormesh(cube)
-        ax.coastlines(color="red")
+        ax.coastlines(resolution="110m", color="red")
         self.check_graphic()
 
     def test_2d_coord_bounds_northpolarstereo(self):
         cube = simple_cube_w_2d_coords()[0, 0]
         ax = plt.axes(projection=ccrs.NorthPolarStereo())
         qplt.pcolormesh(cube)
-        ax.coastlines(color="red")
+        ax.coastlines(resolution="110m", color="red")
         self.check_graphic()
 
 
@@ -71,7 +71,7 @@ def test_2d_coords_contour(self):
         cube.add_aux_coord(co_x, (0, 1))
         ax = plt.axes(projection=ccrs.PlateCarree())
         qplt.contourf(cube)
-        ax.coastlines(color="red")
+        ax.coastlines(resolution="110m", color="red")
         ax.gridlines(draw_labels=True)
         ax.set_extent((0, 180, 0, 90))
         self.check_graphic()
diff --git a/lib/iris/tests/integration/plot/test_vector_plots.py b/lib/iris/tests/integration/plot/test_vector_plots.py
index 19a5a60c2d..e811efd015 100644
--- a/lib/iris/tests/integration/plot/test_vector_plots.py
+++ b/lib/iris/tests/integration/plot/test_vector_plots.py
@@ -121,7 +121,7 @@ def test_2d_plain_latlon(self):
         self.plot(
             "latlon_2d", u_cube, v_cube, coords=("longitude", "latitude")
         )
-        ax.coastlines(color="red")
+        ax.coastlines(resolution="110m", color="red")
         ax.set_global()
         self.check_graphic()
 
@@ -132,7 +132,7 @@ def test_2d_plain_latlon_on_polar_map(self):
         self.plot(
             "latlon_2d_polar", u_cube, v_cube, coords=("longitude", "latitude")
         )
-        ax.coastlines(color="red")
+        ax.coastlines(resolution="110m", color="red")
         self.check_graphic()
 
     def test_2d_rotated_latlon(self):
@@ -142,7 +142,7 @@ def test_2d_rotated_latlon(self):
         self.plot(
             "2d_rotated", u_cube, v_cube, coords=("longitude", "latitude")
         )
-        ax.coastlines(color="red")
+        ax.coastlines(resolution="110m", color="red")
         ax.set_global()
         self.check_graphic()
 
diff --git a/lib/iris/tests/results/imagerepo.json b/lib/iris/tests/results/imagerepo.json
index a353507d12..f9430ae9f5 100644
--- a/lib/iris/tests/results/imagerepo.json
+++ b/lib/iris/tests/results/imagerepo.json
@@ -6,7 +6,8 @@
     "gallery_tests.test_plot_COP_maps.TestCOPMaps.test_plot_cop_maps.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/ea9138db95668524913e6ac168997e85957e917e876396b96a81b5ce3c496935.png",
         "https://scitools.github.io/test-iris-imagehash/images/v4/ea9130db95668524913c6ac178995b0d956e917ec76396b96a853dcf94696935.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/ea9130db95668524913e6ac168991f0d956e917ec76396b96a853dcf94796931.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/ea9130db95668524913e6ac168991f0d956e917ec76396b96a853dcf94796931.png",
+        "https://scitools.github.io/test-iris-imagehash/images/v4/ea9130db95668524913d6ac168991f0d956e917ec76396b96a853dcf94696935.png"
     ],
     "gallery_tests.test_plot_SOI_filtering.TestSOIFiltering.test_plot_soi_filtering.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/fac460b9c17b78723e05a5a9954edaf062332799954e9ca5c63b9a52d24e5a95.png",
@@ -21,7 +22,8 @@
     ],
     "gallery_tests.test_plot_anomaly_log_colouring.TestAnomalyLogColouring.test_plot_anomaly_log_colouring.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/ec4464e185a39f93931e9b1e91696d2949dde6e63e26a47a5ad391938d9a5a0c.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/ecc164e78e979b19b3789b0885a564a56cc2c65e3ec69469db1bdb9a853c1e24.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/ecc164e78e979b19b3789b0885a564a56cc2c65e3ec69469db1bdb9a853c1e24.png",
+        "https://scitools.github.io/test-iris-imagehash/images/v4/ece164e68e979b19b3781b0885a564a56ccac65e3ec69469db1bdb9a853c1e24.png"
     ],
     "gallery_tests.test_plot_atlantic_profiles.TestAtlanticProfiles.test_plot_atlantic_profiles.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/9f8260536bd28e1320739437b5f437b0a51d66f4cc5d08fcd00fdb1c93fcb21c.png",
@@ -35,7 +37,7 @@
         "https://scitools.github.io/test-iris-imagehash/images/v4/eeea64dd6ea8cd99991f1322b3761e06845718d89995b3131f32a4765ec2a1cd.png",
         "https://scitools.github.io/test-iris-imagehash/images/v4/eeea64dd6ea8cd99991d1322b3741e2684571cd89995b3131f32a4765ee2a1cc.png"
     ],
-         "gallery_tests.test_plot_coriolis.TestCoriolisPlot.test_plot_coriolis.0": [
+    "gallery_tests.test_plot_coriolis.TestCoriolisPlot.test_plot_coriolis.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/e78665de9a699659e55e9965886979966986c5e63e98c19e3a256679e1981a24.png",
         "https://scitools.github.io/test-iris-imagehash/images/v4/e68665de9a699659c1fe99a5896965966996c46e3e19c1da3a652669c51e1a26.png"
     ],
@@ -48,8 +50,7 @@
         "https://scitools.github.io/test-iris-imagehash/images/v4/ea9521fb956a394068931e9be07e4aa5856cc47e4a91957a1ba55bb5b17a3b81.png"
     ],
     "gallery_tests.test_plot_custom_aggregation.TestCustomAggregation.test_plot_custom_aggregation.0": [
-        "https://scitools.github.io/test-iris-imagehash/images/v4/fe816e81917e907eb43e873f85677ac190f0703c6a95811f1ac33ce1a57a6f18.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/fe816e81817e907eb43e873f85637ac198d8703c6a94811f1ac73ee1a57a6f90.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/ee816f81917e907eb03ec73f856f7ac198d070186e90811f1be33ee1a57a6e18.png"
     ],
     "gallery_tests.test_plot_custom_file_loading.TestCustomFileLoading.test_plot_custom_file_loading.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/faa0cbf1845e34be913787416edcc8bc3bc81f9b63332662a4ed30cdc1b2cd21.png",
@@ -107,9 +108,7 @@
         "https://scitools.github.io/test-iris-imagehash/images/v4/be817a87845ea56cec79817a919e338436a5c1e73fa16c736c4a3e816a1e6b1c.png"
     ],
     "gallery_tests.test_plot_polar_stereo.TestPolarStereo.test_plot_polar_stereo.0": [
-        "https://scitools.github.io/test-iris-imagehash/images/v4/e168317a92d36d89c5bb9e94c55e6f0c9a93c15a6ec584763b21716791de3a81.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/b9e16079971e9e93c8ce0f84c31e3b929f92c0ff3ca1c17e39e03961c07e3f80.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/ba1e615ec7e097a9961f9cb190f838e091c2c1e73f07c11f6f386b3cc1783e11.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/ba1e615ec7e097ad961f9cb190f038e091c2c1e73f07c11f6f386b3cc1793e01.png"
     ],
     "gallery_tests.test_plot_polynomial_fit.TestPolynomialFit.test_plot_polynomial_fit.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/abff4a9df26435886520c97f12414695c4b69d23934bc86adc969237d68ccc6f.png",
@@ -124,12 +123,7 @@
         "https://scitools.github.io/test-iris-imagehash/images/v4/fa854f19851a30e4cc76cd0bb0f932dca7c665b1c92ccb4b4ed19e9c3721b5c8.png"
     ],
     "gallery_tests.test_plot_projections_and_annotations.TestProjectionsAndAnnotations.test_plot_projections_and_annotations.1": [
-        "https://scitools.github.io/test-iris-imagehash/images/v4/e385699d9c3896627243318fcdad5a7dc6dba492e9b69964936dc21974b18592.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/e385699d9c3896727243318f8dad5a7dc65ba492b93699649b6dc25b64938592.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/e385699d9c3896627243318fcdad5a7dc6dba492b93699649b6dc25964938592.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/e3856b999c3896727243318f8dad5a75965ba492f9b69964db4cc65b64918592.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/e3856b999c3896727243318f8dad5a75865ba492e9b69964db6cc65b74918592.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/e3856d999c389662734731afcdad5a7384daa592b1b69b64d26dc29974b18590.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/e3856d999c389662734331afcd2d5a7184dba492b9b69b64d26dc29974b185b2.png"
     ],
     "gallery_tests.test_plot_rotated_pole_mapping.TestRotatedPoleMapping.test_plot_rotated_pole_mapping.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/fa15615e97a193adc15e1e81c4fa3eb49d30817e3e05c17e7ba59927817e1e01.png",
@@ -173,10 +167,11 @@
         "https://scitools.github.io/test-iris-imagehash/images/v4/e59661969e699659c0f719a6c967339a1992c07f3649c09c3f612669c07b3f66.png"
     ],
     "iris.tests.integration.plot.test_plot_2d_coords.Test.test_2d_coord_bounds_platecarree.0": [
-        "https://scitools.github.io/test-iris-imagehash/images/v4/ee816299954a1da699b6915ec25b6e419729c42c3f84bd9fe6d262d1d1dac076.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/ee816299954a1da699b6915ec25b6e419729c42c3f84bd9fe6d262d1d1dac076.png",
+        "https://scitools.github.io/test-iris-imagehash/images/v4/ee856299954a1da699b6915ec25b6e419729c42c3f84bd8fa7d262d1d1dac076.png"
     ],
     "iris.tests.integration.plot.test_plot_2d_coords.Test2dContour.test_2d_coords_contour.0": [
-        "https://scitools.github.io/test-iris-imagehash/images/v4/b4b0643ecb05cb43b0f23d90c53c4e1d3c5990eb1f83c1be2fb43cb4c47f3e41.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/b4b2643ecb05cb43b0f23d80c53c4e1d3e5990eb1f81c19f2f983cb1c4ff3e42.png"
     ],
     "iris.tests.integration.plot.test_vector_plots.TestQuiver.test_2d_plain_latlon.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/fb8d4f21c472b27e919d2e216f216b3178e69c7e961ab39a84696c616d245b94.png"
@@ -220,12 +215,14 @@
     "iris.tests.test_mapping.TestLimitedAreaCube.test_grid.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/bf80e2b1c17f1d0ac4f7c8d739a637202749699b6bb3ce3666e4b048944d9d89.png",
         "https://scitools.github.io/test-iris-imagehash/images/v4/bf80e2f1c17f1d0ac457c8d619a637213749699b6bb34e3666e4b04e944d9d89.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/ea05392995bac6d691ce3f21666569d86a96c6360ee195cb91e8ce54953b313b.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/ea05392995bac6d691ce3f21666569d86a96c6360ee195cb91e8ce54953b313b.png",
+        "https://scitools.github.io/test-iris-imagehash/images/v4/ea05392995bac6d691ea3f21666569d86a97c6320ee195cb91e8ce559539391b.png"
     ],
     "iris.tests.test_mapping.TestLimitedAreaCube.test_outline.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/fa81857e857e3e80857e7a817a817a817a81817f7a81857e857e857e857e7a81.png",
         "https://scitools.github.io/test-iris-imagehash/images/v4/fa81857e857e7e21857e7a817a817a857a81857a7a81857a857e857a857e7a84.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/fa1585e885e87a1785fa7a177a177e807a1585e85fa0857a85e86817857f6a16.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/fa1585e885e87a1785fa7a177a177e807a1585e85fa0857a85e86817857f6a16.png",
+        "https://scitools.github.io/test-iris-imagehash/images/v4/fa1585e885e86a1785fa7a177a177e807a1585e817a885ea85e86817857f7a17.png"
     ],
     "iris.tests.test_mapping.TestLimitedAreaCube.test_pcolormesh.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/bf81e6b1c17e1d4884bfc8df39a43720374969db69b34e26c4e4b0ca904f9d89.png",
@@ -234,7 +231,8 @@
     "iris.tests.test_mapping.TestLimitedAreaCube.test_scatter.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/ea053d2e916ac2d9c4d894346b24f3477acf68ad39329ed8c696e136c1ab9a71.png",
         "https://scitools.github.io/test-iris-imagehash/images/v4/ea053d2e916ac2d9c4d895346b2473477acf68ad39329ed8c69ee126c1ab9a71.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/ea05bd2e916ac2d984983d346b2473477acf69ad3d3296d8c696e126c1ab1e71.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/ea05bd2e916ac2d984983d346b2473477acf69ad3d3296d8c696e126c1ab1e71.png",
+        "https://scitools.github.io/test-iris-imagehash/images/v4/ea05bd3a91eac2d984983d346b2473477acf69ad1d3296d8c696e126c1ab1e71.png"
     ],
     "iris.tests.test_mapping.TestLowLevel.test_keywords.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/be21a71bc1de58e43a31871f7e856470c1fa9b8c7b81647384665b9ed1b998c1.png",
@@ -264,7 +262,8 @@
     "iris.tests.test_mapping.TestMappingSubRegion.test_simple.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/bd913e01d07ee07e926e87876f8196c1e0d36967393c1f181e2c3cb8b0f960d7.png",
         "https://scitools.github.io/test-iris-imagehash/images/v4/b9913d90c66eca6ec66ec2f3689195b6cf5b2f00392cb3496695621d34db6c92.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/b9913d90c66eca6ec66ec2f3689195b6cf5a2f003924b3496695e21db4db6c92.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/b9913d90c66eca6ec66ec2f3689195b6cf5a2f003924b3496695e21db4db6c92.png",
+        "https://scitools.github.io/test-iris-imagehash/images/v4/b9913d90c66eca6ec66ec2f3689195aecf5b2f00392cb3496495e21da4db6c92.png"
     ],
     "iris.tests.test_mapping.TestUnmappable.test_simple.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/fe818d6ac17e5a958d7ab12b9d677615986e666dc4f20dea7281d98833889b22.png",
@@ -281,7 +280,8 @@
     ],
     "iris.tests.test_plot.Test1dPlotMultiArgs.test_coord_coord_map.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/fbe0623dc9879d91b41e4b449b6579e78798a49b7872d2644b8c919b39306e6c.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/bbe0c21ccd179dc3b05e4b689b0771b48698961b7962da446e8ca5bb36716c6e.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/bbe0c21ccd179dc3b05e4b689b0771b48698961b7962da446e8ca5bb36716c6e.png",
+        "https://scitools.github.io/test-iris-imagehash/images/v4/bbe0c214cd979dc3b05e4b68db0771b48698961b7962d2446e8ca5bb36716c6e.png"
     ],
     "iris.tests.test_plot.Test1dPlotMultiArgs.test_coord_cube.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/8ff897066b41f076f81dce1fb007da79c50633e9c40626b8d1066df9d6067969.png",
@@ -315,7 +315,8 @@
     ],
     "iris.tests.test_plot.Test1dQuickplotPlotMultiArgs.test_coord_coord_map.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/fbe0623dc9879d91b41e4b449b6579e78798a49b7872d2644b8c919b39306e6c.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/bbe0c21ccd179dc3b05e4b689b0771b48698961b7962da446e8ca5bb36716c6e.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/bbe0c21ccd179dc3b05e4b689b0771b48698961b7962da446e8ca5bb36716c6e.png",
+        "https://scitools.github.io/test-iris-imagehash/images/v4/bbe0c214cd979dc3b05e4b68db0771b48698961b7962d2446e8ca5bb36716c6e.png"
     ],
     "iris.tests.test_plot.Test1dQuickplotPlotMultiArgs.test_coord_cube.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/87ffb5867f0060d4301f6d9fb007d899c50699e9c8668e78d8678d69de069969.png",
@@ -420,7 +421,8 @@
     "iris.tests.test_plot.TestContour.test_yx.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/fa56c3cc34e891b1c9a91c36c5a170e3c71b3e5993a784e492c49b4ecec76393.png",
         "https://scitools.github.io/test-iris-imagehash/images/v4/e85e36cb95b199999765cd3694b06478c7396329958434c2cecb6c6d69ce1b92.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/e85e36cb95a19999876d4d3694b06c78c7396329958434c2cecb6c6d69ce3b92.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/e85e36cb95a19999876d4d3694b06c78c7396329958434c2cecb6c6d69ce3b92.png",
+        "https://scitools.github.io/test-iris-imagehash/images/v4/e85e36cb95b199999e654d3694b26c78c7396329958434c2cacb6c6d69ce9392.png"
     ],
     "iris.tests.test_plot.TestContour.test_zx.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/8bfe857f7a01a56afa05854ad015bd00d015d50a90577e80857f7ea0857f7abf.png",
@@ -507,12 +509,10 @@
         "https://scitools.github.io/test-iris-imagehash/images/v4/fa816ac1857e853cc17f957ac15f3e849486c8f43e81c13b3f813e91c07e3f46.png"
     ],
     "iris.tests.test_plot.TestMissingCoord.test_no_u.0": [
-        "https://scitools.github.io/test-iris-imagehash/images/v4/fe816a95c17fb51e953e9485857a1f409552856a1f81c17e5ab94e15c0ff5a85.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/ea856a95955a954ac17f954ac07e3f48951ec07e3e81c0ff7ea16a81c0bf3e81.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/ea856a95955a954ac17f954a807e3f48951ac07e3e81c0ff7ea16a81c0ff3f81.png"
     ],
     "iris.tests.test_plot.TestMissingCoord.test_no_u.1": [
-        "https://scitools.github.io/test-iris-imagehash/images/v4/be0e695ac3f096b5943fd2a185fc1e8590e594ee1e05c17a4f403d0fe1fe4b42.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/ea956ab5954a954ac17f954a817e3f40950ac07f3e81c0ff7a856aa1c0ff3f80.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/ea956ab5954a954ac17e954a817f2f60950ac07f3e80c07f7a856aa5c2ff3f80.png"
     ],
     "iris.tests.test_plot.TestMissingCoord.test_no_v.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/fa8562b6c0773d09956a955a857a1d88845ec57e3f81c07e4ae56b21d0ff5a85.png",
@@ -700,7 +700,8 @@
         "https://scitools.github.io/test-iris-imagehash/images/v4/ebeaa5419e94b5019e97950d685395bee05361fad05560fad01570fef001dabe.png",
         "https://scitools.github.io/test-iris-imagehash/images/v4/ebeaa5419e95b5419e97950d6853953ee053617ad05560fad01570fef001dabe.png",
         "https://scitools.github.io/test-iris-imagehash/images/v4/ebfaa56f96a1856cd681a56ee8162d52e8467e12c50c7e8095ad7e0095ad03ff.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/eaa9b5699556854e9456854ed05625f9c0a92bfdc0a90afd81f97e00857e6af6.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/eaa9b5699556854e9456854ed05625f9c0a92bfdc0a90afd81f97e00857e6af6.png",
+        "https://scitools.github.io/test-iris-imagehash/images/v4/eaa9b5699556854e9456854ed05625f9d0a92bfdc0a90afd81f97e00855e7ab6.png"
     ],
     "iris.tests.test_plot.TestPlotCoordinatesGiven.test_tx.5": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/ebfaaf439e87b5019687b5019687b56ac05561fae07103fe6079687a607178f8.png",
@@ -736,7 +737,8 @@
     "iris.tests.test_plot.TestPlotCoordinatesGiven.test_yx.3": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/ea5649c434ac92e5d9c9361b95b39c38c3835a5ec6d966ced34c633099ace5a5.png",
         "https://scitools.github.io/test-iris-imagehash/images/v4/e85a6b6c96a597a591c9949b94b61b69c7926b5bccce66646b3869b831a52c26.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/e85e6b6c86a595a791c9349b94b71b69c7926b5bccca66646b1869b831a52ca6.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/e85e6b6c86a595a791c9349b94b71b69c7926b5bccca66646b1869b831a52ca6.png",
+        "https://scitools.github.io/test-iris-imagehash/images/v4/e85a6b6c86a595a791c9349b94b73b69c7926b5bccca66646b3869b031a52ca6.png"
     ],
     "iris.tests.test_plot.TestPlotCoordinatesGiven.test_yx.4": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/ad2f6d2dd2d09295c3c0c7d13c1bc6d23d2c696de0e53c3ac393daf6d205c2c4.png",
@@ -844,12 +846,10 @@
         "https://scitools.github.io/test-iris-imagehash/images/v4/a3ffc1d87e00b49964179d28f16bce4b98724b268c6d58e1972e4874998b2e7e.png"
     ],
     "iris.tests.test_plot.TestSimple.test_bounds.0": [
-        "https://scitools.github.io/test-iris-imagehash/images/v4/fa9562fcc7c0b50bb53b9f8085727a157a95c0f67a85e07e0be08069e07d9fa0.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/ea856a85954a957ac17e954ac17a9c3e956ac07e3e81c07f3e857aa5c2753f80.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/ea856a85954a957ac17e954ac17a9c3e956ac07e3e80c07f3e857aa5c27d3f80.png"
     ],
     "iris.tests.test_plot.TestSimple.test_points.0": [
-        "https://scitools.github.io/test-iris-imagehash/images/v4/fa8562b7c2763d09956a955a855a1d88d45ec57a3f81c07e6ae16b21c0ff7a81.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/ea856a85957a957ac17e954ac17e1ca2954ac07e3e81c07f3e807a85c1ff3f81.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/fa856a85957a957ac17e954ac17e1ca2950bc07e3e80c07f3e807a85c1ff3f81.png"
     ],
     "iris.tests.test_plot.TestSymbols.test_cloud_cover.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/e95a330c96a5ccf2695a330c96a5ccf2695a330c96b5ccf3694a330c96b5ccf3.png",
@@ -891,12 +891,14 @@
     "iris.tests.test_quickplot.TestLabels.test_map.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/ea5e618434ac36e5c1c9369b95b39c38c3a39a4fcee19a6e9b64cb609925cd25.png",
         "https://scitools.github.io/test-iris-imagehash/images/v4/e85a636c86a597a593c9b49b94b79969c396c95bccc69a64db30d9b039a52c26.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/e85a636c86a597a791c9349b94b79969c396c95bccc69a64db38c9b039a58ca6.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/e85a636c86a597a791c9349b94b79969c396c95bccc69a64db38c9b039a58ca6.png",
+        "https://scitools.github.io/test-iris-imagehash/images/v4/e85a634c86a597a793c9349b94b79969c396c95bcce69a64d938c9b039a58ca6.png"
     ],
     "iris.tests.test_quickplot.TestLabels.test_map.1": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/ea5e618434ac36e5c1c9369b95b39c38c3a39a4ecef19a6e9b64cb609925cd25.png",
         "https://scitools.github.io/test-iris-imagehash/images/v4/e85a636c86a597a593c9b49b94b79969c396c95bccc69a64db30d9b039a52c26.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/e85a636c86a597a791c9349b94b79969c396c95bccc69a64db38c9b039a58ca6.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/e85a636c86a597a791c9349b94b79969c396c95bccc69a64db38c9b039a58ca6.png",
+        "https://scitools.github.io/test-iris-imagehash/images/v4/e85a636c86a597a793c9349b94b69969c396c95bcce69a64d938c9b039a58ca6.png"
     ],
     "iris.tests.test_quickplot.TestLabels.test_pcolor.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/bb423d4e94a5c6b9c15adaadc1fb6a469c8de43a3e07904e5f016b57984e1ea1.png",
@@ -911,37 +913,22 @@
         "https://scitools.github.io/test-iris-imagehash/images/v4/fe816a85857a957ac07f957ac07f3e80956ac07f3e80c07f3e813e85c07e3f80.png"
     ],
     "iris.tests.test_quickplot.TestQuickplotCoordinatesGiven.test_tx.0": [
-        "https://scitools.github.io/test-iris-imagehash/images/v4/fa856a95e15ab51a953e9485857a1f409552857e1fc1c07e5abd4a35e07f4aa5.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/ea856a95955a956ac17f950ac07e3f48951ac07f3f81c0ff3ea16aa1c0be3e81.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/ea856a95955a956ac17f950a807e3f4c951ac07e3f81c0ff3ea16aa1c0bd3f81.png"
     ],
     "iris.tests.test_quickplot.TestQuickplotCoordinatesGiven.test_tx.1": [
-        "https://scitools.github.io/test-iris-imagehash/images/v4/fa8562b7c2763d09956a955a855a1d88d45ec57a3f81c07e6ae16b21c0ff7a81.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/ea856a85957a957ac17e954ac17e1ca2954ac07e3e81c07f3e807a85c1ff3f81.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/fa856a85957a957ac17e954ac17e1ca2950bc07e3e80c07f3e807a85c1ff3f81.png"
     ],
     "iris.tests.test_quickplot.TestQuickplotCoordinatesGiven.test_tx.2": [
-        "https://scitools.github.io/test-iris-imagehash/images/v4/8aff878b7f00953062179561f087953ad167997a80784a7fc1e5d86d9978485f.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/8aff878b7f80953860179561f087953ad167997a80784a7fc1e5d86d9978485b.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/eafdc6c9f720953030968d6795d28d6a95674b7b81304aedc9e51cad8d186c9a.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/eafdc6c9f720943030968d67d5d28d6e95674b7b81304aedc9651cad8d186c9a.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/eafdeec9f729943032168d66d4cb896e9567497b81304aedc96514ad8d18669a.png"
     ],
     "iris.tests.test_quickplot.TestQuickplotCoordinatesGiven.test_tx.3": [
-        "https://scitools.github.io/test-iris-imagehash/images/v4/82ff8db67f94952e76159d6bb01dcd629059c962c1fbd9c1c062da74d820ca74.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/82be8db67f95952e761d9d6bb01dcd628059c962c1fbd9e1c072da64d060ca74.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/82fe8db67f95952e76159d6bb01dcd629059c962c1fbd9e1c072da64d020ca74.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/a2ff6a967f00952eb40d9d0f900fcd62c47069f3d1f93a909c266e34d8a56f68.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/a2ff4b967f00950eb40d9d0f900fcd62d470e9f2c1f93a909c266e34d8a56f6c.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/a6fb4b967f00950eb00f9d0f900fcd62dc7868f2c1bb3a909c266e34daa52f6c.png"
     ],
     "iris.tests.test_quickplot.TestQuickplotCoordinatesGiven.test_tx.4": [
-        "https://scitools.github.io/test-iris-imagehash/images/v4/aa97b70ff5f0970f20b2956a6a17957af805da71d06f5a75d02cd870d800d8f2.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/e1faa549de9497090697971d60539f3ef171c87ac075487ad025d87ed801da3e.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/eadab54fd7a1856d90819d6df8169962e946d862802ed8809ded7e809d2d03ff.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/eaa9b549f756854ea0169d6ad5568969d9a909ed80290afdd9e97e008d6e6a96.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/eaa9b549f756854ea0168d6ed556896dd8e909ed88290afdd9e97e008d6e2296.png"
     ],
     "iris.tests.test_quickplot.TestQuickplotCoordinatesGiven.test_tx.5": [
-        "https://scitools.github.io/test-iris-imagehash/images/v4/e8faad47f784bd0596859d03969f9962c05dc96ee07189fe6870c862687178f8.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/a8fa2d4797859585b6959d07605f896ee051697ad061d9fad0619aaed801deae.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/aa5b3c0c978187a4b60199bc605f6976687e6873d07c99e390acdc0391fc2f7b.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/aad73e0df78085acb50195ac8029d9f2d16cd8f2d1ec48f280ec6a536a17b7f3.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/aad73e0df78085ac840395ac9428d9fad56cd8f2906c48f2d0ec7a536a1737f3.png"
     ],
     "iris.tests.test_quickplot.TestQuickplotCoordinatesGiven.test_x.0": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/a6ffb5097e84cde2224598d1649f8d6cd2388c76d0799867d009da76c9f8d866.png",
@@ -972,7 +959,8 @@
     "iris.tests.test_quickplot.TestQuickplotCoordinatesGiven.test_yx.3": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/ea5e618434ac36e5c1c9369b95b39c38c3a39a4fcee19a6e9b64cb609925cd25.png",
         "https://scitools.github.io/test-iris-imagehash/images/v4/e85a636c86a597a593c9b49b94b79969c396c95bccc69a64db30d9b039a52c26.png",
-        "https://scitools.github.io/test-iris-imagehash/images/v4/e85a636c86a597a791c9349b94b79969c396c95bccc69a64db38c9b039a58ca6.png"
+        "https://scitools.github.io/test-iris-imagehash/images/v4/e85a636c86a597a791c9349b94b79969c396c95bccc69a64db38c9b039a58ca6.png",
+        "https://scitools.github.io/test-iris-imagehash/images/v4/e85a634c86a597a793c9349b94b79969c396c95bcce69a64d938c9b039a58ca6.png"
     ],
     "iris.tests.test_quickplot.TestQuickplotCoordinatesGiven.test_yx.4": [
         "https://scitools.github.io/test-iris-imagehash/images/v4/ad2f6d2fd2d09295c2d1c3d33c1bc2d67d2c696ce0653c3ac2b1d976da05c2c4.png",
@@ -1034,4 +1022,4 @@
         "https://scitools.github.io/test-iris-imagehash/images/v4/82fe81987fdf77ffe0002addd4002805dd28df67d9a9d4625bfddc209841de20.png",
         "https://scitools.github.io/test-iris-imagehash/images/v4/82fa80997f547799a0037a00d52f0956ddaf9f7e98a1816e09f5d8260bfffe00.png"
     ]
-}
\ No newline at end of file
+}
diff --git a/lib/iris/tests/results/unit/analysis/cartography/project/TestAll/cube.cml b/lib/iris/tests/results/unit/analysis/cartography/project/TestAll/cube.cml
index 6c192a1006..5504f2a91f 100644
--- a/lib/iris/tests/results/unit/analysis/cartography/project/TestAll/cube.cml
+++ b/lib/iris/tests/results/unit/analysis/cartography/project/TestAll/cube.cml
@@ -9,24 +9,21 @@
         <dimCoord id="1d45e087" points="[0.0]" shape="(1,)" standard_name="forecast_period" units="Unit('hours')" value_type="float64"/>
       </coord>
       <coord datadims="[2, 3]">
-        <auxCoord id="8f75dad5" points="[[-29.5486755686, -23.2425386265, -27.1960399432,
-		 ..., -26.4183339764, -23.4102889086,
-		 -30.5598035506],
-		[-5.31277829259, -7.60878083145, -22.525325091,
-		 ..., -20.3389138774, -6.63677815264,
-		 -5.96000876128],
-		[11.9373940243, 1.68737606823, -19.7510874124,
-		 ..., -16.5990757719, 3.75281211255,
-		 12.1482277251],
+        <auxCoord id="8f75dad5" points="[[inf, inf, -27.1960378264, ..., -26.4183314681,
+		 inf, inf],
+		[inf, -7.60877872467, -22.5253246282, ...,
+		 -20.3389131851, -6.6367758118, inf],
+		[11.9373960713, 1.68737720645, -19.7510869281,
+		 ..., -16.5990751865, 3.75281337984,
+		 12.1482298878],
 		..., 
-		[84.2615074996, 54.8444519294, 26.7572399859,
-		 ..., 30.1637441878, 58.6051869919,
-		 86.9541960184],
-		[68.173538568, 62.6851805113, 39.6290904051,
-		 ..., 42.324932868, 64.8680482789, 66.5017981217],
-		[43.3491677352, 51.7189413318, 46.2669886567,
-		 ..., 47.2804916021, 51.4709777887,
-		 42.1572752986]]" shape="(10, 10)" standard_name="latitude" units="Unit('degrees')" value_type="float64">
+		[84.2615071705, 54.8444503701, 26.7572382165,
+		 ..., 30.1637424823, 58.6051855118,
+		 86.9541974993],
+		[inf, 62.6851802716, 39.629088106, ...,
+		 42.3249307728, 64.8680485778, inf],
+		[inf, inf, 46.2669891845, ..., 47.2804926757,
+		 inf, inf]]" shape="(10, 10)" standard_name="latitude" units="Unit('degrees')" value_type="float64">
           <rotatedGeogCS ellipsoid="GeogCS(6371229.0)" grid_north_pole_latitude="37.5" grid_north_pole_longitude="177.5"/>
         </auxCoord>
       </coord>
@@ -40,23 +37,20 @@
         </dimCoord>
       </coord>
       <coord datadims="[2, 3]">
-        <auxCoord id="81715b9b" points="[[165.651442753, 178.244991596, -168.158926231,
-		 ..., 169.237783452, -176.909512275,
-		 -164.826658657],
-		[171.94140771, -164.537718135, -145.687720691,
-		 ..., 147.432981219, 167.102019536,
-		 -169.282739452],
-		[-175.009064548, -147.024893924, -126.259032068,
-		 ..., 128.51309535, 150.23087257, 178.899398957],
+        <auxCoord id="81715b9b" points="[[inf, inf, -168.158920348, ..., 169.237777806,
+		 inf, inf],
+		[inf, -164.537714569, -145.687716669, ...,
+		 147.432977295, 167.102016129, inf],
+		[-175.009062798, -147.024891707, -126.259029624,
+		 ..., 128.513092975, 150.23087042, 178.899397359],
 		..., 
-		[-58.3498044086, -70.8813751857, -58.2031018979,
-		 ..., 60.1459626823, 72.0019743312, 20.695582309],
-		[22.0508714127, -35.1608425218, -42.536925264,
-		 ..., 43.0527802786, 31.4703414616,
-		 -27.6376083083],
-		[17.2456810934, 2.60343563417, -15.3083834763,
-		 ..., 14.270914103, -4.55555121054,
-		 -17.7002310265]]" shape="(10, 10)" standard_name="longitude" units="Unit('degrees')" value_type="float64">
+		[-58.34983089, -70.8813785605, -58.2031036304,
+		 ..., 60.1459645527, 72.0019781785,
+		 20.6956240803],
+		[inf, -35.1608514733, -42.5369291003, ...,
+		 43.052784475, 31.4703511243, inf],
+		[inf, inf, -15.3083916055, ..., 14.2709222711,
+		 inf, inf]]" shape="(10, 10)" standard_name="longitude" units="Unit('degrees')" value_type="float64">
           <rotatedGeogCS ellipsoid="GeogCS(6371229.0)" grid_north_pole_latitude="37.5" grid_north_pole_longitude="177.5"/>
         </auxCoord>
       </coord>
@@ -74,10 +68,10 @@
 		15305249.9975]" shape="(10,)" standard_name="projection_x_coordinate" units="Unit('m')" value_type="float64"/>
       </coord>
       <coord datadims="[2]">
-        <dimCoord id="3589f6ce" points="[-7762639.61572, -6037608.59, -4312577.56429,
-		-2587546.53857, -862515.512857, 862515.512857,
-		2587546.53857, 4312577.56429, 6037608.59,
-		7762639.61572]" shape="(10,)" standard_name="projection_y_coordinate" units="Unit('m')" value_type="float64"/>
+        <dimCoord id="3589f6ce" points="[-7762639.19859, -6037608.26557, -4312577.33255,
+		-2587546.39953, -862515.46651, 862515.46651,
+		2587546.39953, 4312577.33255, 6037608.26557,
+		7762639.19859]" shape="(10,)" standard_name="projection_y_coordinate" units="Unit('m')" value_type="float64"/>
       </coord>
       <coord datadims="[1]">
         <auxCoord bounds="[[1.0, 0.998464],
diff --git a/lib/iris/tests/test_mapping.py b/lib/iris/tests/test_mapping.py
index d7cc553116..70345b50ee 100644
--- a/lib/iris/tests/test_mapping.py
+++ b/lib/iris/tests/test_mapping.py
@@ -116,26 +116,26 @@ def test_simple(self):
         plt.subplot(221)
         plt.title("Default")
         iplt.contourf(self.cube)
-        plt.gca().coastlines()
+        plt.gca().coastlines("110m")
 
         # Second sub-plot
         plt.subplot(222, projection=ccrs.Mollweide(central_longitude=120))
         plt.title("Molleweide")
         iplt.contourf(self.cube)
-        plt.gca().coastlines()
+        plt.gca().coastlines("110m")
 
         # Third sub-plot (the projection part is redundant, but a useful
         # test none-the-less)
         ax = plt.subplot(223, projection=iplt.default_projection(self.cube))
         plt.title("Native")
         iplt.contour(self.cube)
-        ax.coastlines()
+        ax.coastlines("110m")
 
         # Fourth sub-plot
         ax = plt.subplot(2, 2, 4, projection=ccrs.PlateCarree())
         plt.title("PlateCarree")
         iplt.contourf(self.cube)
-        ax.coastlines()
+        ax.coastlines("110m")
 
         self.check_graphic()
 
@@ -250,7 +250,7 @@ def test_outline(self):
 
     def test_scatter(self):
         iplt.points(self.cube)
-        plt.gca().coastlines()
+        plt.gca().coastlines("110m")
         self.check_graphic()
 
 
diff --git a/lib/iris/tests/test_plot.py b/lib/iris/tests/test_plot.py
index 04418d8d40..e5c8269049 100644
--- a/lib/iris/tests/test_plot.py
+++ b/lib/iris/tests/test_plot.py
@@ -83,7 +83,7 @@ def test_missing_cs(self):
         cube.coord("latitude").coord_system = None
         cube.coord("longitude").coord_system = None
         qplt.contourf(cube)
-        qplt.plt.gca().coastlines()
+        qplt.plt.gca().coastlines("110m")
         self.check_graphic()
 
 
@@ -187,7 +187,7 @@ def test_coord_coord_map(self):
             units="degrees_north",
         )
         self.draw_method(lon, lat)
-        plt.gca().coastlines()
+        plt.gca().coastlines("110m")
         self.check_graphic()
 
     def test_cube_cube(self):
@@ -262,7 +262,7 @@ def test_coord_coord_map(self):
         y = self.cube.coord("latitude")
         c = self.cube.data
         self.draw_method(x, y, c=c, edgecolor="none")
-        plt.gca().coastlines()
+        plt.gca().coastlines("110m")
         self.check_graphic()
 
     def test_coord_cube(self):
@@ -891,7 +891,7 @@ def setUp(self):
 
     def test_default(self):
         iplt.contourf(self.cube)
-        plt.gca().coastlines()
+        plt.gca().coastlines("110m")
         self.check_graphic()
 
     def test_coords(self):
@@ -899,23 +899,23 @@ def test_coords(self):
         rlat = self.cube.coord("grid_latitude")
         rlon = self.cube.coord("grid_longitude")
         iplt.contourf(self.cube, coords=[rlon, rlat])
-        plt.gca().coastlines()
+        plt.gca().coastlines("110m")
         self.check_graphic()
         # Pass in auxiliary coords.
         lat = self.cube.coord("latitude")
         lon = self.cube.coord("longitude")
         iplt.contourf(self.cube, coords=[lon, lat])
-        plt.gca().coastlines()
+        plt.gca().coastlines("110m")
         self.check_graphic()
 
     def test_coord_names(self):
         # Pass in names of dimension coords.
         iplt.contourf(self.cube, coords=["grid_longitude", "grid_latitude"])
-        plt.gca().coastlines()
+        plt.gca().coastlines("110m")
         self.check_graphic()
         # Pass in names of auxiliary coords.
         iplt.contourf(self.cube, coords=["longitude", "latitude"])
-        plt.gca().coastlines()
+        plt.gca().coastlines("110m")
         self.check_graphic()
 
     def test_yx_order(self):
@@ -992,7 +992,7 @@ def test_plot_tmerc(self):
         )
         self.cube = iris.load_cube(filename)
         iplt.pcolormesh(self.cube[0])
-        plt.gca().coastlines()
+        plt.gca().coastlines("110m")
         self.check_graphic()
 
 
diff --git a/lib/iris/tests/unit/analysis/cartography/test_project.py b/lib/iris/tests/unit/analysis/cartography/test_project.py
index 33edfb5675..ce6c2151d8 100644
--- a/lib/iris/tests/unit/analysis/cartography/test_project.py
+++ b/lib/iris/tests/unit/analysis/cartography/test_project.py
@@ -142,8 +142,8 @@ def test_extent(self):
             [
                 -17005833.33052523,
                 17005833.33052523,
-                -8625155.12857459,
-                8625155.12857459,
+                -8625154.6651,
+                8625154.6651,
             ],
         )
 
diff --git a/lib/iris/tests/unit/experimental/raster/test_export_geotiff.py b/lib/iris/tests/unit/experimental/raster/test_export_geotiff.py
index 487209243f..2a5b7b3572 100644
--- a/lib/iris/tests/unit/experimental/raster/test_export_geotiff.py
+++ b/lib/iris/tests/unit/experimental/raster/test_export_geotiff.py
@@ -124,9 +124,10 @@ def test_sphere(self):
             # String has embedded floating point values,
             # Test with values to N decimal places, using a regular expression.
             re_pattern = (
-                r'GEOGCS\["unnamed ellipse",DATUM\["unknown",'
-                r'SPHEROID\["unnamed",637....,0\]\],PRIMEM\["Greenwich",0\],'
-                r'UNIT\["degree",0.01745[0-9]*\]\]'
+                r'GEOGCS\["unknown",DATUM\["unknown",'
+                r'SPHEROID\["unknown",637....,0\]\],PRIMEM\["Greenwich",0\],'
+                r'UNIT\["degree",0.01745[0-9]*,AUTHORITY\["EPSG","9122"\]\],'
+                r'AXIS\["Latitude",NORTH\],AXIS\["Longitude",EAST\]\]'
             )
             re_exp = re.compile(re_pattern)
             self.assertIsNotNone(
@@ -145,9 +146,11 @@ def test_ellipsoid(self):
             # String has embedded floating point values,
             # Test with values to N decimal places, using a regular expression.
             re_pattern = (
-                r'GEOGCS\["unnamed ellipse",DATUM\["unknown",'
-                r'SPHEROID\["unnamed",637....,375.117[0-9]*\]\],'
-                r'PRIMEM\["Greenwich",0\],UNIT\["degree",0.01745[0-9]*\]\]'
+                r'GEOGCS\["unknown",DATUM\["unknown",'
+                r'SPHEROID\["unknown",637....,375.117[0-9]*\]\],'
+                r'PRIMEM\["Greenwich",0\],UNIT\["degree",0.01745[0-9]*,'
+                r'AUTHORITY\["EPSG","9122"\]\],AXIS\["Latitude",NORTH\],'
+                r'AXIS\["Longitude",EAST\]\]'
             )
             re_exp = re.compile(re_pattern)
             self.assertIsNotNone(
diff --git a/requirements/core.txt b/requirements/core.txt
index dbc0333d7c..9cedc72680 100644
--- a/requirements/core.txt
+++ b/requirements/core.txt
@@ -3,12 +3,11 @@
 
 # Without these, iris won't even import.
 
-cartopy>=0.12
-#conda: proj4<6
+cartopy>=0.18
 cf-units>=2
 cftime
 dask[array]>=2  #conda: dask>=2
-matplotlib<3.3
+matplotlib
 netcdf4
 numpy>=1.14
 scipy
diff --git a/requirements/extensions.txt b/requirements/extensions.txt
index 8e8e847f88..220fb562ec 100644
--- a/requirements/extensions.txt
+++ b/requirements/extensions.txt
@@ -6,4 +6,3 @@
 # first.
 
 iris-grib  #conda:
-gdal