Fix scatter norm keyword

doc/source/whatsnew/v1.5.0.rst

@@ -421,7 +421,7 @@ Plotting
 - Bug in :meth:`DataFrame.plot.box` that prevented labeling the x-axis (:issue:`45463`)
 - Bug in :meth:`DataFrame.boxplot` that prevented passing in ``xlabel`` and ``ylabel`` (:issue:`45463`)
 - Bug in :meth:`DataFrame.boxplot` that prevented specifying ``vert=False`` (:issue:`36918`)
--
+- Bug in :meth:`DataFrame.scatter` that prevented specifying ``norm`` (:issue:`45809`)
 
 Groupby/resample/rolling
 ^^^^^^^^^^^^^^^^^^^^^^^^

pandas/plotting/_matplotlib/core.py

@@ -1082,7 +1082,7 @@ def _make_plot(self):
             bounds = np.linspace(0, n_cats, n_cats + 1)
             norm = colors.BoundaryNorm(bounds, cmap.N)
         else:
-            norm = None
+            norm = self.kwds.pop("norm", None)
         # plot colorbar if
         # 1. colormap is assigned, and
         # 2.`c` is a column containing only numeric values

pandas/tests/plotting/frame/test_frame.py

@@ -787,6 +787,27 @@ def test_plot_scatter_with_s(self):
         ax = df.plot.scatter(x="a", y="b", s="c")
         tm.assert_numpy_array_equal(df["c"].values, right=ax.collections[0].get_sizes())
 
+    def test_plot_scatter_with_norm(self):
+        # added while fixing GH 45809
+        import matplotlib as mpl
+
+        df = DataFrame(np.random.random((10, 3)) * 100, columns=["a", "b", "c"])
+        norm = mpl.colors.LogNorm()
+        ax = df.plot.scatter(x="a", y="b", c="c", norm=norm)
+        assert ax.collections[0].norm is norm
+
+    def test_plot_scatter_without_norm(self):
+        # added while fixing GH 45809
+        import matplotlib as mpl
+
+        df = DataFrame(np.random.random((10, 3)) * 100, columns=["a", "b", "c"])
+        ax = df.plot.scatter(x="a", y="b", c="c")
+        plot_norm = ax.collections[0].norm
+        color_min_max = (df.c.min(), df.c.max())
+        default_norm = mpl.colors.Normalize(*color_min_max)
+        for value in df.c:
+            assert plot_norm(value) == default_norm(value)
+
     @pytest.mark.slow
     def test_plot_bar(self):
         df = DataFrame(