[BUGFIX] Fix wind rose plots (#930)

floris/wind_data.py

@@ -610,7 +610,11 @@ def plot(
 
         # Get the wd_step
         if wd_step is None:
-            wd_step = wd_bins[1] - wd_bins[0]
+            if len(wd_bins) >= 2:
+                wd_step = wd_bins[1] - wd_bins[0]
+            else:
+                # This admittedly an odd edge case
+                wd_step = 360.0
 
         # Get a color array
         color_array = plt.get_cmap(color_map, len(ws_bins))
@@ -619,7 +623,7 @@ def plot(
             rects = []
             freq_table_sub = freq_table[wd_idx, :].flatten()
             for ws_idx, ws in reversed(list(enumerate(ws_bins))):
-                plot_val = freq_table_sub[:ws_idx].sum()
+                plot_val = freq_table_sub[:ws_idx + 1].sum()
                 rects.append(
                     ax.bar(
                         np.radians(wd),
@@ -1453,7 +1457,7 @@ def plot(
         color_map="viridis_r",
         wd_step=15.0,
         wind_rose_var_step=None,
-        legend_kwargs={},
+        legend_kwargs={"title": "Wind speed [m/s]"},
     ):
         """
         This method creates a wind rose plot showing the frequency of occurrence
@@ -1480,7 +1484,7 @@ def plot(
                 will be used if wind_rose_var = "ws", and a value of 4% will be
                 used if wind_rose_var = "ti".
             legend_kwargs (dict, optional): Keyword arguments to be passed to
-                ax.legend().
+                ax.legend(). Defaults to {"title": "Wind speed [m/s]"}.
 
         Returns:
             :py:class:`matplotlib.pyplot.axes`: A figure axes object containing
@@ -1519,7 +1523,7 @@ def plot(
             rects = []
             freq_table_sub = freq_table[wd_idx, :].flatten()
             for var_idx, ws in reversed(list(enumerate(var_bins))):
-                plot_val = freq_table_sub[:var_idx].sum()
+                plot_val = freq_table_sub[:var_idx + 1].sum()
                 rects.append(
                     ax.bar(
                         np.radians(wd),