Polish nez levels.

pymagglobal/_commands.py

@@ -530,18 +530,24 @@ def maps(args, fig=None):
             units[1] = r'deg.'
         else:
             field /= 1000
+            vmax = np.ceil(np.max(np.abs(field), axis=1))
 
-        cbar_hght = 0.06
+            for it in range(3):
+                levels[it] = np.linspace(-vmax[it], vmax[it], 11)
+
+        cbar_hght = 0.08
         if fig is None:
             proj = ccrs.Mollweide()
-            fig, axs = plt.subplots(1, 3, figsize=(13, 3),
+            fig, axs = plt.subplots(1, 3, figsize=(13, 3.4),
                                     subplot_kw={'projection': proj})
+            fig.tight_layout()
+            fig.subplots_adjust(top=0.8, bottom=0.25, wspace=0.1)
             colaxs = []
             for it in range(3):
                 bnds = axs[it].get_position().bounds
 
                 colaxs.append(fig.add_axes([bnds[0],
-                                            bnds[1]-0.1-cbar_hght,
+                                            bnds[1]-0.06-cbar_hght,
                                             bnds[2],
                                             cbar_hght]))
             cbar_orientation = 'horizontal'