I'm creating a plot using Matplotlib. I want the legend keys (the shapes next to the descriptive text in the legend) to be arrows similar to the ones present in the figure. I've been able to get an output that is close to what I want as you can see in the picture below. There are arrows in the legend but they are incredibly long and narrow. The current iteration of my plot. The legend key arrows are present but tiny. The code I used to create the plot is here: # Define custom legend handler class ArrowHandler(HandlerBase): def create_artists(self, legend, orig_handle, xdescent, ydescent, width, height, fontsize, trans): arrow = FancyArrowPatch((0, 5), (40, 5), arrowstyle='->', color=orig_handle.get_edgecolor(), mutation_aspect=20) return [arrow] # Plot the river profile using Matplotlib plt.figure(figsize=(11, 6)) plt.plot(creek_long_profile_dataframes['Foley Creek']['distance_upstream_km'], creek_long_profile_dataframes['Foley Creek']['elevation_m'], color='#368bb5', linewidth=2) ### Add sediment delivery points as colored arrows delivery_data = creek_sed_delivery_dataframes["Foley Creek"] # Get range of x and y values to be able to standardize the size of the arrows x_min_max = creek_long_profile_dataframes['Foley Creek']['distance_upstream_km'].agg(['min', 'max']) x_range = x_min_max[1] - x_min_max[0] y_min_max = creek_long_profile_dataframes['Foley Creek']['elevation_m'].agg(['min', 'max']) y_range = y_min_max[1] - y_min_max[0] # Add arrows to the figure for index, row in delivery_data.iterrows(): x = row['distance_upstream_km'] y = row['elevation_m'] color = '#1b9e77' if row['mass_movement_type'] == 'Debris Flow' else '#7570b3' plt.arrow(x, y+(0.098*y_range), 0, -(0.088*y_range), width=0.006*x_range, head_width=0.015*x_range, head_length=0.029*y_range, color=color, length_includes_head=True) ### done adding sediment delivery arrows # Set axis labels plt.xlabel('Distance upstream (km)') plt.ylabel('Elevation (m)') # Set title plt.title('Sediment Delivery Along Foley Creek') # Add grid plt.grid(which='major', axis='both') # Define the legend elements legend_elements = [ FancyArrowPatch((0, 0), (0, 0), arrowstyle='->', color='#1b9e77', label='Debris Flow'), FancyArrowPatch((0, 0), (0, 0), arrowstyle='->', color='#7570b3', label='Debris Avalanche') ] # Create the legend with custom handler plt.legend(handles=legend_elements, handler_map={FancyArrowPatch: ArrowHandler()}) # Save figure # plt.savefig('sed_delivery_figs/sed_delivery_foley.pdf', dpi=300, bbox_inches='tight') # Show the plot plt.show() I first tried passing a list of Arrow instances similar to the code below. # Define the legend elements legend_elements = [ FancyArrowPatch((0, 0), (0.5, 0), arrowstyle='->', color='#1b9e77', label='Debris Flow'), FancyArrowPatch((0, 0), (0.5, 0), arrowstyle='->', color='#7570b3', label='Debris Avalanche') ] # Add the legend plt(handles=legend_elements, loc='center') This resulted in legend keys which were rectangles (not the arrows I'm hoping for) but which were the correct color. I hobbled together some code to create a custom legend handler but I unfortunately have very little understanding of how they work and how I should be defining it. Any help would be appreciated. I've taken a look at some related posts (here and here) but I haven't been able to implement their suggestions in my use case because I'm having trouble wrapping my head around some aspects of Matplotlib. Does anyone know how I can put arrows in the legend like the ones that I plotted in the figure itself? Is there a simpler approach? Continue reading...
