visualizing trade flow in Python maps Part I

gistfile1.txt

ax = plt.axes(projection=ccrs.PlateCarree())

# get country centroids
ax.set_extent([lon[0] - 1, lon[1] + 1, lat[0] - 1, lat[1] + 1])

for key, cn in zip(c.keys(),c.values()):
    ax.add_geometries(cn.geometry,
                      crs=ccrs.PlateCarree(),
                      edgecolor="grey",
                      facecolor="whitesmoke",
                     zorder = 1)
    
    # Add country names
    centroid = cn.geometry.centroid
    
    ax.text(
        centroid.x,
        centroid.y,
        key,  # Assuming 'name' is the attribute containing the country names
        horizontalalignment='center',
        verticalalignment='center',
        transform=ccrs.PlateCarree(),
        fontsize=8,  # Adjust the font size as needed
        color='black',  # Set the color of the text
        zorder = 2
       )
    

# set up a colormap
cmap = colormaps.get("viridis_r")
tmin = np.array([v for v in transfers.values()]).min()
tmax = np.array([v for v in transfers.values()]).max()
norm = Normalize(tmin, tmax)

for tr in transfers:
    c1, c2 = tr.split(",")
    startarrow1 = startarrow1_dict[tr]
    endarrow1 = endarrow1_dict[tr]
    
    startarrow2 = startarrow2_dict[tr]
    endarrow2 = endarrow2_dict[tr]
    
    
    t1 = transfers[tr][0]
    col = cmap(norm(t1))
    
    # Use the arrow function to draw arrows
    arrow = mpatches.FancyArrowPatch(
        (startarrow1[0], startarrow1[1]),
        (endarrow1[0], endarrow1[1]),
        mutation_scale=20,    #control the length of head of arrow 
        color=col,
        arrowstyle='-|>',
        linewidth=2,  # You can adjust the linewidth to control the arrow body width
        zorder = 3
    )
    ax.add_patch(arrow)
    
    #OTHER WAY
    offset = 1
    t2 = transfers[tr][1]
    col = cmap(norm(t2))
    arrow = mpatches.FancyArrowPatch(
        (startarrow2[0], startarrow2[1]),
        (endarrow2[0], endarrow2[1]),
        mutation_scale=20,
        color=col,
        arrowstyle='-|>',
        linewidth=2,  # You can adjust the linewidth to control the arrow body width
        zorder = 4
    )
    ax.add_patch(arrow)
    
sm = ScalarMappable(norm, cmap)
fig = plt.gcf()
cbar = fig.colorbar(sm, ax=ax,
            orientation = "horizontal",
            pad = 0.05,  #distance between main plot and colorbar
            shrink = 0.8, #control length
            aspect = 20  #control width
            )
cbar.set_label("Trade flow")

plt.title("Trade flow in South Asia")
plt.axis("off")
plt.savefig("trade_flow2_with_labels.jpeg",
           dpi = 300)
plt.show()