Python Matplotlib Basemap overlay small image on map plot

Question

I am plotting data from an aircraft on a map and I would like to insert this 75px by 29px PNG image of an airplane at the coordinates of the latest data point on the plot.

Answer 1

With basemap, you can generally just use normal pyplot style commands if you translate your coordinates using the map instance first. In this case, you can just transform the extent into uv coordinates with:

x0, y0 = m(x[-1], y[-1])
x1, y1 = m(x[-1] + 0.5, y[-1] + 0.5)

And then subsequently you will be able to do:

im = plt.imshow(img, extent=(x0, x1, y0, y1))

My full solution to this looks like:

import matplotlib.pyplot as plt
from mpl_toolkits.basemap import Basemap
import numpy as np


lats = np.arange(26, 29, 0.5)
lons = np.arange(-90, -87, 0.5)

m = Basemap(projection='cyl', llcrnrlon=min(lons)-2, llcrnrlat=min(lats)-2,
            urcrnrlon=max(lons)+2, urcrnrlat=max(lats)+2, resolution='h')

x, y = m(lons,lats)
u, v = np.arange(0, 51, 10), np.arange(0, 51, 10)
barbs = m.barbs(x, y, u, v)

m.drawcoastlines()
m.fillcontinents()

x_size, y_size = 0.8, 0.4
x0, y0 = m(x[-1] - x_size/2., y[-1] - y_size/2.)
x1, y1 = m(x[-1] + x_size/2., y[-1] + y_size/2.)
im = plt.imshow(plt.imread('mslr86.png'), extent=(x0, x1, y0, y1))

plt.show()

Which produces an image that looks like

Update: if you want the image to remain a fixed size, independent of the zoom, see Joe's answer.