import numpy as np
    import matplotlib.pyplot as plt
    import cartopy.io.img_tiles as cimgt
    import cartopy.crs as ccrs

    fig, ax1 = plt.subplots(num="TestXX", figsize=(30/2.54, 25/2.54))
    
    #add a map of the Netherlands
    request = cimgt.OSM()
    ax1=plt.axes(projection=request.crs)
    ax1.set_extent([3.25, 7.35, 50.45, 53.55],ccrs.PlateCarree())
    ax1.add_image(request, 10)
    
    #create a rectangular grid a little smaller than the map
    #with cell sizes of 0.01 degree filled with random values
    nx=400
    ny=300
    xedges=np.linspace(3.3, 7.3, nx)
    yedges=np.linspace(50.5, 53.5, ny)
    zvalues=np.random.random((nx, ny))
    
    ax1.pcolormesh(xedges, yedges, zvalues.T ,\
                   alpha=0.3, shading='auto', transform=ccrs.PlateCarree())
        
    plt.show()