x = np.array(lats)
        y = np.array(lons)
        z = np.array(data)
        xi = np.linspace(lat_min, lat_max, ngrid)
        yi = np.linspace(lon_min, lon_max, ngrid)
        zi = griddata(x, y, z, xi, yi)

        m = Basemap(
            projection = 'merc',
            llcrnrlat=lat_min, urcrnrlat=lat_max,
            llcrnrlon=lon_min, urcrnrlon=lon_max,
            rsphere=6371200., resolution='l', area_thresh=10000
            lat_ts = 20, resolution = 'c'
        )

        # draw parallels
        delat = 10.0
        parallels = np.arange(0., 90, delat)
        m.drawparallels(parallels, labels=[1,0,0,0], fontsize=10)

        # draw meridians
        delon = 10.
        meridians = np.arange(180.,360.,delon)
        m.drawmeridians(meridians,labels=[0,0,0,1],fontsize=10)

        # draw map features
        m.drawcoastlines(linewidth = 0.50)
        m.drawcountries(linewidth = 0.50)
        m.drawstates(linewidth = 0.25)

        cs = m.contour(xi, yi, zi, 20, linewidths = 1)
        plt.show()