More visualization examples

- north arrow, scalebar
- inset (to locate study area) (see https://matplotlib.org/3.3.1/gallery/subplots_axes_and_figures/zoom_inset_axes.html#sphx-glr-gallery-subplots-axes-and-figures-zoom-inset-axes-py, https://basemaptutorial.readthedocs.io/en/latest/locator.html#inset-locator)
- customize title, legend, ...