Add a scale bar and a north arrow

[ErikSeras]

• geemap version: 0.8.3
• Python version: 3.6.9
• Operating System: Google Colab

Description

I used COPERNICUS/S2_SR to be able to represent the Lewato volcano eruption, Indonesia.

How can I add a scale bar and a north arrow?

What I Did

import ee
import geemap.eefolium as geemap
from geemap import cartoee as cee

%pylab inline

try:
    ee.Initialize()
except Exception as e:
    ee.Authenticate()
    ee.Initialize()

point = ee.Geometry.Point(123.488, -8.284)

volcano = ee.ImageCollection("COPERNICUS/S2_SR").filterBounds(point).filterDate("2020-11-28", "2020-12-04").first()

plt.figure(figsize=(16, 12))

region = [123.3,-8.5,123.8,-8.18]
vis = {'min':0,'max':6000, 'bands':'B4,B3,B2'}

ax = cee.get_map(volcano, region=region, vis_params=vis)
cee.add_gridlines(ax,interval=(0.1,0.1),linestyle=":")

ax.set_title(
    label = 'Lewato volcano 2020-11-29',
    fontsize = 15
)

plt.show()

Thanks for your help!

[KMarkert]

To add a scale bar and north arrow one would need to do draw on the figure yourself using matplotlib/cartopy graphics elements. Unfortunately, there really no easy solution available for this right now, although it looks like others have shared code to get started. Here is a thread on stackoverflow regarding this same problem: https://stackoverflow.com/questions/32333870/how-can-i-show-a-km-ruler-on-a-cartopy-matplotlib-plot and another issue thread on the cartopy repo: SciTools/cartopy#490.

I don't think we would want to consider this a feature request for this package given this is more low-level functionality and would be best if implemented in cartopy. I hope this helps.

P.S. That is a pretty amazing image that S2 captured!

[ErikSeras]

Thank you very much for your help @KMarkert.

[giswqs]

Thanks to the stackoverflow sample code. I have added two more functions to cartoee, add_scale_bar() and add_north_arrow(). See notebook example - cartoee_scalebar.ipynb

@KMarkert @jdbcode @ErikSeras @GokulGeo