On the September 2017 Equinox, 23 amateurs from 9 countries measured the shadows cast by a vertical pole at solar noon
They gave their data, photos of the measurements, and their positions to a Youtuber called Sly Sparkane
All the photos and GPS locations are is shown in the video
He mapped them onto a flat plane and saw no correlation indicating a close local Sun
Then he mapped them onto a sphere and saw all angles fall within one degree of parallel
This is what Eratosthenes did over 2000 years ago, but he did it with many more data points
Flerfs will sometimes reply with "But shadows don't prove it" and show an image with two shadows
And they're right, two shadows is consistent with a Flat Earth
But once you go more than 2, then the results are definitive because there is no correlation in the shadow angle when mapped onto a flat plane
Flerfs will also say that all measurements must be taken at the same time
The measurements are all taken at solar noon, when the shadow is the shortest and thus the sun is highest
That is the only way to eliminate the variable of the declination angle of the sun.
The Flat Earth is thus disproven by sticks and shadows
https://youtu.be/V03eF0bcYno?t=420 