the algorithm for the figure is to first fetch the top 50 users using the same API call used here: https://www.inaturalist.org/observations?place_id=6903&view=observers
but to calculate the centroid for each of these users, its just looking at all observations within the bounding box around the country rather than using the country boundaries to make the calculation quicker.
That means while amarzee is in the top 50 users based on obs inside the boundary, and the icon is scaled based on the number of obs inside the boundary, the centroid is also considering Korean obs that are inside the bounding box that encompasses China but outside the China boundary.
I know its not perfect, but the centroid calculation is slow to compute and using the country boundaries rather than just the bounding box makes it even slower