Why calculating home run distances is like measuring sea level

When a home run lands in the outfield stands-- or perhaps hits a pole or façade-- the ball stops moving at a point elevated from the field level, sometime by as much as 200 feet. To figure out how far a ball would have traveled if unimpeded-- and therefore get the "true distance" of a home run, we need the exact trajectory the ball took and then extend that to field level.

One of the more interesting analytical pieces I've read about how baseball statistics have changed in the IoT era.