mongodb/mongo — pull request #588 by rps (2013-12-14 07:59:15+00:00)
Title: Change constant Earth radius to mean radius rather than equatorial

MongoDB tests and documentation utilize mean Earth radius (6371km) rather than equatorial radius (6378.1km). Because Earth is not a perfect sphere, mean radius may be a more appropriate constant.

Ref: https://github.com/mongodb/mongo/pull/580#issuecomment-30535697