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I am analyzing the accuracy of the STDistance function for geographical objects in SQL Server 2008, in order to understand its behaviour better I need to find the underlying formula.

Does anyone knows which formula is used in SQL Server, haversine?

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may be helpful for you stackoverflow.com/questions/15975066/… –  Sunil Apr 22 '13 at 12:58
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up vote 1 down vote accepted

Microsoft (due mostly to a lack of knowledge about geodesics) elected to define geographical distances along great ellipses and this is what STDistance on Geographic objects returns. For the formulas that are used see Kallay, Geometric algorithms on an ellipsoid earth model (2008), http://dx.doi.org/10.1145/1463434.1463487 Also relevant is Kallay, Defining edges on a round earth (2007), http://dx.doi.org/10.1145/1341012.1341087 (be warned that this paper contains several misstatements about geodesics).

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