Working with Geography Data
The GEOGRAPHY data type is also implemented as a .NET common language runtime data type in SQL Server. Unlike the GEOMETRY data type in which locations are defined in terms of X and Y coordinates that can conceivably extend to infinity, the GEOGRAPHY type represents data in a round-earth coordinate system. Whereas flat models do not “wrap around,” the round-earth coordinate system does wrap around such that if you start at a point on the globe and continue in one direction, you eventually return to the starting point.
Because defining points on a ball using X and Y is not very practical, the GEOGRAPHY data type instead defines points using angles. The SQL Server GEOGRAPHY data type stores ellipsoidal (round-earth) ...
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