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) ...
Get Microsoft® SQL Server 2008 R2 Unleashed now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.