SQL Server 2008 was a major upgrade and one of its new features was support for new data types such as spatial data types. Spatial data types will be increasingly adopted in dealing with globalization and handling the distributed nature of resources and events. Presently it supports 2D data with a possible 3D addition in the future.
Spatial data is basically of two types, the geometry type for flat-earth situations that can be handled by Euclidean geometry principles and the other the Geography type for situations dealing with locations on the ellipsoid or round-earth handled by spherical geometry.
In the hyper-linked article a clear guide to understanding spatial coordinates is presented in five easy to follow steps.
Step 1: Gather the resources
Step 2: Create a database
Step 3: Create a table to hold geography data type
Step 4: Populate the table with sample data
Step 5: Populating the geography data type the table's column
With this you can do some geocalculations.
EASY GUIDE TO GEOGRAPHY DATA TYPE IN SQL SERVER 2008
P.s: You can read it for free by becoming a guest.