SQL Server supports two spatial data types: Geometry : Stores data based on a flat (Euclidean) coordinate system. The data type is often used to store the X and Y coordinates that represent lines, points, and polygons in two-dimensional spaces. Geography : Stores data based on a round-earth coordinate system.

Spatial data are of two types according to the storing technique, namely, raster data and vector data. Raster data are composed of grid cells identified by row and column. The whole geographic area is divided into groups of individual cells, which represent an image.

Spatial data represents information about the physical location and shape of geometric objects. These objects can be point locations or more complex objects such as countries, roads, or lakes. SQL Server supports two spatial data types: the geometry data type and the geography data type.

SQL Server also supports the geography data type, which stores ellipsoidal (round-earth) data, such as GPS latitude and longitude coordinates.

A Geometry object is just a 2D, flat polygon. A Geography object on the other hand, is a 3D (or even 4D) polygon, that has the same curve as the shape of the earth. That means that the difference between 2 point isn’t calculated in a straight line, but it’s need to consider the curvature of the earth.

precision you should use DECIMAL . Latitudes range from -90 to +90 (degrees), so DECIMAL(10,8) is ok for that, but longitudes range from -180 to +180 (degrees) so you need DECIMAL(11,8) . The first number is the total number of digits stored, and the second is the number after the decimal point.

Every geometric shape has a spatial reference system associated with it, and each such reference system has a Spatial Reference System ID (SRID). The SRID is used to tell which spatial reference system will be used to interpret each spatial object.

In most GIS software data is organized in themes as data layers. This approach allows data to be input as separate themes and overlaid based on analysis requirements. This can conceptualized as vertical layering the characteristics of the earth’s surface.

The planar spatial data type, geometry, is implemented as a common language runtime (CLR) data type in SQL Server. This type represents data in a Euclidean (flat) coordinate system. SQL Server supports a set of methods for the geometry spatial data type.

The SQL Server geography data type stores ellipsoidal (round-earth) data, such as GPS latitude and longitude coordinates. SQL Server supports a set of methods for the geography spatial data type.

The planar spatial data type, geometry, is implemented as a common language runtime (CLR) data type in SQL Server. This type represents data in a Euclidean (flat) coordinate system. SQL Server supports a set of methods for the geometry spatial data type.

Microsoft did indeed introduce geospatial data types, as well as a host of functions to support those data types, in SQL Server 2008. To me this is one of the most exciting enhancements in that release. The data types and functions used to support geospatial data are based on standards set forth by the Open Geospatial Consortium .

SQL Server supports a set of methods for the geometry spatial data type. These methods include methods on geometry that are defined by the Open Geospatial Consortium (OGC) standard and a set of Microsoft extensions to that standard. The error tolerance for the geometry methods can be as large as 1.0e-7 * extents.

Spatial Types – geometry (Transact-SQL) The planar spatial data type, geometry, is implemented as a common language runtime (CLR) data type in SQL Server. This type represents data in a Euclidean (flat) coordinate system. SQL Server supports a set of methods for the geometry spatial data type.