Explain spatial data types - geometry and geography in sql server 2008
Location based data can be seamlessly consumed and extended by the enterprises with the comprehensive support of spatial data types.Geometry data type:
This data type supports a flat 2D surface with points of XY coordinates. The points could be on line string, on lines and also mark the polygon edges. There are certain methods like STintersects, STarea, STDistance and STTouch which uses geometry data types.Geography data type:
The similar methods of geometry data type are used in this data type. But the type reflects on curved 2D surfaces. The ST* functions are utilized but the results in the curvature.
DECLARE @gmtry geometry; Certain observations need to be considered. They are:
SET @gmtry = geometry::STGeomFromText('POINT (3 4)', 0);
DECLARE @grphy geography;
SET @grphy = geography::STGeomFromText('POINT (3 4)', 4326);
- A polygon is tried which is larger than a hemisphere, an ArgumentException is thrown.
- If the returned result is larger than a hemisphere, then a NULL value is returned.