Getting the number of coordinate dimensions of a geometry/geography object in SQL Server 2008

The OGC standard has an STDimension() method defined on geometry/geography objects and this is implemented in SQL Server 2009. This function returns the inherent (or topological) dimensionality of an object: for a point this is 0; for a linestring this is 1; and for a polygon this is 2. name dim Point 0 LineString 1Read More

STDumpPoints: A Function that Dumps the Vertices/Points in a geometry

I often find I need to manipulate the points of a geometry/geography object directly in SQL. Oracle has the neat TABLE function mdsys.sdo_util.GetVertices( sdo_geometry ) for this. Since SQL Server 2008 does not have such a function I found I had to write it myself. I prefer to program in TSQL using the OGC geometry/geographyRead More

toGeography and toGeography Conversion Functions for SQL Server 2008 Spatial

I have been doing some SQL Server 2008 programming lately and have come across the fact that TSQL does not allowing a programmer to create overloaded functions. This is an issue, when programming SQL Server 2008 Spatial, because of use of its implementation of two different data types for geodetic and projected data: geography andRead More

Spatial Sorting of Data via Morton Key For Oracle Spatial/Locator

I have often advocated the use of a spatial sort when loading static spatial data into Oracle (See 1. Spatially sort read-only data. in my article on performance tips). The idea here is to try and place spatial data that is close together in space (called spatial autocorrelation), close together on disk. Then, when theRead More

Write text file with spatial data from SQL Server 2008

Trivial I know, but here is a method for writing the result of a query (select) to a text file where the query contains either geometry or geography data. To do this we will use the xp_cmdshell stored procedure to call the external sqlcmd tool. To do this, first, we must allow SQL Server toRead More

Swapping Ordinates in an SDO_GEOMETRY object

I was chatting with a friend and colleague on the telephone today when he mentioned that his project was being delayed because they had been provided some SDO_GEOMETRY data in which the latitude and longitude ordinates had been swapped out of their normal positions. For those who don’t know, latitude/longitude data (known as geodetic data)Read More