LINQ POI proximity
Can anybody tell me how I can get the distance from a given longitude, latitud开发者_运维百科e to a POI (longitude, latitude) stored in SQL Server DB?
While not a SQL answer, I always recommend this explanation for how to calculate distances between lat-lng - http://www.movable-type.co.uk/scripts/latlong.html
For SQL Server, assuming you are using SQL Server 2008, then you can use the native SQL geography types. However, sadly I don't think these map well to Linq-2-Sql so you will probably need to wrap them within stored procedures.
See:
- getting started with geo types - http://msdn.microsoft.com/en-us/library/bb895266.aspx
- determining relationships (which includes STDistance) - http://msdn.microsoft.com/en-us/library/bb964709.aspx
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