Spatial data types support in Linq2Sql or EF4

Question

Does anyone know (ideally, with a reference), whether the VS2010 release of LinqToSQL or EntityFramework v4 will support queries over the SQL 2008 spatial data types?

Answer 1

Here's a workaround to get it working in Entity Framework / LINQ to Entities:

You can use a database View to return Well-Known-Text (using "geometry.ToString()" in the query) or Binary. Then once the resulting rows are returned, just convert the string/binary to a SqlGeometry object in .NET.

Here's a sample query used to build a View that converts a "Location" field of geometry type to a Well-Known-Text String:

SELECT ID, Name, Location.ToString() as Location FROM MyTable

Here's an example of querying the resulting entities that have a "Location" field that contains a Well-Known-Text or String representation of the "geography" object:

var e = new MyApp.Data.MyDataEntities(connectionString);
var items = from i in e.MyTables
            select i;

foreach (var i in items)
{
    // "Location" is the geography field
    var l = SqlGeography.Parse(i.Location);
    var lat = l.Lat;
    var lng = l.Long;
}

One additional thing, is you'll need to do any spatial based queries within Stored Procedures, since you don't want to pull ALL the data from the table into .NET in order to perform your own spatial query using LINQ.

This isn't an elegent as natively supporting SQL Spatial Types, but it'll get you running with Entity Framework and SQL Spatial simultaneously.