sql geography to dbgeography?

Question

Maybe I'm missing something. I have a sql server column of the "Geography" datatype.

I want to use the DbGeography type in my c# code. Any way to cast or convert from sql's geography to dbgeography?

Answer 1

When the performance is of any importance, the well-known binary should be used instead of the well-known text:

var newGeography = DbGeography.FromBinary(theGeography.STAsBinary().Value);

There is an overload using a SRID, if that is important. In my simple test with a 1,000 reasonably complicated polygons the binary-based approach is 4 times faster than the text-based one:

* Binary-based conversion
Run 1: 1948
Run 2: 1944
Run 3: 1959
Run 4: 1979
Run 5: 1988
Average: 1963.6

* Text-based conversion
Run 1: 8527
Run 2: 8553
Run 3: 8596
Run 4: 8535
Run 5: 8496
Average: 8541.4

Answer 2

Sorry for the late response - but saw this whilst searching for something else.

Simply do the following:

SqlGeography theGeography;
int srid = 4326; // or alternative

DbGeography newGeography = DbGeography.FromText(theGeography.ToString(), srid);

To reverse it:

DbGeography theGeography;
SqlGeography newGeography = SqlGeography.Parse(theGeography.AsText()).MakeValid();

Hope that helps!

Answer 3

The provided solution seems to be ok if you are not running EF6. With early versionsit´s ok, but with EF6, we shouldnt make references to this assembly. It turns EF litle crazy.