STIntersects between SqlGeography types in a condition IF

Question

I use the SqlGeography type.

Is there a difference between the following uses of STIntersects function:

this.Location.STIntersects(another.Location)

and

this.Location.STIntersects(another.Location).Value

and

this.Location.STIntersects(another.Location).Equals(1)

?

I get different results.

Answer 1

Matthew Evans has given complete answer. Here is same answer phrased differently.

• Location.STIntersects(another.Location) returns a SqlBoolean with true in it if the locations intersect otherwise it returns a false.
• Location.STIntersects(another.Location).Value returns true or false of type System.Boolean rather than SqlBoolean above.
• Location.STIntersects(another.Location).Equals(1) returns "true if object is an instance of SqlBoolean and the two are equal; otherwise, false.". Hence it will always return false the way you are comparing.

Answer 2

The problem is that the SqlIntersects method doesn't return a bool, it returns a SqlBoolean structure

Assuming your geographies intersect, I would assume you get the following values:

this.Location.STIntersects(another.Location) => true

this.Location.STIntersects(another.Location).Value => returns value proprerty of SqlBoolean return value => true

this.Location.STIntersects(another.Location).Equals(1) => compares SqlBoolean structure to value 1, and returns false