'The specified input does not represent a valid geography instance' exception when using SqlGeographyBuilder

Question

I\'ve written a small application that reads in from a series of KML files and then converts them into the Microsoft.SqlServer.Types.SqlGeography type using the

Answer 1

I've had the same problem and solved it using a project called Sql Server Spatial Tools (http://sqlspatialtools.codeplex.com).

It has (among other interesting stuff) these two methods:

• MakeValidGeographyFromGeography
• MakeValidGeographyFromText (which receives a WKT string)

They modify the points so that it conforms to the geography restrictions.

It works really, really well, and I've used it for several months now without any problem.

Answer 2

I had this same error, but it turned out to be a polygon ring orientation problem. A simple matter of flipping the order of the coordinate arrays solved the problem.

To illustrate, this fails with the above error:

 select geography::STGeomFromText ('Polygon  ( (10 10, 10 20, 20 20, 20 10, 10 10))',4326)

whereas this works:

 select geography::STGeomFromText ('Polygon  ( (10 10, 20 10, 20 20, 10 20, 10 10))',4326)

Note that I'm not flipping the x,y pairs within a point, I am flipping the order of the entire point array (e.g. {pt1, pt2, pt3, pt4, pt5} becomes {pt5, pt4, pt3, pt2, pt1}