Trying to convert geometry to geography keep failing in MSSQL 2012?

Question

In MSSQL I have LineString in Geometry type. When I try to convert it to geography using : GEOGRAPHY::STGeomFromText(geom.MakeValid().STUnion(geom.MakeValid().STStartPoint().MakeValid()).STAsText(),4326) I still get error that Msg 6522, Level 16, State 1, Line 19 A .NET Framework error occurred during execution of user-defined routine or aggregate "geography":System.ArgumentException: 24200: The specified input does not represent a valid geography instance. Use MakeValid to convert the instance to a valid instance. Note that MakeValid may cause the points of a spatial instance to shift slightly.System.ArgumentException: at Microsoft.SqlServer.Types.SqlGeography..ctor(GeoData g, Int32 srid) at Microsoft.SqlServer.Types.SqlGeography.GeographyFromText(OpenGisType type, SqlChars taggedText, Int32 srid) Any idea how I can convert it to geography ? Any idea how I can share the LineString ? Its very long (exceeding this post body length)

Answer 1

The error message suggests that your input geometry is invalid, which is preventing it from being converted to geography. The error message also suggests using the MakeValid method to fix any invalid geometry, but it seems like you are already doing that in your query.

Without seeing the actual LineString, it's difficult to diagnose the issue. However, here are a few things you could try:

1. Check if the input geometry is valid: You can use the STIsValid() method to check if the geometry is valid. If it returns false, then the geometry is invalid and needs to be fixed using the MakeValid method.
2. Simplify the LineString: If the LineString is very long, it could be causing the error. Try simplifying it using the STSimplify() method before converting it to geography.
3. Try a different conversion method: Instead of using the STGeomFromText() method, try using the STGeomFromWKB() method to convert the geometry to geography.
4. Split the LineString into smaller segments: If the LineString is too long, try splitting it into smaller segments using the STLineSubstring() method and then convert each segment to geography separately.

Regarding sharing the LineString, you can store it in a file or a database table and provide a link or instructions on how to access it.