SQL geometry::STGeomFromText throwing error and stopping job - sql

Question

Folks,
Got an odd one for you.
I've got a stored procedure I use to parse some tabular data to create proper SQL geometry objects.
The SP makes use of the function MakeValid().
In my case I have found some objects that fail the test. These do not break the stored procedure however. The Stored procedure is happy to run and simply show the error in the results.
Msg 6522, Level 16, State 1, Line 257 A .NET Framework error occurred
during execution of user-defined routine or aggregate "geometry":
System.FormatException: 24306:
However when I execute this SP in a scheduled job, the first time it encounters one of these exceptions the job fails and the SP stops running.
I'm actually not sure what to do here. I've tried a TRY..CATCH block but this doesn't stop the error being raised and the job exits anyway.
So while it's a MakeValid function that's raising the error I would imagine an SP that encounters a function error would cause the same issue.
Any thoughts how I might handle this? BTW I have no control over the input quality other than to flag the errors and then go back and repair them. I'd still like the rest of the valid records to be processed though.
Here's the operable section of code.
SET #GEOM = geometry::STGeomFromText(#GEOMWKT, 4326)
IF #GEOM.STIsValid() = 0
BEGIN
BEGIN TRY
SET #GEOM = #GEOM.MakeValid()
END TRY
BEGIN CATCH
Print 'Error here'
END CATCH
END
Here is an example of an invalid geometry that throws an error.
SET #GEOM = geometry::STGeomFromText('LINESTRING(-121.895652 37.37225, -121.895652 37.37225)', 4326)
Thanks for any and all assistance.

Answer 1

I'm having a hard time validating that this will work for you (i.e. my local instance is too good at calling MakeValid()), but this might just work for you.
using Microsoft.SqlServer.Server;
using Microsoft.SqlServer.Types;
using System.Data.SqlTypes;
public partial class UserDefinedFunctions
{
[SqlFunction]
public static SqlGeometry TryMakeValid_geometry(SqlGeometry g)
{
SqlGeometry r;
try
{
r = g.MakeValid();
}
catch (System.Exception)
{
r = SqlGeometry.Null;
}
return r;
}
[SqlFunction]
public static SqlGeometry TryParseWKT_geometry(SqlString wkt)
{
SqlGeometry r;
try
{
r = SqlGeometry.Parse(wkt).MakeValid();
}
catch
{
r = SqlGeometry.Null;
}
return r;
}
}
Deploy this CLR to your database and call the function with your geometry instance. It should return NULL if the call to MakeValid() fails.

Answer 2

OK this is the answer that I'm going with but significant credit goes to Ben Thul for the CLR which achieves the same result using a different method.
The realisation is more correctly understanding the question. I made two mistakes. The first was not realising the error I was trying to catch was outside the TRY..CATCH block. The second was believing I needed to try and validate the WKB expression of the geometry. In fact, the following method allows the validation of the WKT before attempting to create a WKB. The following method identifies the invalid WKT, sets a TRUE/FALSE condition. With the WKT validated a valid WKB can be safely created.
Once I understood the question asking the right question turned up the solution here.
https://gis.stackexchange.com/questions/66642/detecting-invalid-wkt-in-text-column-in-sql-server
I have adapted the code to suit my implementation.
/*REVISED CODE*/
DECLARE #valid bit
DECLARE #GEOMWKT varchar(max)
DECLARE #GEOM geometry
Set #GEOMWKT = 'LINESTRING(-121.895652 37.37225, -121.895652 37.37225)'-- Test faulty value
Set #valid = 1
--Test WKT
BEGIN TRY --The is the test here.
SET #valid = geometry::STGeomFromText(#GEOMWKT, 4326).STIsValid()--We don't try to
END TRY --MakeValid(). No point.
BEGIN CATCH
SET #valid = 0
END CATCH
--Now that we know whether the WKT will pass or fail we can operate in a known
--state and avoid raising an error
IF #valid = 1
BEGIN
SET #GEOM = geometry::STGeomFromText(#GEOMWKT, 4326)--Safely create a valid WKB
END
ELSE
BEGIN
SET #GEOM = geometry::STGeomFromText('POINT EMPTY', 4326)-- Set geometry to empty on fail
Print 'Geometry Fail'
END