# GenerateGrid exception **URL:** \ **Category:** WinForms\ **Created:** [September 8, 2015, 10:09am UTC](https://community.thinkgeo.com/t/generategrid-exception/2605 "2015-09-08T10:09:43Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Scott5](https://community.thinkgeo.com/letter_avatar_proxy/v4/letter/s/e480ec/32.png) [@Scott5](https://community.thinkgeo.com/u/Scott5)\ **Post date:** [September 8, 2015, 10:09am UTC](https://community.thinkgeo.com/t/generategrid-exception/2605/1 "2015-09-08T10:09:43Z")
Hello Forum, We’re generating some colour layers using GridFeatureLayer (similar to those used in your "Isolines With Kriging" code sample). To do this we need to call the static GridFeatureSource.GenerateGrid method using an appropriate interpolation model. We use a LinealKrigingGridInterpolationModel with 5 reference points (Desktop Edition 9). Our data points are a scattering of values arranged basically in a grid formation but with patches often missing, and it generally causes no problems when generating the grid. However, on occasion, the method fails and does so in a manner from which we cannot seem to recover. In the debugger, we receive the following message: `System.InvalidOperationException was unhandledMessage: An unhandled exception of type ‘System.InvalidOperationException’ occurred in MapSuiteCore.dllAdditional information: The matrix cannot be inversed, please check if the input data is valid. For example 2 points with different values should not have the same coordination.` That’s fine and all, but the exception cannot be caught on our side, it seems, and instead brings down our service. We’d much rather skip the calculation and carry on. I’ll append the stacktrace below, as well as attach an x,y,z data set (in metre map units) which causes the issue for us when we try to generate a grid with 100 cells along the shortest side. Are there any app domain considerations we should be making here which might prevent the exception from propagating from the ThinkGeo code? If you have any ideas on how we can get around this issue, I’d very much appreciate it. Many thanks, Scott D. --------- `> MapSuiteCore.dll!ThinkGeo.MapSuite.Core.KrigingGridInterpolationModel.ahw=(int nPn, double x, double y) Unknown  MapSuiteCore.dll!ThinkGeo.MapSuite.Core.KrigingGridInterpolationModel.InterpolateCore(ThinkGeo.MapSuite.Core.RectangleShape cellExtent, ThinkGeo.MapSuite.Core.GridDefinition gridDefinition) Unknown  MapSuiteCore.dll!ThinkGeo.MapSuite.Core.GridInterpolationModel.Interpolate(ThinkGeo.MapSuite.Core.RectangleShape cellExtent, ThinkGeo.MapSuite.Core.GridDefinition gridDefinition) Unknown  MapSuiteCore.dll!xRM=.Cjc=.DDc=(object objStateInfo) Unknown  mscorlib.dll!System.Threading.QueueUserWorkItemCallback.WaitCallback_Context(object state) Unknown  mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx) Unknown  mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx) Unknown  mscorlib.dll!System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem() Unknown  mscorlib.dll!System.Threading.ThreadPoolWorkQueue.Dispatch() Unknown  mscorlib.dll!System.Threading._ThreadPoolWaitCallback.PerformWaitCallback() Unknown` [001\_data.txt](https://community.thinkgeo.com/uploads/default/original/1X/e0c426dfa56f85efecdb46de305ba393bfdfdc3d.txt) (16.4 KB) ---
**Author:** ![Ethan](https://community.thinkgeo.com/user_avatar/community.thinkgeo.com/ethan/32/19964_2.png) [@Ethan](https://community.thinkgeo.com/u/Ethan)\ **Post date:** [September 9, 2015, 5:28am UTC](https://community.thinkgeo.com/t/generategrid-exception/2605/2 "2015-09-09T05:28:40Z")
Hi Scott,      If you visit our sample data in IsoLinesWithKriging sample, you can see the data is splited by “,” and in the project code please visit the function GetWellDepthPointDataFromCSV, it contains a line: string[] parts = line.Split(’,’);      You can modify it for your data or modify your data to separated by “,”.      I tried to modify the data to separated by “,” and hadn’t met the exception you mentioned.      Regards,      Don ---
**Author:** ![Scott5](https://community.thinkgeo.com/letter_avatar_proxy/v4/letter/s/e480ec/32.png) [@Scott5](https://community.thinkgeo.com/u/Scott5)\ **Post date:** [September 9, 2015, 10:56am UTC](https://community.thinkgeo.com/t/generategrid-exception/2605/3 "2015-09-09T10:56:18Z")
Thanks for the reply. The format of the data file is not relevant here, our application doesn’t actually read it in that way. I have modified your Kriging sample application to reproduce the error and have attached it here. It just needed to account for the difference in projection when reading the data file, and to put a try/catch block around the GenerateGrid call. If you start the application and change the number of reference points to 4, the exception occurs as described above. This is what is happening for us under various conditions. As I mentioned in my original post, while the exception is in itself a problem, the bigger issue is that the entire application crashes when the exception is raised down in the MapSuiteCore. We would like to be able to recover from the problem. If you have any advice, we would be most grateful. Regards, Scott D. ![](https://community.thinkgeo.com/uploads/default/original/2X/3/3116cff40c182d4302d7915e26f634318eb67674.png) [001\_IsoLinesWithKriging.zip](https://community.thinkgeo.com/uploads/default/original/2X/5/5ef695cf3f1d1037d041fad8e04b2d62c1f9d0b9.zip) (142 KB) ---
**Author:** ![Troy](https://community.thinkgeo.com/letter_avatar_proxy/v4/letter/t/85f322/32.png) [@Troy](https://community.thinkgeo.com/u/Troy)\ **Post date:** [September 10, 2015, 4:21am UTC](https://community.thinkgeo.com/t/generategrid-exception/2605/4 "2015-09-10T04:21:09Z")
Hi Scott, Thanks for the sample, it is very easy for us to recreate the issue. Currently, we are working on it and will give you a response asap. Thanks, Troy ---
**Author:** ![Scott5](https://community.thinkgeo.com/letter_avatar_proxy/v4/letter/s/e480ec/32.png) [@Scott5](https://community.thinkgeo.com/u/Scott5)\ **Post date:** [September 14, 2015, 11:04am UTC](https://community.thinkgeo.com/t/generategrid-exception/2605/5 "2015-09-14T11:04:43Z")
Hello again,      Just wondering if there is any news on this, either a fix or a work-around? Any information much appreciated.      Regards,   Scott D. ---
**Author:** ![Ethan](https://community.thinkgeo.com/user_avatar/community.thinkgeo.com/ethan/32/19964_2.png) [@Ethan](https://community.thinkgeo.com/u/Ethan)\ **Post date:** [September 15, 2015, 4:34am UTC](https://community.thinkgeo.com/t/generategrid-exception/2605/6 "2015-09-15T04:34:54Z")
Hi Scott,      That crash caused by exception is thrown in child thread, for now we cannot fix that in our end, as below is a workaround, please let us know whether that can work for you.      I think you can solve that like this:      ` public class MyLinealKrigingGridInterpolationModel : LinealKrigingGridInterpolationModel{    double noDataValue = -9999; // You can modify this value equal the value in function CreateGridFile of sample.cs    public MyLinealKrigingGridInterpolationModel()        : base(new Dictionary(), 5)    { }    public MyLinealKrigingGridInterpolationModel(IDictionary points)        : base(points, 5)    { }    public MyLinealKrigingGridInterpolationModel(IDictionary points, int numberOfRefreancedPoints)        : base(points, numberOfRefreancedPoints)    { }    protected override double InterpolateCore(RectangleShape cellExtent, GridDefinition gridDefinition)    {        double result;        try        {            result = base.InterpolateCore(cellExtent, gridDefinition);        }        catch (Exception)        {            result = noDataValue;        }        return result;    }}`      The use the new class: interpolationModel = new MyLinealKrigingGridInterpolationModel(wellDepthPointData, referencingPointCount);      That will solve your issue.      Regards,      Don ---
**Author:** ![Scott5](https://community.thinkgeo.com/letter_avatar_proxy/v4/letter/s/e480ec/32.png) [@Scott5](https://community.thinkgeo.com/u/Scott5)\ **Post date:** [September 15, 2015, 10:50am UTC](https://community.thinkgeo.com/t/generategrid-exception/2605/7 "2015-09-15T10:50:20Z")
Thank you for the response, much appreciated.      I will give this a try now.      Regards,   Scott D. ---
**Author:** ![Troy](https://community.thinkgeo.com/letter_avatar_proxy/v4/letter/t/85f322/32.png) [@Troy](https://community.thinkgeo.com/u/Troy)\ **Post date:** [September 15, 2015, 8:41pm UTC](https://community.thinkgeo.com/t/generategrid-exception/2605/8 "2015-09-15T20:41:04Z")
Scott,      Please let us know if the issue still persists.      Thanks,      Troy ---
**Author:** ![Scott5](https://community.thinkgeo.com/letter_avatar_proxy/v4/letter/s/e480ec/32.png) [@Scott5](https://community.thinkgeo.com/u/Scott5)\ **Post date:** [September 16, 2015, 6:47am UTC](https://community.thinkgeo.com/t/generategrid-exception/2605/9 "2015-09-16T06:47:36Z")
That fixed the problem, and didn’t stop us generating the contours either. This is great news.      Thanks again for the assistance.      Regards,   Scott D. ---
**Author:** ![Troy](https://community.thinkgeo.com/letter_avatar_proxy/v4/letter/t/85f322/32.png) [@Troy](https://community.thinkgeo.com/u/Troy)\ **Post date:** [September 16, 2015, 8:17pm UTC](https://community.thinkgeo.com/t/generategrid-exception/2605/10 "2015-09-16T20:17:09Z")
Great to hear Don’t suggestion works.       Thanks,   Troy