Error java NullPointerException

 
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Hello everyone

I am trying to do the exercice frome the 2019 ISU with the Uganda spatial context

However, when I try to execute the NDVI model, I always receive this Java error herebelow


Do you know where lies the issue ?

Thanks in advance

Noé Hanciaux

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    5 -respuestas

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      Thanks, Kenneth Bagstad for following up. I found some clues but not sure since my model(land classification) keeps running. I changed the grid to a greater value(e.g: 90 m, 100m, 200m) I didn't get the java related error but the model keeps running for hours without any output which is strange! 
      Any idea what might be the problem?  Ferdinando Villa / Stefano Balbi 

      1. Kenneth Bagstad

        What changes did you make to the code to take care of the error?

        As far as running for hours, I would start by using a much coarser spatial resolution, to make sure everything runs as expected. Go to 1 km, even 2 km first, then try finer resolution as needed - as we've talked about before, your context is huge, so will give you very large cell counts. If you know the total area if your context, you can easily calculate the rough # of grid cells at different resolutions, and figure out what a reasonable tradeoff is between spatial resolution and runtime.

      2. ehsanpashanejad

        I changed the grid in my context. In the initial code, it was 30 m. 

        observe earth:Region named ...over space ...
           grid= "1000 m",
           projection= "EPSG:4326" 
          ),
         time(year=2015);

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    2.  
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      Stefano Balbi / Ferdinando Villa , any ideas here? ehsanpashanejad posted this as a reply rather than a comment which may have prevented a notification. This is related to the final remaining comment in 1.5 Annotating a context for analysis - I don't think we've yet documented a clear explanation of why and when temporal annotation of a context is needed, or what errors can result from doing it incorrectly.

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        Hello everyone, 

        I am facing the same issue with my data, not the Uganda example! Here I attached the code that I used to define my context and model(land classification). The last screenshot is the result without defining the context in Klab( I just drag the model, and it's working!). 
        I tried this model in a subset area in this region(just in UTM N13) which was working. I think it's maybe due to the projection system but wonder why since it is NAD83 / Canada Atlas Lambert(EPSG: 3978). 

        The error that I am facing is java related one and telling "Cannot extract data from resource...". 

        Thank you!



         



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          Thank you for your response. It is now fixed

          But I have another problem: it now says that it cannot extract the data from the resource

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            Definitely a bug, but probably due to the fact that we now avoid specifications with no temporal location, so they don't get much testing. Try adding time to the context in the "observe" statement that creates the context, e.g 

            observe ... over space (....), time(year=2020);

            and see if this fixes the problem.

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