Error resource grid (2009-09-06)

[Old Forum Archivist]

I was trying to calculate a resource grid and I got this error: "CZooming Grid-Unexpected exception in fortran code". Can you help me?

Thank you in advance.

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This error is arising deep in the orographic interpretation code, and it's not possible to say exactly why. In WAsP 9 & 10, we can't even trap the error and explain it properly on your machine.



My first suggestion is that you use the WAsP Map Editor to check the map for errors.



Do you have any idea where in the grid the problem happens? If so, you could set up a reference site or turbine site at that exact location and try doing the calculation again. This might provide some insight to the cause.



If you don't get any clues, then please email waspsupport@risoe.dk and we'll try to help diagnose the problem. Before you do that, please try to reduce it to the smallest and clearest case: chop the map and grid down so that only the area with the problem is included.

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Thank you very much for your answer. Yes, I now the exact coordinates where the error occurs, it is almost in the middle of a lake. I checked again the map with map editor and the only errors are related to the cross-points. I tried to put a tower on the same spot but I got the same error. The same thing when I tried to make a small grid around the area with the problems. Finally, I changed the limits for the resource grid, to eliminate that region and it worked. Thank you again, it must be something wrong in the maps unfortunately I could not find it.

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Glad that you tracked down the problem. If the map editor says the roughness lines are OK, but the WAsP analysis is still causing problems, then it would be interesting for us to see the data. To double-check, you could use Map Editor to remove all orography data and try the site again. You could also clip around the problem site and make a much smaller map: does that also cause an error?



I don't know which version of WAsP you're using, but I remember we did fix a problem like this in the program several years ago (maybe in an early 8.x release)

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[Niels Gylling Mortensen]

This error (also) happens, if WAsP does not find an elevation or roughness contour within 20 km of a site. It will come up with a warning like “CZoomingGrid - Unexpected exception in Fortran code raised at …” – or simply refuse to calculate.

This distance (calculation radius) is governed by one of the parameters in the projects "Edit project configuration…" menu. If you go to "Edit project configuration… / WAsP wind modeling / Max. interpolation radius in BZ model", you can change this radius to, say, 30000 m. Now your sites might calculate. You can also make an elevation/roughness contour in the area where the problem is, e.g. around the offshore wind farm site. The problem can also happen sometimes with undefined lines in the map.