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nmangue / NGrib

NGrib is a .NET library to read GRIB (GRid in Binary) files. GRIB is a gridded data standard from WMO (World Meteorological Organisation) and is used by many meteorological organisation. Fork of GribCS.
GNU Lesser General Public License v3.0
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Grib1Reader ReadRecordRawData only returning 0 values #9

Closed da-br closed 11 months ago

da-br commented 11 months ago

Hello again 😄 ,

Let me preface this by saying I am new to Grib files in general.

When calling ReadRecordRawData on a grib1 file I only retrieve values = 0. I have worked my way through the library code a little and can see Brib1BinaryDataSection.isConstant = true which means the number of bits per value is 0 and therefore returning the refValue (0 in this case)

I can use the grib1 file in the test folder which does return values. I assume it must be the files I am using

When opening the file in Panoply some of the values are displayed as NaN. Not sure if this will have any affect.

image

I am not sure I can attach the file being used, I will find out and attach it if I can.

Any help would be appreciated.

Latest version of NGrib Windows DotNet 472

nmangue commented 11 months ago

Hello !

It could be a bug or an unsupported format. Data can be serialized in many different way in a grib file. To be able to help you, I need access to the file. If you can't post it publicly, you could directly send it to me.

da-br commented 11 months ago

After a bit of digging again, I have answered my own question.

There was a BMS section in the file that was being skipped. I have added support for this in the linked PR. However, I do not know if this was done for a specific reason.

Thanks 😀