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[netCDF #QCI-275305]: reading netcdf data of type BYTE

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  • Subject: [netCDF #QCI-275305]: reading netcdf data of type BYTE
  • Date: Wed, 16 Oct 2013 15:55:12 -0600
Hi Rachel,

> I am having a lot of trouble reading netcdf variables with the data type
> BYTE.  For example, I am trying to read flag values where each byte is
> given a specific reason for being flagged.  I understand that variable data
> should be an 8 bit number of zeros and ones, but the Fortran 90 compiler
> and system I use apparently only reads in signed integers from -128 to 127.
> 
> Are there some netcdf commands I could use to convert this to something I
> can understand?

Try transforming the values with something like

  if(ival < 0) ival = ival + 256

That transforms the range of signed integers between -128 to 127 into the 
unsigned integers 0 to 255 in a way that preserves the bits for bit flags.

NetCDF-4 explicitly supports unsigned bytes with the type nf90_ubyte, but
the above trick may let you deal with signed bytes as if they were unsigned.

--Russ

Russ Rew                                         UCAR Unidata Program
address@hidden                      http://www.unidata.ucar.edu



Ticket Details
===================
Ticket ID: QCI-275305
Department: Support netCDF
Priority: Normal
Status: Closed