>From the QARTOD meetings I attended and the vocabularies in our repository, >I'm confident the oceanographic community uses a lot more QC flag approaches >than listed so far. So it is safe to say that there is no single approach.
Still, the approaches from Randy and Roy certainly are accepted by a whole lot of folks. If that meets your definition of "the generally accepted approach", you're good to go. John On Aug 24, 2012, at 00:27, andrew walsh wrote: > Randy, > > The oceanographic community uses a set of integer QC flags (0 to 9) > See document http://www.nodc.noaa.gov/GTSPP/document/qcmans/MG22rev1.pdf > and section 2 'Quality Flagging'. > > One of the flags is for a 'missing value' = 9. Would that suit your fill > value case? > > A netCDF sample in CDL is: > > double TEMP(TIME, DEPTH, LATITUDE, LONGITUDE) ; > TEMP:standard_name = "sea_water_temperature" ; > TEMP:units = "Celsius" ; > TEMP:_FillValue = -99.99 ; > TEMP:valid_min = -2. ; > TEMP:valid_max = 40. ; > TEMP:quality_control_set = 1. ; > TEMP:ancillary_variables = "TEMP_quality_control" ; > byte TEMP_quality_control(TIME, DEPTH, LATITUDE, LONGITUDE) ; > TEMP_quality_control:long_name = "quality control flag for temperature" ; > TEMP_quality_control:standard_name = "sea_water_temperature status_flag" ; > TEMP_quality_control:quality_control_convention = "IMOS standard using IODE > flags" ; > TEMP_quality_control:_FillValue = -9b ; > TEMP_quality_control:valid_min = 0 ; > TEMP_quality_control:valid_max = 9 ; > TEMP_quality_control:flag_values = 0b, 1b, 2b, 3b, 4b, 5b, 6b, 7b, 8b, 9b ; > TEMP_quality_control:flag_meanings = "no_qc_performed good_data > probably_good_data bad_data_that_are_potentially_correctable bad_data > value_changed not_used not_used interpolated_values missing_values" ; > > HTH, > > Andrew Walsh > > ----- Original Message ----- From: "Randy Horne" <rho...@excaliburlabs.com> > To: <cf-metadata@cgd.ucar.edu> > Cc: <aschu...@harris.com>; <rhorn...@harris.com>; <ekenn...@aer.com> > Sent: Friday, August 24, 2012 4:37 AM > Subject: [CF-metadata] Quality flag values for missing data > > >> >> What is the "generally accepted" approach for how a specific quality flag >> value should be assigned for a corresponding data value (in the >> corresponding data variable) that has a _FillValue ? >> >> Is it sufficient that, because the data variable value is _FillValue, the >> corresponding quality flag value can be undefined ? >> >> >> >> ..............End of Message ...............................--> >> >> >> >> >> >> _______________________________________________ >> CF-metadata mailing list >> CF-metadata@cgd.ucar.edu >> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata >> > > _______________________________________________ > CF-metadata mailing list > CF-metadata@cgd.ucar.edu > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata > ---------------- John Graybeal <mailto:jgrayb...@ucsd.edu> phone: 858-534-2162 Product Manager Ocean Observatories Initiative Cyberinfrastructure Project: http://ci.oceanobservatories.org Marine Metadata Interoperability Project: http://marinemetadata.org _______________________________________________ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
