Quality control coding: Difference between revisions

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{| class=wikitable style=height:14em
{| class="wikitable"
|-
|-
! Flag !! Meaning !! Comment
! Flag
! Meaning
! Comment
|-
|-
| 0|| unknown || No QC was performed.
| 0
|-
| unknown
| 1 || good data  || All QC tests passed.
| No QC was performed.
|-
|-
| 2 || probably good data || Data have failed one or more QC tests but detailed examination after processing (e.g. by visual examination) suggests data is good.
| 1
|-  
| good data
| 3 || potentially correctable bad data || These data are not to be used without scientific correction or re-calibration (e.g. uncertain shear sensor sensitivity).
| All QC tests passed.
|-  
|-
| 4 || bad data || Data have failed one or more tests.  
| 2
|-  
| probably good data
| 5 || - || Not used
| Data have failed one or more QC tests but detailed examination after processing (e.g. by visual examination) suggests data is good.
|-  
|-
| 6 || - || Not used  
| 3
|-  
| potentially correctable bad data
| 7 || nominal value || Data were not observed but reported (e.g. instrument target depth.).  
| These data are not to be used without scientific correction or re-calibration (e.g. uncertain shear sensor sensitivity).
|-  
|-
| 8 || interpolated value || Missing data may be interpolated from neighboring data in space or time.  
| 4
|-  
| bad data
| 9 || missing value || This is a fill value  
| Data have failed one or more tests.
|-
| 5
| -
| Not used
|-
| 6
| -
| Not used
|-
| 7
| nominal value
| Data were not observed but reported (e.g. instrument target depth.).
|-
| 8
| interpolated value
| Missing data may be interpolated from neighboring data in space or time.
|-
| 9
| missing value
| This is a fill value
|}
|}



Revision as of 18:20, 27 September 2021

Quality control coding

We suggest to follow Ocean Sites for quailty control (QC) coding. The flagging scheme is mostly compatible with the primary level flagging recommended by Intergovernmental Oceanographic Commission of UNESCO (2013).


Flag Meaning Comment
0 unknown No QC was performed.
1 good data All QC tests passed.
2 probably good data Data have failed one or more QC tests but detailed examination after processing (e.g. by visual examination) suggests data is good.
3 potentially correctable bad data These data are not to be used without scientific correction or re-calibration (e.g. uncertain shear sensor sensitivity).
4 bad data Data have failed one or more tests.
5 - Not used
6 - Not used
7 nominal value Data were not observed but reported (e.g. instrument target depth.).
8 interpolated value Missing data may be interpolated from neighboring data in space or time.
9 missing value This is a fill value


Climate and Forecast Metadata Convention (CF) requires that QC flags carry attributes. In netCDF (Network Common Data Form) data files, the following information for quality control flagging should be provided for each data variable <PARAM>.

<PARAM>_QC
<PARAM>_QC:long_name = “quality flag of <PARAM>”;
<PARAM>_QC:conventions = “OceanSITES QC Flags”;
<PARAM>_QC:flag_values = 0, 1, 2, 3, 4, 7, 8, 9;
<PARAM>_QC:flag_meanings = “0:unknown 1:good_data 2:probably_good_data 3:potentially_correctable_bad_data 4:bad_data 7:nominal_value 8:interpolated_value 9:missing_value”