Looks good to me. I took the "subjective" part from how Martin was asking about quality vs status.
-Barna On Tue, Jul 23, 2019 at 2:40 PM Kehoe, Kenneth E. <kke...@ou.edu> wrote: > Barna, > > OK your definition is fine. I suggest one small change, drop the word > subjective. > > status_flag: A variable with the standard name of status_flag contains an > indication of quality or other status of another data variable. The linkage > between the data variable and the variable with the standard_name of > status_flag is achieved using the ancillary_variables attribute. A variable > which contains purely quality information may use the standard_name of > quality_flag. > > Ken > > > On 2019-7-23 15:28, Andrew Barna wrote: > > Ken, > > I think I'm confused by the text of the proposed change to the definition > of status_flag. > > In your proposed change the "quality" wording of the status_flag > definition was dropped. Here is the first sentence of each: > Current: A variable with the standard name of status_flag contains an > indication of quality or other status of another data variable. > Proposed: A variable with the standard name of status_flag contains an > indication of status of another data variable. > > Perhaps the following for "status_flag": > A variable with the standard name of status_flag contains an indication of > quality or other status of another data variable. The linkage between the > data variable and the variable with the standard_name of status_flag is > achieved using the ancillary_variables attribute. *A variable which > contains purely subjective quality information may use the standard_name of > quality_flag.* > > That is, keep the current definition, but also inform of a more > restrictive option. I don't see any way around not reading the > flag_meanings with any of these options. > > -Barna > > > On Tue, Jul 23, 2019 at 1:03 PM Kehoe, Kenneth E. <kke...@ou.edu> wrote: > >> Barna, >> >> I see this as an optional addition to narrow the standard. It does not >> prohibit someone from using status_flag (as a standard_name or a >> standard_name modifier) from a previous convention version >> implementation nor invalidate that use from a previous convention >> version. In your example the use of status_flag is a mixture of state >> and quality. I see this new name as a way to improve things going >> forward. Since the historical WOCE example uses state and quality with >> some additional rules not listed in the CF standard it would be up to >> the user to understand how to use the variable. Without seeing the WOCE >> data I can't make a specific suggestion. >> >> I don't know about any rules regarding a restriction. I think the >> general concept of CF is to set the minimum rules. Additional rules >> applied by another group on top of CF is allowed. For example my >> organization uses additional attributes not defined in CF. I see >> quality_flag as a narrowing of the rules of status_flag not replace it. >> status_flag can still have a mixture of state and quality if the data >> provider prefers to do it that way. quality_flag can only have quality >> information. The determination of what is quality information is >> actually up to the data provider to decide. >> >> Ken >> >> >> >> On 2019-7-23 13:33, Andrew Barna wrote: >> > Ken, >> > >> > Ok I see how this can be useful. Two more questions: >> > * How would you deal with "legacy" flag schemes which mix "status" and >> > "quality" already? I'm thinking of WOCE CTD as an example where "7" >> > means Despiked (a status) and "3" means Questionable measurement (a >> > quality). The way my seagoing group have dealt with both is by having >> > the "quality" override "status" if the quality is anything other than >> > "good", e.g. a questionable measurement which has been despiked gets >> > flag 3. >> > >> > * Are there rules in CF regarding restricting an existing definition? >> > I imagine there are many datasets already using the "status_flag" name >> > as either a stand alone standard name or a standard name modifier. >> > This change seems to be "breaking" in that previously compliant >> > datasets would now have quality information in a purely status field. >> > >> > Thanks >> > -Barna >> > >> > On Tue, Jul 23, 2019 at 10:08 AM Kehoe, Kenneth E. <kke...@ou.edu> >> wrote: >> >> Martin, >> >> >> >> Thanks for your reply. I would prefer to keep the proposal simple. My >> example of a weighted mean was just one I created off the top of my head. I >> don't see it as something to actually look into implementing. >> >> >> >> I need a way to indicate a variable is a quality status field. The >> distinction that the status field only contains quality information is the >> important distinction. The variable indicated with quality_flag will need >> to also use flag_meanings, same as status_flag. Hence my reason for >> choosing quality_flag to follow a similar naming pattern. >> >> >> >> Barna, >> >> >> >> Without a distinction that the entire variable is a quality variable >> the user is forced to parse the flag_meanings to see if the variable >> applies. This would also encourage a data provider to mix quality with >> source or instrument state or something else in the same variable. That >> would be very difficult to understand. >> >> >> >> As Martin points out quality is more subjective than other status >> information. A user may need to choose what parts of the quality variable >> to apply. I would prefer we not conflate absolute information with >> subjective information. But we need a way to distinguish the variable >> contains absolute information vs a variable that contains more subjective >> information. >> >> >> >> To expand on Martin's example imagine a profiling instrument that has >> a shutter to protect the laser from rain. The laser will always send out >> pulses and the receiver will always be on receiving the return from laser >> pulse. To know when the shutter is in the open state where the instrument >> is profiling we would use a state variable with a simple flag_values method. >> >> >> >> short shutter (time) >> >> shutter:long_name = "Shutter state" >> >> shutter:units = '1' >> >> shutter:flag_values = 0, 1 >> >> shutter:flag_meanings = "closed open" >> >> shutter:standard_name = "status_flag" >> >> >> >> This variable is just indicating the position of the shutter. There is >> no ambiguity with it's use. If a user wants to use the data for atmospheric >> reasons they should filter to only use data where profiling. In fact we can >> implement this variable into our code by only using data where shutter is >> set to open. >> >> >> >> Here is an example of more subjective quality variable. >> >> >> >> short quality_variable (time) >> >> quality_variable:long_name = "Quality variable for linked data >> variable" >> >> quality_variable:units = '1' >> >> quality_variable:flag_masks= 1, 2, 4, 8, 16, 32 >> >> quality_variable:flag_meanings = "Shutter_not_open >> >> Laser_below_80_percent_power >> >> Laser_below_60_percent_power >> >> Laser_below_40_percent_power >> >> Bird_poop_may_be_on_sensor >> >> Bird_poop_is_on_sensor" >> >> quality_variable:flag_meanings = "Bad Suspect Suspect Bad Suspect >> Bad" >> >> quality_variable:standard_name = "quality_flag" >> >> >> >> In this example there are three indications when the laser is less >> than 100%. It would be up to the user to decide what percentage is the >> limit where they do not want to use the data. This is more subjective and >> dependent on the research techniques to determine if the issue a problem or >> not. It is also up to the user to determine if the chance of bird poop on >> the sensor is an issue or if they are OK with the risk of using the data. >> And to be nice to the user we have also pulled in information from the >> shutter variable so the user can decided to only use the quality_variable >> instead of using both shutter and quality_variable. This is up to the data >> provider to decide. Some providers see the state of the shutter as quality >> information, some would not. There is no requirements put on the quality >> variable as to how it is used. It is just a quality information variable >> following the same rules as a CF state variable. >> >> >> >> I have also included an attribute that I am not currently proposing >> called flag_assessment. This is a subjective statement from the data >> provider on their opinion of the quality of the data. A user can search for >> the word "Bad" and then exclude only that data from analysis where the >> mask is set. This would take all the guess work of quality away from the >> user if they decided to take the opinion of the data provider. I'm not >> currently proposing the addition of flag_meanings, this is just an example >> of how quality can be expanded to be more simple for a user but not take >> away the user's ability to make their own decision. Everyone has strong >> opinions on quality of data. >> >> >> >> Thanks, >> >> >> >> Ken >> >> >> >> On 2019-7-23 06:50, Martin Juckes - UKRI STFC wrote: >> >> >> >> Dear Ken, >> >> >> >> >> >> thanks for your response to me below. >> >> >> >> >> >> Would it be fair to suggest that "status" should, as far as possible, >> reflect a generic objective classification, with terms such as >> "sensor_nonfunctional" which have a comparable meaning for all datasets, >> while "quality" is a subjective *measure* with a meaning that may from >> dataset to dataset? E.g. if dataset A has a maximum "quality" of 11 and >> dataset B only goes up to 10, it doesn't necessarily imply that dataset A >> is in any sense better and B. >> >> >> >> >> >> If you want to use it in weighted means, perhaps it should be >> "quality_measure" rather than "quality_flag"? With "status_flag" the order >> of integer values does not have any meaning, but with quality perhaps it >> would make more sense have some concept of a sequence of quality settings >> (so that, for example "1" always indicates a quality between "0" and "2" >> within a dataset, but could have different meanings in different datasets). >> Could the quality also be expressed as a floating point number without any >> flag meanings? >> >> >> >> >> >> Responding to a point Barna raised: it is certainly possible to have >> more than one "status_flag" variable, but I don't think it is ideal: if >> information needs to be split across multiple variables we generally like >> to describe the difference between the variables in the standard name or in >> other metadata. In this case, I think there is a good case for using a new >> standard name. >> >> >> >> >> >> regards, >> >> >> >> Martin >> >> >> >> >> >> >> >> >> >> ________________________________ >> >> From: CF-metadata <cf-metadata-boun...@cgd.ucar.edu> on behalf of >> Andrew Barna <aba...@ucsd.edu> >> >> Sent: 23 July 2019 00:23 >> >> To: Kehoe, Kenneth E. >> >> Cc: cf-metadata@cgd.ucar.edu >> >> Subject: Re: [CF-metadata] New standard_name of quality_flag for >> corresponding quality control variables >> >> >> >> Ken, >> >> >> >> I guess, I don't see this proposed change as necessary since the >> >> distinction between the terms "quality" and "status" is really done in >> >> the "flag_meanings" attribute and is basically free form/uncontrolled. >> >> These attributes need to be used by this new name as well. >> >> >> >> Let me rephrase my suggestion/question: >> >> If this proposal is not adopted, but an example of how to use a >> >> variable, with the standard name of "status_flag", to only indicate >> >> data quality is included in the document, would that help? >> >> >> >> -Barna >> >> >> >> On Mon, Jul 22, 2019 at 1:22 PM Kehoe, Kenneth E. <kke...@ou.edu> >> wrote: >> >> >> >> Barna, >> >> >> >> Yes an update to the CF document should follow after the new >> >> standard_name is implemented. I think multiple examples are needed >> since >> >> status_flag covers many different types of state variables. >> >> >> >> Ken >> >> >> >> >> >> >> >> On 2019-7-22 10:35, Andrew Barna wrote: >> >> >> >> Hi Martin, Ken, >> >> >> >> Is there anything wrong with including multiple "status_flag" >> >> variables to capture all separate state you wish? The CF document >> >> unfortunately only includes an example of how to encode the status of >> >> a sensor, but the actual meanings of the flag values are entirely up >> >> to you, and this will not change with this proposal. Perhaps the CF >> >> document would benefit from additional examples (e.g. one that only >> >> shows data quality flags). >> >> >> >> -Barna >> >> >> >> >> >> On Mon, Jul 22, 2019 at 9:04 AM Kehoe, Kenneth E. <kke...@ou.edu> >> wrote: >> >> >> >> Hi Martin, >> >> >> >> I see status encompassing multiple metadata pieces of information. For >> >> example it could be a state of the instrument as it cycles through a >> >> pre-programed routine (Look at calibration target, look at sky, look at >> >> ground, look at second calibration target, repeat...). Or the sources >> of >> >> the inputs for a model where the availability or some other reason >> could >> >> require making a decision on what source(s) to use. For provenance this >> >> source information is important to report on a time step basis. Or the >> >> status could be a data providers method to provide uncertainty >> >> information (I see this as incorrect but some people do see it this >> >> way). Each of these are important metadata but the method of use is >> >> different than a strictly quality variable. A quality variable provides >> >> information indicating if the data should be used or possibly could be >> >> used in a weighted mean method to favor high quality data over low >> >> quality data. The way the metadata is used is different depending on >> the >> >> metadata type. A state of the instrument would be used for sub-setting >> >> calibration vs. data. There is no ambiguity in this as data from a >> >> calibration target is not used in a weather research analysis. But >> >> quality is more subjective and is decided by the data user. If the >> >> quality variable has 20 different quality tests the user would need to >> >> decided if all 20 test results should be used or only a subset. Also, >> >> the code for applying the quality is different than the state of the >> >> instrument view (in my example above). >> >> >> >> It is possible to have a quality test result from the state of the >> >> instrument, but not the other way around (typically). So I need a way >> to >> >> distinguish the two for automated or semi-automated tools. Hence my >> >> point of quality_flag essentially being a subset of status_flag >> >> >> >> Ken >> >> >> >> >> >> >> >> On 2019-7-22 02:57, Martin Juckes - UKRI STFC wrote: >> >> >> >> Dear Ken, >> >> >> >> >> >> Can you expand on the distinction between "quality" and "status"? I >> understand that they are different in principle, but, in order to support >> this new standard name I think we need a clear objective statement of how >> we would want to distinguish between them in CF. >> >> >> >> The conventions section on flags (3.5) mixes the two up ( >> http://cfconventions.org/cf-conventions/cf-conventions.html#flags >> <https://urldefense.proofpoint.com/v2/url?u=http-3A__cfconventions.org_cf-2Dconventions_cf-2Dconventions.html-23flags&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=f8kQJDfPUHt7Yr0QWW9IT5PssWjH9plqdlgx0zbzbmU&s=NVXr_3U_yIRDQSgpD1aJpW7HG3d4-OGt43w08zZQBk8&e=> >> ), so some re-wording of the document would also be needed, >> >> >> >> regards, >> >> Martin >> >> >> >> ________________________________ >> >> From: CF-metadata <cf-metadata-boun...@cgd.ucar.edu> on behalf of >> Kehoe, Kenneth E. <kke...@ou.edu> >> >> Sent: 19 July 2019 06:42 >> >> To: cf-metadata@cgd.ucar.edu >> >> Subject: [CF-metadata] New standard_name of quality_flag for >> corresponding quality control variables >> >> >> >> Dear CF, >> >> >> >> I am proposing a new standard name of "quality_flag" to indicate a >> variable is purely a quality control variable. A quality control variable >> would use flag_values or flag_masks along with flag_meanings to allow >> declaring levels of quality or results from quality indicating tests of the >> data variable. This variable be a subset of the more general "status_flag" >> standard name. Currently the definition of "status_flag" is: >> >> >> >> - A variable with the standard name of status_flag contains an >> indication of quality or other status of another data variable. The linkage >> between the data variable and the variable with the standard_name of >> status_flag is achieved using the ancillary_variables attribute. >> >> >> >> This definition includes a variable used to define the state or other >> status information of a variable and can not be distinguished by standard >> name alone from a state of the instrument, processing decision, source >> information, needed metadata about the data variable or other ancillary >> variable type. Since there is no other way to define a purely quality >> control variable, the use of "status_flag" is too general for strictly >> quality control variables. By having a method to define a variable as >> strictly quality control the results of quality control tests can be >> applied to the data with a software tool based on requests by the user. >> This would not affect current datasets that do use "status_flag" nor >> require a change to the definition outside of the indication that >> "quality_flag" standard name is available and a better use for pure quality >> control variables. >> >> >> >> Proposed addition: >> >> >> >> quality_flag = A variable with the standard name of quality_flag >> contains an indication of quality information of another data variable. The >> linkage between the data variable and the variable or variables with the >> standard_name of quality_flag is achieved using the ancillary_variables >> attribute. >> >> >> >> Proposed change: >> >> >> >> status_flag = A variable with the standard name of status_flag >> contains an indication of status of another data variable. The linkage >> between the data variable and the variable with the standard_name of >> status_flag is achieved using the ancillary_variables attribute. For data >> quality information use quality_flag. >> >> >> >> Thanks, >> >> >> >> Ken >> >> >> >> >> >> >> >> -- >> >> Kenneth E. Kehoe >> >> Research Associate - University of Oklahoma >> >> Cooperative Institute for Mesoscale Meteorological Studies >> >> ARM Climate Research Facility - Data Quality Office >> >> e-mail: kke...@ou.edu<mailto:kke...@ou.edu> | Office: >> 303-497-4754 >> >> >> >> -- >> >> Kenneth E. Kehoe >> >> Research Associate - University of Oklahoma >> >> Cooperative Institute for Mesoscale Meteorological Studies >> >> ARM Climate Research Facility - Data Quality Office >> >> e-mail: kke...@ou.edu | Office: 303-497-4754 >> >> >> >> _______________________________________________ >> >> CF-metadata mailing list >> >> CF-metadata@cgd.ucar.edu >> >> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata >> <https://urldefense.proofpoint.com/v2/url?u=http-3A__mailman.cgd.ucar.edu_mailman_listinfo_cf-2Dmetadata&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=f8kQJDfPUHt7Yr0QWW9IT5PssWjH9plqdlgx0zbzbmU&s=faPyR9aIDWaBnEUvf-Fr_KcFOMNmAbPj4Yt-T5zAkmE&e=> >> >> >> >> -- >> >> Kenneth E. Kehoe >> >> Research Associate - University of Oklahoma >> >> Cooperative Institute for Mesoscale Meteorological Studies >> >> ARM Climate Research Facility - Data Quality Office >> >> e-mail: kke...@ou.edu | Office: 303-497-4754 >> >> >> >> _______________________________________________ >> >> CF-metadata mailing list >> >> CF-metadata@cgd.ucar.edu >> >> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata >> <https://urldefense.proofpoint.com/v2/url?u=http-3A__mailman.cgd.ucar.edu_mailman_listinfo_cf-2Dmetadata&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=f8kQJDfPUHt7Yr0QWW9IT5PssWjH9plqdlgx0zbzbmU&s=faPyR9aIDWaBnEUvf-Fr_KcFOMNmAbPj4Yt-T5zAkmE&e=> >> >> >> >> _______________________________________________ >> >> CF-metadata mailing list >> >> CF-metadata@cgd.ucar.edu >> >> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata >> <https://urldefense.proofpoint.com/v2/url?u=http-3A__mailman.cgd.ucar.edu_mailman_listinfo_cf-2Dmetadata&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=f8kQJDfPUHt7Yr0QWW9IT5PssWjH9plqdlgx0zbzbmU&s=faPyR9aIDWaBnEUvf-Fr_KcFOMNmAbPj4Yt-T5zAkmE&e=> >> >> >> >> >> >> -- >> >> Kenneth E. Kehoe >> >> Research Associate - University of Oklahoma >> >> Cooperative Institute for Mesoscale Meteorological Studies >> >> ARM Climate Research Facility - Data Quality Office >> >> e-mail: kke...@ou.edu | Office: 303-497-4754 >> >> >> >> _______________________________________________ >> >> CF-metadata mailing list >> >> CF-metadata@cgd.ucar.edu >> >> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata >> <https://urldefense.proofpoint.com/v2/url?u=http-3A__mailman.cgd.ucar.edu_mailman_listinfo_cf-2Dmetadata&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=f8kQJDfPUHt7Yr0QWW9IT5PssWjH9plqdlgx0zbzbmU&s=faPyR9aIDWaBnEUvf-Fr_KcFOMNmAbPj4Yt-T5zAkmE&e=> >> >> -- >> Kenneth E. Kehoe >> Research Associate - University of Oklahoma >> Cooperative Institute for Mesoscale Meteorological Studies >> ARM Climate Research Facility - Data Quality Office >> e-mail: kke...@ou.edu | Office: 303-497-4754 >> >> _______________________________________________ >> CF-metadata mailing list >> CF-metadata@cgd.ucar.edu >> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata >> <https://urldefense.proofpoint.com/v2/url?u=http-3A__mailman.cgd.ucar.edu_mailman_listinfo_cf-2Dmetadata&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=f8kQJDfPUHt7Yr0QWW9IT5PssWjH9plqdlgx0zbzbmU&s=faPyR9aIDWaBnEUvf-Fr_KcFOMNmAbPj4Yt-T5zAkmE&e=> >> > > -- > Kenneth E. Kehoe > Research Associate - University of Oklahoma > Cooperative Institute for Mesoscale Meteorological Studies > ARM Climate Research Facility - Data Quality Office > e-mail: kke...@ou.edu | Office: 303-497-4754 > > _______________________________________________ > CF-metadata mailing list > CF-metadata@cgd.ucar.edu > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata >
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