- tdwg - lists.tdwg.org

Re: Standards for date / time values?
by Roger Hyam 27 Feb '06

27 Feb '06

Who is using data scored like this - actually searching on and analyzing data that was scored to 'summer', 'autumn', 'early 19th century' This thread seems to be a great deal about how to capture data from various historic sources but what are the *use cases* for exploitation of it? What is the cost benefit analysis of doing more than Stan suggested above, /a priori,/ in the hope that it will be more useful than just capturing a string plus a year that can analyzed later if they ever need to be - which they might not. Just some thoughts, Roger Michael Lee wrote: > Hello all, > > It seems to me that the VerbatimDate/EarliestDate/LatestDate are > helpful, but combine two separate issues: > > 1) duration of the event spanning more than one date/time unit > 2) error associated with the date. > > Is the distinction useful? Probably depends on your application of the > date. > > To handle these, VegBank uses three fields: > > startDateTime > stopDateTime > dateTimeAccuracy > (note that there is NO verbatimDate) > > StartDateTime is most precise known date/time for the beginning of an > event (in our case an observation of a vegetation plot) and the > EndDateTime is the end date/time (which could have the same value). > DateTimeAccuracy is a string with a list of values ranging from 1 second > to 1 day to 1 year to 5,10 years, etc. > > start and stop deal with issue #1 above, duration (potentially) exceeding > usual date description precision. > > The accuracy field deals with isue #2 above, error or uncertainty > regarding the dates. It is this accuracy field that seems to be missing > from this discussion thus far. > > As far as time zones go, error on the order of hours isn't TOO important > to us, so we don't worry about it too much. But I think what we're > aiming > to do is to store the date/time according to UTC. This means that to > reconstruct what time the person saw something, the original time zone > and > Daylight Savings Time would need to be known, but this isn't crucial to > us, either. > > I like Lynn's list of weird dates, so I'll throw in what we'd do with > them > (this of course being "interpreted" but as Rich says, that's almost > always > the case): > > PRE-1975 > Start:null ; End: 01-JAN-1975 ; Accuracy: null or possibly a large value > post-1992 > Start: 01-Jan-1992; End:null ; Accuracy: null or possibly a large value > summer 2001 > Start: 15-JUL-2001; End:15-JUL-2001 ; Accuracy: 1.5 months > Mid-1990s > Start: 01-JUL-1995; End: 01-JUL-1995 ; Accuracy: 2 years > late 1950's > Start: 01-JAN-1958; End: 01-JAN-1958; Accuracy: 2.5 years > Circa 1941 > Start: 01-JUL-1941; End:01-JUL-1941; Accuracy: 6 months > Early 1990s > Start: 01-JAN-1992; End:01-JAN-1992; Accuracy: 2 years > > Except for the "pre-Date" and "post-Date" I have assumed a relatively > short duration. But this is interpreted. The problems with this > approach > I see are: > 1) accuracy for start and stop dates could be different > 2) accuracy is not a black and white idea. It's often more of a > gradient. Seems > illogical to specify 10 years as accuracy in the first 2 examples, as the > dates could be much more than 10 years away. > 3) a closed list on accuracy seems to force you into decisions you don't > want to make. But an open field is problematic as you might not > always be > able to interpret it. Perhaps 2 fields: DateAccuracyNumeric and > DateAccuracyUnits would help, or you could require the units to be > converted to years, with very tiny accuracies being really small decimal > numbers. > 4) Doesn't tackle issues of 2 dates (May or Sept of 1995) all that well. > > > But it seems flexible enough for our purposes. I wasn't part of the team > that designed it, so I'm not sure what alternatives they considered and > for what reasons they rejected any alternatives they considered. > > cheers, > michael > > > ---------------------------- > Michael Lee > VegBank Project Manager > http://www.vegbank.org > ---------------------------- > > On Mon, 27 Feb 2006, Hannu Saarenmaa wrote: > >> In my understanding the "Not interpreted" case would be just a text >> string "DateTimeSourceText", repeating whatever is written in the label >> about the dates and times. This can be useful if questions arise of the >> interpretation. >> >> Btw., isn't he name of the element "EarliestDateCollected" in Darwin >> Core v.1.4 proposal a bit misleading as it really is >> "EarliestDateTimeCollected"? >> >> Hannu >> >> Richard Pyle wrote: >> >>> RE: CollectingDatesInterpreted >>> When would this field *not* be set to true? >>> >> > -- ------------------------------------- Roger Hyam Technical Architect Taxonomic Databases Working Group ------------------------------------- http://www.tdwg.org roger(a)tdwg.org +44 1578 722782 -------------------------------------

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Re: Standards for date / time values?
by Hannu Saarenmaa 27 Feb '06

27 Feb '06

In my understanding the "Not interpreted" case would be just a text string "DateTimeSourceText", repeating whatever is written in the label about the dates and times. This can be useful if questions arise of the interpretation. Btw., isn't he name of the element "EarliestDateCollected" in Darwin Core v.1.4 proposal a bit misleading as it really is "EarliestDateTimeCollected"? Hannu Richard Pyle wrote: >RE: CollectingDatesInterpreted >When would this field *not* be set to true? >

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Re: Standards for date / time values?
by Michael Lee 27 Feb '06

27 Feb '06

Hello all, It seems to me that the VerbatimDate/EarliestDate/LatestDate are helpful, but combine two separate issues: 1) duration of the event spanning more than one date/time unit 2) error associated with the date. Is the distinction useful? Probably depends on your application of the date. To handle these, VegBank uses three fields: startDateTime stopDateTime dateTimeAccuracy (note that there is NO verbatimDate) StartDateTime is most precise known date/time for the beginning of an event (in our case an observation of a vegetation plot) and the EndDateTime is the end date/time (which could have the same value). DateTimeAccuracy is a string with a list of values ranging from 1 second to 1 day to 1 year to 5,10 years, etc. start and stop deal with issue #1 above, duration (potentially) exceeding usual date description precision. The accuracy field deals with isue #2 above, error or uncertainty regarding the dates. It is this accuracy field that seems to be missing from this discussion thus far. As far as time zones go, error on the order of hours isn't TOO important to us, so we don't worry about it too much. But I think what we're aiming to do is to store the date/time according to UTC. This means that to reconstruct what time the person saw something, the original time zone and Daylight Savings Time would need to be known, but this isn't crucial to us, either. I like Lynn's list of weird dates, so I'll throw in what we'd do with them (this of course being "interpreted" but as Rich says, that's almost always the case): PRE-1975 Start:null ; End: 01-JAN-1975 ; Accuracy: null or possibly a large value post-1992 Start: 01-Jan-1992; End:null ; Accuracy: null or possibly a large value summer 2001 Start: 15-JUL-2001; End:15-JUL-2001 ; Accuracy: 1.5 months Mid-1990s Start: 01-JUL-1995; End: 01-JUL-1995 ; Accuracy: 2 years late 1950's Start: 01-JAN-1958; End: 01-JAN-1958; Accuracy: 2.5 years Circa 1941 Start: 01-JUL-1941; End:01-JUL-1941; Accuracy: 6 months Early 1990s Start: 01-JAN-1992; End:01-JAN-1992; Accuracy: 2 years Except for the "pre-Date" and "post-Date" I have assumed a relatively short duration. But this is interpreted. The problems with this approach I see are: 1) accuracy for start and stop dates could be different 2) accuracy is not a black and white idea. It's often more of a gradient. Seems illogical to specify 10 years as accuracy in the first 2 examples, as the dates could be much more than 10 years away. 3) a closed list on accuracy seems to force you into decisions you don't want to make. But an open field is problematic as you might not always be able to interpret it. Perhaps 2 fields: DateAccuracyNumeric and DateAccuracyUnits would help, or you could require the units to be converted to years, with very tiny accuracies being really small decimal numbers. 4) Doesn't tackle issues of 2 dates (May or Sept of 1995) all that well. But it seems flexible enough for our purposes. I wasn't part of the team that designed it, so I'm not sure what alternatives they considered and for what reasons they rejected any alternatives they considered. cheers, michael ---------------------------- Michael Lee VegBank Project Manager http://www.vegbank.org ---------------------------- On Mon, 27 Feb 2006, Hannu Saarenmaa wrote: > In my understanding the "Not interpreted" case would be just a text > string "DateTimeSourceText", repeating whatever is written in the label > about the dates and times. This can be useful if questions arise of the > interpretation. > > Btw., isn't he name of the element "EarliestDateCollected" in Darwin > Core v.1.4 proposal a bit misleading as it really is > "EarliestDateTimeCollected"? > > Hannu > > Richard Pyle wrote: > >> RE: CollectingDatesInterpreted >> When would this field *not* be set to true? >> >

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Re: Standards for date / time values?
by John R. WIECZOREK 24 Feb '06

24 Feb '06

I concur with Richard on the sufficiency of the three fields, and prefer to err on the side of simplicity for the DwC. On 2/24/06, Richard Pyle <deepreef(a)bishopmuseum.org> wrote: > > RE: CollectingDatesInterpreted > When would this field *not* be set to true? In other words, what is the > threshold for "interpreted", in terms of populating EarliestCollectingDate > and LatestCollectingDate? > > At one extreme, we have a VerbatimDateTime of "12 January 2005, 13:34:15 > local time". Not a lot of interpretation needed there (other than > conversion of original documentation format to ASCII/Unicode, and > interpretation of the time zone from the locality data). But conversion > of > "12 January 2005" to > > EarliestCollectingDate: "2005-01-12 00:00:00" > LatestCollectingDate: "2005-01-12 23:59:59" > > ...requires a bit of interpretation. Maybe the time portion could simply > be > omitted; but even still, there is technically *some* interpretation when > converting "January" to "01". > > And the spectrum continues on from there up until, well, stuff that would > be > unambiguously flagged as "interpreted". > > My point is, there should be some sort of guideline as to when to set > CollectingDatesInterpreted true; i.e., what threshold of interpretation > triggers that field. If such a guideline already exists, then I apologize > for missing it. > > Personally, I don't think CollectingDatesInterpreted is necessary, really, > because I have always regarded my equivalents of EarliestCollectingDate > and > LatestCollectingDate as interpreted. > > RE: Lynn's examples below. > I wrestled with these issues (and more) a number of years ago. Other > examples include "Summer; year unknown" (important for seasonal species), > and multiple (non-contiguous) date ranges: "May or August, 2004" -- among > others. > > In addition to the equivalents of VerbatimDateTime, > EarliestCollectingDate, > LatestCollectingDate; I had a controlled-vocabulary field called > "DateRangeQualifier", which had an enumerated list of options tied to > interpretation logic (e.g., "continuous range", "discontinuous range", > "unknown point", "either/or", etc.; as well as sub-range qualifiers like > "Summer"). I modelled it after an analogous field I use for interpreting > paired or multiple georef coordinates (e.g., "transect" vs. "bounding > box"; > "polygon" vs. "linear"). This DateRangeQualifier approach ended up being > too > cumbersome to implement -- only because I was too lazy, and the number of > cases that benefited from it (i.e., allowed computer logic to be applied, > independent of a human reading of the VerbatimDateTime value) was low. > > The three fields > VerbatimDateTime/EarliestCollectingDate/LatestCollectingDate will give you > 90% of the value 90% of the time (at least for the specimen/observation > data > that I deal with). I wonder if DWC really needs more precision capability > than that.... > > Rich > > Richard L. Pyle, PhD > Database Coordinator for Natural Sciences > Department of Natural Sciences, Bishop Museum > 1525 Bernice St., Honolulu, HI 96817 > Ph: (808)848-4115, Fax: (808)847-8252 > email: deepreef(a)bishopmuseum.org > http://hbs.bishopmuseum.org/staff/pylerichard.html > > > > -----Original Message----- > From: Taxonomic Databases Working Group List > [mailto:TDWG@LISTSERV.NHM.KU.EDU]On Behalf Of Lynn Kutner > Sent: Thursday, February 23, 2006 5:26 PM > To: TDWG(a)LISTSERV.NHM.KU.EDU > Subject: Re: Standards for date / time values? > > > Hi Stan and all - > > Yes, I am thinking about dates in the context of the observation / > monitoring schema. > > Here are some of the types of dates that I've seen in just the data from > the > NatureServe member programs based on either lack of available information > or > interesting data collection situations. > > 1) partial dates (only have the year or year-month) - definitely > accommodated by the ISO 8601 format > > 2) vague dates - for these I suppose you'd use ISO 8601 in > EarliestCollectingDate / LatestCollectingDate, VerbatimDateTime, and the > CollectingDatesInterpreted flag ? > > PRE-1975 > post-1992 > summer 2001 > Mid-1990s > late 1950's > Circa 1941 > Early 1990s > > 3) a range of dates indicating that collection occurred on a specific date > sometime between those two limits and you're not sure when (example: > Observations / collections from pitfall traps may have date ranges > associated with them rather than a single date. For instance, you can have > dates of collection of 19Dec 2004 to 23Jan 2005 and the specimen was from > some unknown specific date in that rage), > > 4) continuous data collection over a period of time (some sort of sensor) > > 5) information collected on one of two possible dates (one or the other is > correct, it's not a range) (example: aerial surveys flown on either May 27 > or June 04, 1999). > > It seems that EarliestCollectingDate / LatestCollectingDate could be used > for #3, #4, and #5 - but is there a way to differentiate between these as > actually being very different types of dates? Would those distinctions > just > be communicated using the VerbatimDateTime? > > Of course for all of these examples the fallback would be to use the > VerbatimDateTime, but it would be ideal to have as much as possible of the > date information in field(s) that can be queried and analyzed > > Thank you for your thoughts and help. > > Lynn > > > > Lynn Kutner > NatureServe > www.natureserve.org > (303) 541-0360 > lynn_kutner(a)natureserve.org > > > > From: Blum, Stan [mailto:sblum@calacademy.org] > Sent: Thu 2/23/2006 6:41 PM > To: Lynn Kutner; TDWG(a)LISTSERV.NHM.KU.EDU > Subject: RE: Standards for date / time values? > > > Hi Lynn, > > Context is everything, so I'm going to assume you are talking about > date/time representations in the observation and monitoring schema(s) that > you are developing. The thinking in the collections community has gone > something along the lines of this: > > Concept: the date-time of a collecting event [= recording-event, > gathering-event] -- i.e., when one or more organisms were collected or > observed -- expressed in the common Gregorian calendar, in local time. > > Requirements: > > 1 - express the data/time exactly as it was recorded > 2 - retreive records by date/time ranges (date-time greater than X and/or > less than Y) > 3 - accommodate date-times of varying precision, including explicit > date-time ranges (specifying a duration) > 4 - support seasonal (time of year) queries > > These requirements can be met by the following fields: > > VerbatimDateTime > EarliestDateCollected > LatestDateCollected > CollectingDatesInterpreted > DayOfYear > > As John Wieczorek noted, the ISO 8601 format accommodates varying degrees > of > precision. Using a "verbatim date-time" [text string] is as good as you > can > do to satisfy the first requirement, short of scanning field notes or > voice > recordings. The earliest and latest dates support the recording of > explicit > ranges as well as interpreted ranges, which could be used to make "Summer > of > 1952" retrievable. The CollectingDatesInterpreted field would be a > boolean > field, set as true when the earliest and latest dates represent > interpretations rather than an explicit range. The "DayOfYear" field is a > compromise that we've offered as a simple way to support queries involving > seasonal (annual) cycles; e.g., collected in the northern summer, > regardless > of year. But it can be argued that day of year is derivable from the > other > fields (unless year is unknown), and that it doesn't accommodate explicit > ranges. > > A bit more documentation is needed to address the odd cases (What do I do > when ...?), but these five fields will support a lot of the data exchange > needed for this concept. These fields are not intended to handle the > dating > of localities in paleontology, nor are they intended to handle named > periods > that are used in cultural collections (e.g., Iron Age, Victorian). > > ABCD uses a few more fields to handle the concept, > http://ww3.bgbm.org/abcddocs/AbcdConcepts but some of these (date, time, > and time zone) are handled by the ISO format, except when the larger units > are unkown; .e.g., the year is unknown, but the day is [ June 16 ]; or the > date is unknown, but the time is [ 14:00-15:30 ]. > > AbcdConcept0860 /DataSets/DataSet/Units/Unit/Gathering/DateTime > AbcdConcept0861 /DataSets/DataSet/Units/Unit/Gathering/DateTime/DateText > AbcdConcept0862 /DataSets/DataSet/Units/Unit/Gathering/DateTime/TimeZone > AbcdConcept0863 > /DataSets/DataSet/Units/Unit/Gathering/DateTime/ISODateTimeBegin > AbcdConcept0864 > /DataSets/DataSet/Units/Unit/Gathering/DateTime/DayNumberBegin > AbcdConcept0865 > /DataSets/DataSet/Units/Unit/Gathering/DateTime/TimeOfDayBegin > AbcdConcept0866 > /DataSets/DataSet/Units/Unit/Gathering/DateTime/ISODateTimeEnd > AbcdConcept0867 > /DataSets/DataSet/Units/Unit/Gathering/DateTime/DayNumberEnd > AbcdConcept0868 > /DataSets/DataSet/Units/Unit/Gathering/DateTime/TimeOfDayEnd > AbcdConcept0869 > /DataSets/DataSet/Units/Unit/Gathering/DateTime/PeriodExplicit > The ABCD fields pretty much cover the entire concept space. One could > argue > whether time-zone is relevant to the description of biological phenomena, > but we do know that ship trawls do cross time-zones (including the > date-line), and that daylight savings time could stretch or compress some > nocturnal collecting events if their durations were calculated too simply. > > To some extent these arguments are still going on, so analyze your > requirements and your data, then state your position. ;-) > > Cheers, > > -Stan > Stanley D. Blum, Ph.D. > Research Information Manager > California Academy of Sciences > 875 Howard St. > San Francisco, CA > +1 (415) 321-8183 > > > -----Original Message----- > From: Taxonomic Databases Working Group List > [mailto:TDWG@LISTSERV.NHM.KU.EDU] On Behalf Of Lynn Kutner > Sent: Thursday, February 23, 2006 9:12 AM > To: TDWG(a)LISTSERV.NHM.KU.EDU > Subject: Standards for date / time values? > > > Hi - > I'm working with a suite of date attributes that can include a combination > of precise dates, imprecise dates, and ranges of dates (and the same types > of time values). We'd like to follow existing standards. If this sort of > date / time standard exists, I'd appreciate leads to the appropriate > resources. > Thank you for your help - > Lynn > > > Lynn Kutner > Data Management Coordinator > NatureServe > Email: lynn_kutner(a)natureserve.org > Phone: (303) 541-0360 > www.natureserve.org >

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Re: Standards for date / time values?
by Patricia Koleff Osorio 24 Feb '06

24 Feb '06

We should be clear on format for Early and Latest CollectionDate, meaning to store data as DDMMYYYY There are some old specimens missing the day or even the month (and only have years, and even not the complete year, only the like 79) I think that time hour should be another field, noting that must be refered to the locality Regards Patricia Koleff At 12:00 a.m. 24/02/2006 -1000, Richard Pyle wrote: >RE: CollectingDatesInterpreted >When would this field *not* be set to true? In other words, what is the >threshold for "interpreted", in terms of populating EarliestCollectingDate >and LatestCollectingDate? > >At one extreme, we have a VerbatimDateTime of "12 January 2005, 13:34:15 >local time". Not a lot of interpretation needed there (other than >conversion of original documentation format to ASCII/Unicode, and >interpretation of the time zone from the locality data). But conversion of >"12 January 2005" to > >EarliestCollectingDate: "2005-01-12 00:00:00" >LatestCollectingDate: "2005-01-12 23:59:59" > >...requires a bit of interpretation. Maybe the time portion could simply be >omitted; but even still, there is technically *some* interpretation when >converting "January" to "01". > >And the spectrum continues on from there up until, well, stuff that would be >unambiguously flagged as "interpreted". > >My point is, there should be some sort of guideline as to when to set >CollectingDatesInterpreted true; i.e., what threshold of interpretation >triggers that field. If such a guideline already exists, then I apologize >for missing it. > >Personally, I don't think CollectingDatesInterpreted is necessary, really, >because I have always regarded my equivalents of EarliestCollectingDate and >LatestCollectingDate as interpreted. > >RE: Lynn's examples below. >I wrestled with these issues (and more) a number of years ago. Other >examples include "Summer; year unknown" (important for seasonal species), >and multiple (non-contiguous) date ranges: "May or August, 2004" -- among >others. > >In addition to the equivalents of VerbatimDateTime, EarliestCollectingDate, >LatestCollectingDate; I had a controlled-vocabulary field called >"DateRangeQualifier", which had an enumerated list of options tied to >interpretation logic (e.g., "continuous range", "discontinuous range", >"unknown point", "either/or", etc.; as well as sub-range qualifiers like >"Summer"). I modelled it after an analogous field I use for interpreting >paired or multiple georef coordinates (e.g., "transect" vs. "bounding box"; >"polygon" vs. "linear"). This DateRangeQualifier approach ended up being too >cumbersome to implement -- only because I was too lazy, and the number of >cases that benefited from it (i.e., allowed computer logic to be applied, >independent of a human reading of the VerbatimDateTime value) was low. > >The three fields >VerbatimDateTime/EarliestCollectingDate/LatestCollectingDate will give you >90% of the value 90% of the time (at least for the specimen/observation data >that I deal with). I wonder if DWC really needs more precision capability >than that.... > >Rich > >Richard L. Pyle, PhD >Database Coordinator for Natural Sciences >Department of Natural Sciences, Bishop Museum >1525 Bernice St., Honolulu, HI 96817 >Ph: (808)848-4115, Fax: (808)847-8252 >email: deepreef(a)bishopmuseum.org >http://hbs.bishopmuseum.org/staff/pylerichard.html > > > >-----Original Message----- >From: Taxonomic Databases Working Group List >[mailto:TDWG@LISTSERV.NHM.KU.EDU]On Behalf Of Lynn Kutner >Sent: Thursday, February 23, 2006 5:26 PM >To: TDWG(a)LISTSERV.NHM.KU.EDU >Subject: Re: Standards for date / time values? > > >Hi Stan and all - > >Yes, I am thinking about dates in the context of the observation / >monitoring schema. > >Here are some of the types of dates that I've seen in just the data from the >NatureServe member programs based on either lack of available information or >interesting data collection situations. > >1) partial dates (only have the year or year-month) - definitely >accommodated by the ISO 8601 format > >2) vague dates - for these I suppose you'd use ISO 8601 in >EarliestCollectingDate / LatestCollectingDate, VerbatimDateTime, and the >CollectingDatesInterpreted flag ? > >PRE-1975 >post-1992 >summer 2001 >Mid-1990s >late 1950's >Circa 1941 >Early 1990s > >3) a range of dates indicating that collection occurred on a specific date >sometime between those two limits and you're not sure when (example: >Observations / collections from pitfall traps may have date ranges >associated with them rather than a single date. For instance, you can have >dates of collection of 19Dec 2004 to 23Jan 2005 and the specimen was from >some unknown specific date in that rage), > >4) continuous data collection over a period of time (some sort of sensor) > >5) information collected on one of two possible dates (one or the other is >correct, it's not a range) (example: aerial surveys flown on either May 27 >or June 04, 1999). > >It seems that EarliestCollectingDate / LatestCollectingDate could be used >for #3, #4, and #5 - but is there a way to differentiate between these as >actually being very different types of dates? Would those distinctions just >be communicated using the VerbatimDateTime? > >Of course for all of these examples the fallback would be to use the >VerbatimDateTime, but it would be ideal to have as much as possible of the >date information in field(s) that can be queried and analyzed > >Thank you for your thoughts and help. > >Lynn > > > >Lynn Kutner >NatureServe >www.natureserve.org >(303) 541-0360 >lynn_kutner(a)natureserve.org > > > >From: Blum, Stan [mailto:sblum@calacademy.org] >Sent: Thu 2/23/2006 6:41 PM >To: Lynn Kutner; TDWG(a)LISTSERV.NHM.KU.EDU >Subject: RE: Standards for date / time values? > > >Hi Lynn, > >Context is everything, so I'm going to assume you are talking about >date/time representations in the observation and monitoring schema(s) that >you are developing. The thinking in the collections community has gone >something along the lines of this: > >Concept: the date-time of a collecting event [= recording-event, >gathering-event] -- i.e., when one or more organisms were collected or >observed -- expressed in the common Gregorian calendar, in local time. > >Requirements: > >1 - express the data/time exactly as it was recorded >2 - retreive records by date/time ranges (date-time greater than X and/or >less than Y) >3 - accommodate date-times of varying precision, including explicit >date-time ranges (specifying a duration) >4 - support seasonal (time of year) queries > >These requirements can be met by the following fields: > >VerbatimDateTime >EarliestDateCollected >LatestDateCollected >CollectingDatesInterpreted >DayOfYear > >As John Wieczorek noted, the ISO 8601 format accommodates varying degrees of >precision. Using a "verbatim date-time" [text string] is as good as you can >do to satisfy the first requirement, short of scanning field notes or voice >recordings. The earliest and latest dates support the recording of explicit >ranges as well as interpreted ranges, which could be used to make "Summer of >1952" retrievable. The CollectingDatesInterpreted field would be a boolean >field, set as true when the earliest and latest dates represent >interpretations rather than an explicit range. The "DayOfYear" field is a >compromise that we've offered as a simple way to support queries involving >seasonal (annual) cycles; e.g., collected in the northern summer, regardless >of year. But it can be argued that day of year is derivable from the other >fields (unless year is unknown), and that it doesn't accommodate explicit >ranges. > >A bit more documentation is needed to address the odd cases (What do I do >when ...?), but these five fields will support a lot of the data exchange >needed for this concept. These fields are not intended to handle the dating >of localities in paleontology, nor are they intended to handle named periods >that are used in cultural collections (e.g., Iron Age, Victorian). > >ABCD uses a few more fields to handle the concept, >http://ww3.bgbm.org/abcddocs/AbcdConcepts but some of these (date, time, >and time zone) are handled by the ISO format, except when the larger units >are unkown; .e.g., the year is unknown, but the day is [ June 16 ]; or the >date is unknown, but the time is [ 14:00-15:30 ]. > >AbcdConcept0860 /DataSets/DataSet/Units/Unit/Gathering/DateTime >AbcdConcept0861 /DataSets/DataSet/Units/Unit/Gathering/DateTime/DateText >AbcdConcept0862 /DataSets/DataSet/Units/Unit/Gathering/DateTime/TimeZone >AbcdConcept0863 >/DataSets/DataSet/Units/Unit/Gathering/DateTime/ISODateTimeBegin >AbcdConcept0864 >/DataSets/DataSet/Units/Unit/Gathering/DateTime/DayNumberBegin >AbcdConcept0865 >/DataSets/DataSet/Units/Unit/Gathering/DateTime/TimeOfDayBegin >AbcdConcept0866 >/DataSets/DataSet/Units/Unit/Gathering/DateTime/ISODateTimeEnd >AbcdConcept0867 >/DataSets/DataSet/Units/Unit/Gathering/DateTime/DayNumberEnd >AbcdConcept0868 >/DataSets/DataSet/Units/Unit/Gathering/DateTime/TimeOfDayEnd >AbcdConcept0869 >/DataSets/DataSet/Units/Unit/Gathering/DateTime/PeriodExplicit >The ABCD fields pretty much cover the entire concept space. One could argue >whether time-zone is relevant to the description of biological phenomena, >but we do know that ship trawls do cross time-zones (including the >date-line), and that daylight savings time could stretch or compress some >nocturnal collecting events if their durations were calculated too simply. > >To some extent these arguments are still going on, so analyze your >requirements and your data, then state your position. ;-) > >Cheers, > >-Stan >Stanley D. Blum, Ph.D. >Research Information Manager >California Academy of Sciences >875 Howard St. >San Francisco, CA >+1 (415) 321-8183 > > >-----Original Message----- >From: Taxonomic Databases Working Group List >[mailto:TDWG@LISTSERV.NHM.KU.EDU] On Behalf Of Lynn Kutner >Sent: Thursday, February 23, 2006 9:12 AM >To: TDWG(a)LISTSERV.NHM.KU.EDU >Subject: Standards for date / time values? > > >Hi - >I'm working with a suite of date attributes that can include a combination >of precise dates, imprecise dates, and ranges of dates (and the same types >of time values). We'd like to follow existing standards. If this sort of >date / time standard exists, I'd appreciate leads to the appropriate >resources. >Thank you for your help - >Lynn > > >Lynn Kutner >Data Management Coordinator >NatureServe >Email: lynn_kutner(a)natureserve.org >Phone: (303) 541-0360 >www.natureserve.org Dra. Patricia Koleff Directora de Análisis y Prioridades CONABIO Comisión Nacional para el Conocimiento y Uso de la Biodiversidad Av. Liga Periferico - Insurgentes Sur 4903 Col. Parques del Pedregal Delegacion Tlalpan 14010 Mexico, D.F. MEXICO Tel. +52 (55) 5528 9105 Fax +52 (55) 5528 9194 www.conabio.gob.mx e-mail: pkoleff(a)xolo.conabio.gob.mx

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Re: Standards for date / time values?
by John R. WIECZOREK 24 Feb '06

24 Feb '06

Patricia, and all, The ISO 8601 standard specifies the format explicitly. The W3C implementation of it is explained at http://www.w3.org/TR/NOTE-datetime. Your point is well taken though, some interpretation of original data (e.g., expanding two-digit years to four digits) will often have to be done to express dates as xsd:dateTime. Can you justify the separation (or addition) of the time fields? It may ease the expression of queries on time independent of date. It may also allow one to express a discrete across a date range (e.g., 17:00 every day in June 2005). This seems like an exceptional case. Is that worth adding two more concepts to accomodate this? John On 2/24/06, Patricia Koleff Osorio <pkoleff(a)xolo.conabio.gob.mx> wrote: > > We should be clear on format for Early and Latest CollectionDate, meaning > to store data as DDMMYYYY > There are some old specimens missing the day or even the month (and only > have years, and even not the complete year, only the like 79) > I think that time hour should be another field, noting that must be > refered > to the locality > Regards > Patricia Koleff > > > At 12:00 a.m. 24/02/2006 -1000, Richard Pyle wrote: > >RE: CollectingDatesInterpreted > >When would this field *not* be set to true? In other words, what is the > >threshold for "interpreted", in terms of populating > EarliestCollectingDate > >and LatestCollectingDate? > > > >At one extreme, we have a VerbatimDateTime of "12 January 2005, 13:34:15 > >local time". Not a lot of interpretation needed there (other than > >conversion of original documentation format to ASCII/Unicode, and > >interpretation of the time zone from the locality data). But conversion > of > >"12 January 2005" to > > > >EarliestCollectingDate: "2005-01-12 00:00:00" > >LatestCollectingDate: "2005-01-12 23:59:59" > > > >...requires a bit of interpretation. Maybe the time portion could simply > be > >omitted; but even still, there is technically *some* interpretation when > >converting "January" to "01". > > > >And the spectrum continues on from there up until, well, stuff that would > be > >unambiguously flagged as "interpreted". > > > >My point is, there should be some sort of guideline as to when to set > >CollectingDatesInterpreted true; i.e., what threshold of interpretation > >triggers that field. If such a guideline already exists, then I apologize > >for missing it. > > > >Personally, I don't think CollectingDatesInterpreted is necessary, > really, > >because I have always regarded my equivalents of EarliestCollectingDate > and > >LatestCollectingDate as interpreted. > > > >RE: Lynn's examples below. > >I wrestled with these issues (and more) a number of years ago. Other > >examples include "Summer; year unknown" (important for seasonal species), > >and multiple (non-contiguous) date ranges: "May or August, 2004" -- among > >others. > > > >In addition to the equivalents of VerbatimDateTime, > EarliestCollectingDate, > >LatestCollectingDate; I had a controlled-vocabulary field called > >"DateRangeQualifier", which had an enumerated list of options tied to > >interpretation logic (e.g., "continuous range", "discontinuous range", > >"unknown point", "either/or", etc.; as well as sub-range qualifiers like > >"Summer"). I modelled it after an analogous field I use for interpreting > >paired or multiple georef coordinates (e.g., "transect" vs. "bounding > box"; > >"polygon" vs. "linear"). This DateRangeQualifier approach ended up being > too > >cumbersome to implement -- only because I was too lazy, and the number of > >cases that benefited from it (i.e., allowed computer logic to be applied, > >independent of a human reading of the VerbatimDateTime value) was low. > > > >The three fields > >VerbatimDateTime/EarliestCollectingDate/LatestCollectingDate will give > you > >90% of the value 90% of the time (at least for the specimen/observation > data > >that I deal with). I wonder if DWC really needs more precision capability > >than that.... > > > >Rich > > > >Richard L. Pyle, PhD > >Database Coordinator for Natural Sciences > >Department of Natural Sciences, Bishop Museum > >1525 Bernice St., Honolulu, HI 96817 > >Ph: (808)848-4115, Fax: (808)847-8252 > >email: deepreef(a)bishopmuseum.org > >http://hbs.bishopmuseum.org/staff/pylerichard.html > > > > > > > >-----Original Message----- > >From: Taxonomic Databases Working Group List > >[mailto:TDWG@LISTSERV.NHM.KU.EDU]On Behalf Of Lynn Kutner > >Sent: Thursday, February 23, 2006 5:26 PM > >To: TDWG(a)LISTSERV.NHM.KU.EDU > >Subject: Re: Standards for date / time values? > > > > > >Hi Stan and all - > > > >Yes, I am thinking about dates in the context of the observation / > >monitoring schema. > > > >Here are some of the types of dates that I've seen in just the data from > the > >NatureServe member programs based on either lack of available information > or > >interesting data collection situations. > > > >1) partial dates (only have the year or year-month) - definitely > >accommodated by the ISO 8601 format > > > >2) vague dates - for these I suppose you'd use ISO 8601 in > >EarliestCollectingDate / LatestCollectingDate, VerbatimDateTime, and the > >CollectingDatesInterpreted flag ? > > > >PRE-1975 > >post-1992 > >summer 2001 > >Mid-1990s > >late 1950's > >Circa 1941 > >Early 1990s > > > >3) a range of dates indicating that collection occurred on a specific > date > >sometime between those two limits and you're not sure when (example: > >Observations / collections from pitfall traps may have date ranges > >associated with them rather than a single date. For instance, you can > have > >dates of collection of 19Dec 2004 to 23Jan 2005 and the specimen was from > >some unknown specific date in that rage), > > > >4) continuous data collection over a period of time (some sort of sensor) > > > >5) information collected on one of two possible dates (one or the other > is > >correct, it's not a range) (example: aerial surveys flown on either May > 27 > >or June 04, 1999). > > > >It seems that EarliestCollectingDate / LatestCollectingDate could be used > >for #3, #4, and #5 - but is there a way to differentiate between these as > >actually being very different types of dates? Would those distinctions > just > >be communicated using the VerbatimDateTime? > > > >Of course for all of these examples the fallback would be to use the > >VerbatimDateTime, but it would be ideal to have as much as possible of > the > >date information in field(s) that can be queried and analyzed > > > >Thank you for your thoughts and help. > > > >Lynn > > > > > > > >Lynn Kutner > >NatureServe > >www.natureserve.org > >(303) 541-0360 > >lynn_kutner(a)natureserve.org > > > > > > > >From: Blum, Stan [mailto:sblum@calacademy.org] > >Sent: Thu 2/23/2006 6:41 PM > >To: Lynn Kutner; TDWG(a)LISTSERV.NHM.KU.EDU > >Subject: RE: Standards for date / time values? > > > > > >Hi Lynn, > > > >Context is everything, so I'm going to assume you are talking about > >date/time representations in the observation and monitoring schema(s) > that > >you are developing. The thinking in the collections community has gone > >something along the lines of this: > > > >Concept: the date-time of a collecting event [= recording-event, > >gathering-event] -- i.e., when one or more organisms were collected or > >observed -- expressed in the common Gregorian calendar, in local time. > > > >Requirements: > > > >1 - express the data/time exactly as it was recorded > >2 - retreive records by date/time ranges (date-time greater than X and/or > >less than Y) > >3 - accommodate date-times of varying precision, including explicit > >date-time ranges (specifying a duration) > >4 - support seasonal (time of year) queries > > > >These requirements can be met by the following fields: > > > >VerbatimDateTime > >EarliestDateCollected > >LatestDateCollected > >CollectingDatesInterpreted > >DayOfYear > > > >As John Wieczorek noted, the ISO 8601 format accommodates varying degrees > of > >precision. Using a "verbatim date-time" [text string] is as good as you > can > >do to satisfy the first requirement, short of scanning field notes or > voice > >recordings. The earliest and latest dates support the recording of > explicit > >ranges as well as interpreted ranges, which could be used to make "Summer > of > >1952" retrievable. The CollectingDatesInterpreted field would be a > boolean > >field, set as true when the earliest and latest dates represent > >interpretations rather than an explicit range. The "DayOfYear" field is > a > >compromise that we've offered as a simple way to support queries > involving > >seasonal (annual) cycles; e.g., collected in the northern summer, > regardless > >of year. But it can be argued that day of year is derivable from the > other > >fields (unless year is unknown), and that it doesn't accommodate explicit > >ranges. > > > >A bit more documentation is needed to address the odd cases (What do I do > >when ...?), but these five fields will support a lot of the data exchange > >needed for this concept. These fields are not intended to handle the > dating > >of localities in paleontology, nor are they intended to handle named > periods > >that are used in cultural collections (e.g., Iron Age, Victorian). > > > >ABCD uses a few more fields to handle the concept, > >http://ww3.bgbm.org/abcddocs/AbcdConcepts but some of these (date, time, > >and time zone) are handled by the ISO format, except when the larger > units > >are unkown; .e.g., the year is unknown, but the day is [ June 16 ]; or > the > >date is unknown, but the time is [ 14:00-15:30 ]. > > > >AbcdConcept0860 /DataSets/DataSet/Units/Unit/Gathering/DateTime > >AbcdConcept0861 /DataSets/DataSet/Units/Unit/Gathering/DateTime/DateText > >AbcdConcept0862 /DataSets/DataSet/Units/Unit/Gathering/DateTime/TimeZone > >AbcdConcept0863 > >/DataSets/DataSet/Units/Unit/Gathering/DateTime/ISODateTimeBegin > >AbcdConcept0864 > >/DataSets/DataSet/Units/Unit/Gathering/DateTime/DayNumberBegin > >AbcdConcept0865 > >/DataSets/DataSet/Units/Unit/Gathering/DateTime/TimeOfDayBegin > >AbcdConcept0866 > >/DataSets/DataSet/Units/Unit/Gathering/DateTime/ISODateTimeEnd > >AbcdConcept0867 > >/DataSets/DataSet/Units/Unit/Gathering/DateTime/DayNumberEnd > >AbcdConcept0868 > >/DataSets/DataSet/Units/Unit/Gathering/DateTime/TimeOfDayEnd > >AbcdConcept0869 > >/DataSets/DataSet/Units/Unit/Gathering/DateTime/PeriodExplicit > >The ABCD fields pretty much cover the entire concept space. One could > argue > >whether time-zone is relevant to the description of biological phenomena, > >but we do know that ship trawls do cross time-zones (including the > >date-line), and that daylight savings time could stretch or compress some > >nocturnal collecting events if their durations were calculated too > simply. > > > >To some extent these arguments are still going on, so analyze your > >requirements and your data, then state your position. ;-) > > > >Cheers, > > > >-Stan > >Stanley D. Blum, Ph.D. > >Research Information Manager > >California Academy of Sciences > >875 Howard St. > >San Francisco, CA > >+1 (415) 321-8183 > > > > > >-----Original Message----- > >From: Taxonomic Databases Working Group List > >[mailto:TDWG@LISTSERV.NHM.KU.EDU] On Behalf Of Lynn Kutner > >Sent: Thursday, February 23, 2006 9:12 AM > >To: TDWG(a)LISTSERV.NHM.KU.EDU > >Subject: Standards for date / time values? > > > > > >Hi - > >I'm working with a suite of date attributes that can include a > combination > >of precise dates, imprecise dates, and ranges of dates (and the same > types > >of time values). We'd like to follow existing standards. If this sort of > >date / time standard exists, I'd appreciate leads to the appropriate > >resources. > >Thank you for your help - > >Lynn > > > > > >Lynn Kutner > >Data Management Coordinator > >NatureServe > >Email: lynn_kutner(a)natureserve.org > >Phone: (303) 541-0360 > >www.natureserve.org > > Dra. Patricia Koleff > Directora de An�lisis y Prioridades > CONABIO > Comisi�n Nacional para el Conocimiento y Uso de la Biodiversidad > Av. Liga Periferico - Insurgentes Sur 4903 > Col. Parques del Pedregal > Delegacion Tlalpan > 14010 Mexico, D.F. > MEXICO > Tel. +52 (55) 5528 9105 > Fax +52 (55) 5528 9194 > www.conabio.gob.mx > e-mail: pkoleff(a)xolo.conabio.gob.mx >

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Re: Standards for date / time values?
by Richard Pyle 24 Feb '06

24 Feb '06

RE: CollectingDatesInterpreted When would this field *not* be set to true? In other words, what is the threshold for "interpreted", in terms of populating EarliestCollectingDate and LatestCollectingDate? At one extreme, we have a VerbatimDateTime of "12 January 2005, 13:34:15 local time". Not a lot of interpretation needed there (other than conversion of original documentation format to ASCII/Unicode, and interpretation of the time zone from the locality data). But conversion of "12 January 2005" to EarliestCollectingDate: "2005-01-12 00:00:00" LatestCollectingDate: "2005-01-12 23:59:59" ...requires a bit of interpretation. Maybe the time portion could simply be omitted; but even still, there is technically *some* interpretation when converting "January" to "01". And the spectrum continues on from there up until, well, stuff that would be unambiguously flagged as "interpreted". My point is, there should be some sort of guideline as to when to set CollectingDatesInterpreted true; i.e., what threshold of interpretation triggers that field. If such a guideline already exists, then I apologize for missing it. Personally, I don't think CollectingDatesInterpreted is necessary, really, because I have always regarded my equivalents of EarliestCollectingDate and LatestCollectingDate as interpreted. RE: Lynn's examples below. I wrestled with these issues (and more) a number of years ago. Other examples include "Summer; year unknown" (important for seasonal species), and multiple (non-contiguous) date ranges: "May or August, 2004" -- among others. In addition to the equivalents of VerbatimDateTime, EarliestCollectingDate, LatestCollectingDate; I had a controlled-vocabulary field called "DateRangeQualifier", which had an enumerated list of options tied to interpretation logic (e.g., "continuous range", "discontinuous range", "unknown point", "either/or", etc.; as well as sub-range qualifiers like "Summer"). I modelled it after an analogous field I use for interpreting paired or multiple georef coordinates (e.g., "transect" vs. "bounding box"; "polygon" vs. "linear"). This DateRangeQualifier approach ended up being too cumbersome to implement -- only because I was too lazy, and the number of cases that benefited from it (i.e., allowed computer logic to be applied, independent of a human reading of the VerbatimDateTime value) was low. The three fields VerbatimDateTime/EarliestCollectingDate/LatestCollectingDate will give you 90% of the value 90% of the time (at least for the specimen/observation data that I deal with). I wonder if DWC really needs more precision capability than that.... Rich Richard L. Pyle, PhD Database Coordinator for Natural Sciences Department of Natural Sciences, Bishop Museum 1525 Bernice St., Honolulu, HI 96817 Ph: (808)848-4115, Fax: (808)847-8252 email: deepreef(a)bishopmuseum.org http://hbs.bishopmuseum.org/staff/pylerichard.html -----Original Message----- From: Taxonomic Databases Working Group List [mailto:TDWG@LISTSERV.NHM.KU.EDU]On Behalf Of Lynn Kutner Sent: Thursday, February 23, 2006 5:26 PM To: TDWG(a)LISTSERV.NHM.KU.EDU Subject: Re: Standards for date / time values? Hi Stan and all - Yes, I am thinking about dates in the context of the observation / monitoring schema. Here are some of the types of dates that I've seen in just the data from the NatureServe member programs based on either lack of available information or interesting data collection situations. 1) partial dates (only have the year or year-month) - definitely accommodated by the ISO 8601 format 2) vague dates - for these I suppose you'd use ISO 8601 in EarliestCollectingDate / LatestCollectingDate, VerbatimDateTime, and the CollectingDatesInterpreted flag ? PRE-1975 post-1992 summer 2001 Mid-1990s late 1950's Circa 1941 Early 1990s 3) a range of dates indicating that collection occurred on a specific date sometime between those two limits and you're not sure when (example: Observations / collections from pitfall traps may have date ranges associated with them rather than a single date. For instance, you can have dates of collection of 19Dec 2004 to 23Jan 2005 and the specimen was from some unknown specific date in that rage), 4) continuous data collection over a period of time (some sort of sensor) 5) information collected on one of two possible dates (one or the other is correct, it's not a range) (example: aerial surveys flown on either May 27 or June 04, 1999). It seems that EarliestCollectingDate / LatestCollectingDate could be used for #3, #4, and #5 - but is there a way to differentiate between these as actually being very different types of dates? Would those distinctions just be communicated using the VerbatimDateTime? Of course for all of these examples the fallback would be to use the VerbatimDateTime, but it would be ideal to have as much as possible of the date information in field(s) that can be queried and analyzed Thank you for your thoughts and help. Lynn Lynn Kutner NatureServe www.natureserve.org (303) 541-0360 lynn_kutner(a)natureserve.org From: Blum, Stan [mailto:sblum@calacademy.org] Sent: Thu 2/23/2006 6:41 PM To: Lynn Kutner; TDWG(a)LISTSERV.NHM.KU.EDU Subject: RE: Standards for date / time values? Hi Lynn, Context is everything, so I'm going to assume you are talking about date/time representations in the observation and monitoring schema(s) that you are developing. The thinking in the collections community has gone something along the lines of this: Concept: the date-time of a collecting event [= recording-event, gathering-event] -- i.e., when one or more organisms were collected or observed -- expressed in the common Gregorian calendar, in local time. Requirements: 1 - express the data/time exactly as it was recorded 2 - retreive records by date/time ranges (date-time greater than X and/or less than Y) 3 - accommodate date-times of varying precision, including explicit date-time ranges (specifying a duration) 4 - support seasonal (time of year) queries These requirements can be met by the following fields: VerbatimDateTime EarliestDateCollected LatestDateCollected CollectingDatesInterpreted DayOfYear As John Wieczorek noted, the ISO 8601 format accommodates varying degrees of precision. Using a "verbatim date-time" [text string] is as good as you can do to satisfy the first requirement, short of scanning field notes or voice recordings. The earliest and latest dates support the recording of explicit ranges as well as interpreted ranges, which could be used to make "Summer of 1952" retrievable. The CollectingDatesInterpreted field would be a boolean field, set as true when the earliest and latest dates represent interpretations rather than an explicit range. The "DayOfYear" field is a compromise that we've offered as a simple way to support queries involving seasonal (annual) cycles; e.g., collected in the northern summer, regardless of year. But it can be argued that day of year is derivable from the other fields (unless year is unknown), and that it doesn't accommodate explicit ranges. A bit more documentation is needed to address the odd cases (What do I do when ...?), but these five fields will support a lot of the data exchange needed for this concept. These fields are not intended to handle the dating of localities in paleontology, nor are they intended to handle named periods that are used in cultural collections (e.g., Iron Age, Victorian). ABCD uses a few more fields to handle the concept, http://ww3.bgbm.org/abcddocs/AbcdConcepts but some of these (date, time, and time zone) are handled by the ISO format, except when the larger units are unkown; .e.g., the year is unknown, but the day is [ June 16 ]; or the date is unknown, but the time is [ 14:00-15:30 ]. AbcdConcept0860 /DataSets/DataSet/Units/Unit/Gathering/DateTime AbcdConcept0861 /DataSets/DataSet/Units/Unit/Gathering/DateTime/DateText AbcdConcept0862 /DataSets/DataSet/Units/Unit/Gathering/DateTime/TimeZone AbcdConcept0863 /DataSets/DataSet/Units/Unit/Gathering/DateTime/ISODateTimeBegin AbcdConcept0864 /DataSets/DataSet/Units/Unit/Gathering/DateTime/DayNumberBegin AbcdConcept0865 /DataSets/DataSet/Units/Unit/Gathering/DateTime/TimeOfDayBegin AbcdConcept0866 /DataSets/DataSet/Units/Unit/Gathering/DateTime/ISODateTimeEnd AbcdConcept0867 /DataSets/DataSet/Units/Unit/Gathering/DateTime/DayNumberEnd AbcdConcept0868 /DataSets/DataSet/Units/Unit/Gathering/DateTime/TimeOfDayEnd AbcdConcept0869 /DataSets/DataSet/Units/Unit/Gathering/DateTime/PeriodExplicit The ABCD fields pretty much cover the entire concept space. One could argue whether time-zone is relevant to the description of biological phenomena, but we do know that ship trawls do cross time-zones (including the date-line), and that daylight savings time could stretch or compress some nocturnal collecting events if their durations were calculated too simply. To some extent these arguments are still going on, so analyze your requirements and your data, then state your position. ;-) Cheers, -Stan Stanley D. Blum, Ph.D. Research Information Manager California Academy of Sciences 875 Howard St. San Francisco, CA +1 (415) 321-8183 -----Original Message----- From: Taxonomic Databases Working Group List [mailto:TDWG@LISTSERV.NHM.KU.EDU] On Behalf Of Lynn Kutner Sent: Thursday, February 23, 2006 9:12 AM To: TDWG(a)LISTSERV.NHM.KU.EDU Subject: Standards for date / time values? Hi - I'm working with a suite of date attributes that can include a combination of precise dates, imprecise dates, and ranges of dates (and the same types of time values). We'd like to follow existing standards. If this sort of date / time standard exists, I'd appreciate leads to the appropriate resources. Thank you for your help - Lynn Lynn Kutner Data Management Coordinator NatureServe Email: lynn_kutner(a)natureserve.org Phone: (303) 541-0360 www.natureserve.org

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Re: Standards for date / time values?
by Lynn Kutner 23 Feb '06

23 Feb '06

Hi Stan and all - Yes, I am thinking about dates in the context of the observation / monitoring schema. Here are some of the types of dates that I've seen in just the data from the NatureServe member programs based on either lack of available information or interesting data collection situations. 1) partial dates (only have the year or year-month) - definitely accommodated by the ISO 8601 format 2) vague dates - for these I suppose you'd use ISO 8601 in EarliestCollectingDate / LatestCollectingDate, VerbatimDateTime, and the CollectingDatesInterpreted flag ? PRE-1975 post-1992 summer 2001 Mid-1990s late 1950's Circa 1941 Early 1990s 3) a range of dates indicating that collection occurred on a specific date sometime between those two limits and you're not sure when (example: Observations / collections from pitfall traps may have date ranges associated with them rather than a single date. For instance, you can have dates of collection of 19Dec 2004 to 23Jan 2005 and the specimen was from some unknown specific date in that rage), 4) continuous data collection over a period of time (some sort of sensor) 5) information collected on one of two possible dates (one or the other is correct, it's not a range) (example: aerial surveys flown on either May 27 or June 04, 1999). It seems that EarliestCollectingDate / LatestCollectingDate could be used for #3, #4, and #5 - but is there a way to differentiate between these as actually being very different types of dates? Would those distinctions just be communicated using the VerbatimDateTime? Of course for all of these examples the fallback would be to use the VerbatimDateTime, but it would be ideal to have as much as possible of the date information in field(s) that can be queried and analyzed Thank you for your thoughts and help. Lynn Lynn Kutner NatureServe www.natureserve.org (303) 541-0360 lynn_kutner(a)natureserve.org ________________________________ From: Blum, Stan [mailto:sblum@calacademy.org] Sent: Thu 2/23/2006 6:41 PM To: Lynn Kutner; TDWG(a)LISTSERV.NHM.KU.EDU Subject: RE: Standards for date / time values? Hi Lynn, Context is everything, so I'm going to assume you are talking about date/time representations in the observation and monitoring schema(s) that you are developing. The thinking in the collections community has gone something along the lines of this: Concept: the date-time of a collecting event [= recording-event, gathering-event] -- i.e., when one or more organisms were collected or observed -- expressed in the common Gregorian calendar, in local time. Requirements: 1 - express the data/time exactly as it was recorded 2 - retreive records by date/time ranges (date-time greater than X and/or less than Y) 3 - accommodate date-times of varying precision, including explicit date-time ranges (specifying a duration) 4 - support seasonal (time of year) queries These requirements can be met by the following fields: VerbatimDateTime EarliestDateCollected LatestDateCollected CollectingDatesInterpreted DayOfYear As John Wieczorek noted, the ISO 8601 format accommodates varying degrees of precision. Using a "verbatim date-time" [text string] is as good as you can do to satisfy the first requirement, short of scanning field notes or voice recordings. The earliest and latest dates support the recording of explicit ranges as well as interpreted ranges, which could be used to make "Summer of 1952" retrievable. The CollectingDatesInterpreted field would be a boolean field, set as true when the earliest and latest dates represent interpretations rather than an explicit range. The "DayOfYear" field is a compromise that we've offered as a simple way to support queries involving seasonal (annual) cycles; e.g., collected in the northern summer, regardless of year. But it can be argued that day of year is derivable from the other fields (unless year is unknown), and that it doesn't accommodate explicit ranges. A bit more documentation is needed to address the odd cases (What do I do when ...?), but these five fields will support a lot of the data exchange needed for this concept. These fields are not intended to handle the dating of localities in paleontology, nor are they intended to handle named periods that are used in cultural collections (e.g., Iron Age, Victorian). ABCD uses a few more fields to handle the concept, http://ww3.bgbm.org/abcddocs/AbcdConcepts <http://ww3.bgbm.org/abcddocs/AbcdConcepts> but some of these (date, time, and time zone) are handled by the ISO format, except when the larger units are unkown; .e.g., the year is unknown, but the day is [ June 16 ]; or the date is unknown, but the time is [ 14:00-15:30 ]. * AbcdConcept0860 <http://ww3.bgbm.org/abcddocs/AbcdConcept0860> /DataSets/DataSet/Units/Unit/Gathering/DateTime * AbcdConcept0861 <http://ww3.bgbm.org/abcddocs/AbcdConcept0861> /DataSets/DataSet/Units/Unit/Gathering/DateTime/DateText * AbcdConcept0862 <http://ww3.bgbm.org/abcddocs/AbcdConcept0862> /DataSets/DataSet/Units/Unit/Gathering/DateTime/TimeZone * AbcdConcept0863 <http://ww3.bgbm.org/abcddocs/AbcdConcept0863> /DataSets/DataSet/Units/Unit/Gathering/DateTime/ISODateTimeBegin * AbcdConcept0864 <http://ww3.bgbm.org/abcddocs/AbcdConcept0864> /DataSets/DataSet/Units/Unit/Gathering/DateTime/DayNumberBegin * AbcdConcept0865 <http://ww3.bgbm.org/abcddocs/AbcdConcept0865> /DataSets/DataSet/Units/Unit/Gathering/DateTime/TimeOfDayBegin * AbcdConcept0866 <http://ww3.bgbm.org/abcddocs/AbcdConcept0866> /DataSets/DataSet/Units/Unit/Gathering/DateTime/ISODateTimeEnd * AbcdConcept0867 <http://ww3.bgbm.org/abcddocs/AbcdConcept0867> /DataSets/DataSet/Units/Unit/Gathering/DateTime/DayNumberEnd * AbcdConcept0868 <http://ww3.bgbm.org/abcddocs/AbcdConcept0868> /DataSets/DataSet/Units/Unit/Gathering/DateTime/TimeOfDayEnd * AbcdConcept0869 <http://ww3.bgbm.org/abcddocs/AbcdConcept0869> /DataSets/DataSet/Units/Unit/Gathering/DateTime/PeriodExplicit The ABCD fields pretty much cover the entire concept space. One could argue whether time-zone is relevant to the description of biological phenomena, but we do know that ship trawls do cross time-zones (including the date-line), and that daylight savings time could stretch or compress some nocturnal collecting events if their durations were calculated too simply. To some extent these arguments are still going on, so analyze your requirements and your data, then state your position. ;-) Cheers, -Stan Stanley D. Blum, Ph.D. Research Information Manager California Academy of Sciences 875 Howard St. San Francisco, CA +1 (415) 321-8183 -----Original Message----- From: Taxonomic Databases Working Group List [mailto:TDWG@LISTSERV.NHM.KU.EDU] On Behalf Of Lynn Kutner Sent: Thursday, February 23, 2006 9:12 AM To: TDWG(a)LISTSERV.NHM.KU.EDU Subject: Standards for date / time values? Hi - I'm working with a suite of date attributes that can include a combination of precise dates, imprecise dates, and ranges of dates (and the same types of time values). We'd like to follow existing standards. If this sort of date / time standard exists, I'd appreciate leads to the appropriate resources. Thank you for your help - Lynn Lynn Kutner Data Management Coordinator NatureServe Email: lynn_kutner(a)natureserve.org Phone: (303) 541-0360 www.natureserve.org <file://www.natureserve.org>

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Re: Standards for date / time values?
by Gail Kampmeier 23 Feb '06

23 Feb '06

Hi Lynn & John, Personally, I don't think that combined date fields are adequate, particularly for retrospective data capture. We have far too many insect labels with partial dates (tiny labels, tiny print, no room), which really mess up (probably also platform dependent screwups) when you try to enter the data as a date without one of the pieces. We've found all permutations--year only, month and year, month and day, well, maybe not day and year...but that's enough of a variety that we have all the fields individually broken out to accomodate this and then account for missing data in a calculated "pseudo" date by making assumptions depending on which piece may be missing. It also gives you greater flexibility and assuredness that you have the day and the month able to be put in the order desired or show the date in different formats such as 6.ix.1956, where the day and the month could easily be confused. Cheers! Gail >Hi Lynn, > >XML Schema, in its dateTime type, supports a subset of the ISO 8601 >datetime standard. The proposal for DwC2 currently recommends the >concepts EarliestDateCollected and LatestDateCollected, both as >dateTime types, to capture bounded or unbounded date/time >combinations of arbitrary specificity. These should be sufficient >except where lists of dates or other multiple date ranges are >required for a single record - unless I'm missing something, in >which case I'd like to know. > >Cheers, > >John > > >On 2/23/06, Lynn Kutner ><<mailto:Lynn_Kutner@natureserve.org>Lynn_Kutner(a)natureserve.org> >wrote: > >Hi - > >I'm working with a suite of date attributes that can include a >combination of precise dates, imprecise dates, and ranges of dates >(and the same types of time values). We'd like to follow existing >standards. If this sort of date / time standard exists, I'd >appreciate leads to the appropriate resources. > >Thank you for your help - >Lynn > > >Lynn Kutner >Data Management Coordinator >NatureServe >Email: <mailto:lynn_kutner@natureserve.org>lynn_kutner(a)natureserve.org >Phone: (303) 541-0360 >www.natureserve.org -- ====================== Gail E. Kampmeier Sr. Research Entomologist Illinois Natural History Survey Box 5 NSRC, 1101 W. Peabody Dr. Urbana, IL 61801 http://www.inhs.uiuc.edu/~gkamp ======================

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Re: Standards for date / time values?
by Blum, Stan 23 Feb '06

23 Feb '06

Hi Lynn, Context is everything, so I'm going to assume you are talking about date/time representations in the observation and monitoring schema(s) that you are developing. The thinking in the collections community has gone something along the lines of this: Concept: the date-time of a collecting event [= recording-event, gathering-event] -- i.e., when one or more organisms were collected or observed -- expressed in the common Gregorian calendar, in local time. Requirements: 1 - express the data/time exactly as it was recorded 2 - retreive records by date/time ranges (date-time greater than X and/or less than Y) 3 - accommodate date-times of varying precision, including explicit date-time ranges (specifying a duration) 4 - support seasonal (time of year) queries These requirements can be met by the following fields: VerbatimDateTime EarliestDateCollected LatestDateCollected CollectingDatesInterpreted DayOfYear As John Wieczorek noted, the ISO 8601 format accommodates varying degrees of precision. Using a "verbatim date-time" [text string] is as good as you can do to satisfy the first requirement, short of scanning field notes or voice recordings. The earliest and latest dates support the recording of explicit ranges as well as interpreted ranges, which could be used to make "Summer of 1952" retrievable. The CollectingDatesInterpreted field would be a boolean field, set as true when the earliest and latest dates represent interpretations rather than an explicit range. The "DayOfYear" field is a compromise that we've offered as a simple way to support queries involving seasonal (annual) cycles; e.g., collected in the northern summer, regardless of year. But it can be argued that day of year is derivable from the other fields (unless year is unknown), and that it doesn't accommodate explicit ranges. A bit more documentation is needed to address the odd cases (What do I do when ...?), but these five fields will support a lot of the data exchange needed for this concept. These fields are not intended to handle the dating of localities in paleontology, nor are they intended to handle named periods that are used in cultural collections (e.g., Iron Age, Victorian). ABCD uses a few more fields to handle the concept, http://ww3.bgbm.org/abcddocs/AbcdConcepts <http://ww3.bgbm.org/abcddocs/AbcdConcepts> but some of these (date, time, and time zone) are handled by the ISO format, except when the larger units are unkown; .e.g., the year is unknown, but the day is [ June 16 ]; or the date is unknown, but the time is [ 14:00-15:30 ]. * AbcdConcept0860 <http://ww3.bgbm.org/abcddocs/AbcdConcept0860> /DataSets/DataSet/Units/Unit/Gathering/DateTime * AbcdConcept0861 <http://ww3.bgbm.org/abcddocs/AbcdConcept0861> /DataSets/DataSet/Units/Unit/Gathering/DateTime/DateText * AbcdConcept0862 <http://ww3.bgbm.org/abcddocs/AbcdConcept0862> /DataSets/DataSet/Units/Unit/Gathering/DateTime/TimeZone * AbcdConcept0863 <http://ww3.bgbm.org/abcddocs/AbcdConcept0863> /DataSets/DataSet/Units/Unit/Gathering/DateTime/ISODateTimeBegin * AbcdConcept0864 <http://ww3.bgbm.org/abcddocs/AbcdConcept0864> /DataSets/DataSet/Units/Unit/Gathering/DateTime/DayNumberBegin * AbcdConcept0865 <http://ww3.bgbm.org/abcddocs/AbcdConcept0865> /DataSets/DataSet/Units/Unit/Gathering/DateTime/TimeOfDayBegin * AbcdConcept0866 <http://ww3.bgbm.org/abcddocs/AbcdConcept0866> /DataSets/DataSet/Units/Unit/Gathering/DateTime/ISODateTimeEnd * AbcdConcept0867 <http://ww3.bgbm.org/abcddocs/AbcdConcept0867> /DataSets/DataSet/Units/Unit/Gathering/DateTime/DayNumberEnd * AbcdConcept0868 <http://ww3.bgbm.org/abcddocs/AbcdConcept0868> /DataSets/DataSet/Units/Unit/Gathering/DateTime/TimeOfDayEnd * AbcdConcept0869 <http://ww3.bgbm.org/abcddocs/AbcdConcept0869> /DataSets/DataSet/Units/Unit/Gathering/DateTime/PeriodExplicit The ABCD fields pretty much cover the entire concept space. One could argue whether time-zone is relevant to the description of biological phenomena, but we do know that ship trawls do cross time-zones (including the date-line), and that daylight savings time could stretch or compress some nocturnal collecting events if their durations were calculated too simply. To some extent these arguments are still going on, so analyze your requirements and your data, then state your position. ;-) Cheers, -Stan Stanley D. Blum, Ph.D. Research Information Manager California Academy of Sciences 875 Howard St. San Francisco, CA +1 (415) 321-8183 -----Original Message----- From: Taxonomic Databases Working Group List [mailto:TDWG@LISTSERV.NHM.KU.EDU] On Behalf Of Lynn Kutner Sent: Thursday, February 23, 2006 9:12 AM To: TDWG(a)LISTSERV.NHM.KU.EDU Subject: Standards for date / time values? Hi - I'm working with a suite of date attributes that can include a combination of precise dates, imprecise dates, and ranges of dates (and the same types of time values). We'd like to follow existing standards. If this sort of date / time standard exists, I'd appreciate leads to the appropriate resources. Thank you for your help - Lynn Lynn Kutner Data Management Coordinator NatureServe Email: lynn_kutner(a)natureserve.org Phone: (303) 541-0360 www.natureserve.org <file://www.natureserve.org>

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