Standards for date / time values?

Lynn Kutner Lynn_Kutner at NATURESERVE.ORG
Thu Feb 23 22:26:07 CET 2006


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 at natureserve.org

________________________________

From: Blum, Stan [mailto:sblum at calacademy.org]
Sent: Thu 2/23/2006 6:41 PM
To: Lynn Kutner; TDWG at 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 at LISTSERV.NHM.KU.EDU] On Behalf Of Lynn Kutner
        Sent: Thursday, February 23, 2006 9:12 AM
        To: TDWG at 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 at natureserve.org 
        Phone:   (303) 541-0360 
        www.natureserve.org <file://www.natureserve.org>  


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<DIV id=idOWAReplyText95884 dir=ltr>
<DIV dir=ltr><FONT face=Arial color=#0000ff size=2>Hi Stan and all - 
</FONT></DIV>
<DIV dir=ltr><FONT color=#0000ff size=2></FONT>&nbsp;</DIV>
<DIV dir=ltr><FONT color=#0000ff size=2>Yes, I am thinking about dates in the 
context of the observation / monitoring schema.</FONT></DIV>
<DIV dir=ltr><FONT color=#0000ff size=2></FONT>&nbsp;</DIV>
<DIV dir=ltr><FONT color=#0000ff size=2>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.</FONT></DIV>
<DIV dir=ltr><FONT color=#0000ff size=2></FONT>&nbsp;</DIV>
<DIV dir=ltr><FONT color=#0000ff size=2>1) partial dates (only have the year or 
year-month)&nbsp;- definitely accommodated by the ISO 8601 format </FONT></DIV>
<DIV dir=ltr><FONT color=#0000ff><FONT size=2></FONT><FONT 
size=2></FONT></FONT>&nbsp;</DIV>
<DIV dir=ltr><FONT size=2><FONT color=#0000ff>2) vague&nbsp;dates - for these I 
suppose you'd use ISO 8601 in EarliestCollectingDate / LatestCollectingDate, 
<SPAN class=607414522-23022006><FONT face=Arial color=#0000ff 
size=2>VerbatimDateTime, and the <SPAN class=607414522-23022006><FONT face=Arial 
color=#0000ff size=2>CollectingDatesInterpreted 
flag</FONT></SPAN>&nbsp;?</FONT></SPAN></FONT></DIV>
<DIV dir=ltr align=left><SPAN><FONT face=Arial color=#0000ff 
size=2></FONT></SPAN>&nbsp;</DIV>
<DIV dir=ltr><FONT color=#0000ff><FONT face=Arial size=2>PRE-1975</FONT> 
</FONT></DIV>
<DIV dir=ltr align=left><SPAN><FONT face=Arial color=#0000ff 
size=2>post-1992</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN><FONT face=Arial color=#0000ff size=2>summer 
2001</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN><FONT face=Arial color=#0000ff 
size=2>Mid-1990s</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN><FONT face=Arial color=#0000ff size=2>late 
1950's</FONT></SPAN></DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2>Circa 
1941</FONT></DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2>Early 
1990s</FONT></DIV>
<DIV dir=ltr align=left><FONT color=#0000ff></FONT>&nbsp;</DIV>
<DIV dir=ltr align=left><FONT color=#0000ff>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:<FONT size=2>&nbsp; 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),</FONT></FONT></DIV>
<DIV dir=ltr align=left><FONT color=#0000ff></FONT>&nbsp;</DIV>
<DIV dir=ltr align=left>
<DIV dir=ltr align=left><FONT color=#0000ff><SPAN class=406235723-23022006><FONT 
face=Arial size=2>4)&nbsp;</FONT></SPAN><FONT face=Arial><FONT size=+0><FONT 
size=2><SPAN class=406235723-23022006>continuous data collection over a period 
of time (some sort of sensor)</SPAN></FONT></FONT></FONT></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Arial><FONT size=+0><FONT color=#0000ff 
size=2><SPAN class=406235723-23022006></SPAN></FONT></FONT></FONT>&nbsp;</DIV>
<DIV dir=ltr align=left><FONT color=#0000ff><FONT face=Arial><FONT size=+0><FONT 
size=2><SPAN class=406235723-23022006>5) </SPAN></FONT></FONT></FONT>information 
collected on one of two possible dates (one or the other is correct, it's not a 
range) <FONT face=Arial><FONT size=+0><FONT size=2><SPAN 
class=406235723-23022006>(example: aerial surveys flown on either May 27 or June 
04, 1999). </SPAN></FONT></FONT></FONT></FONT></DIV>
<DIV dir=ltr align=left><FONT color=#0000ff><FONT face=Arial><FONT size=+0><FONT 
size=2><SPAN 
class=406235723-23022006></SPAN></FONT></FONT></FONT></FONT>&nbsp;</DIV>
<DIV dir=ltr align=left><FONT color=#0000ff><FONT face=Arial><FONT size=+0><FONT 
size=2><SPAN class=406235723-23022006>It seems that EarliestCollectingDate / 
LatestCollectingDate could be used for #3, #4, and #5 - but is there a way to 
</SPAN></FONT></FONT></FONT></FONT><FONT color=#0000ff><FONT face=Arial><FONT 
size=+0><FONT size=2><SPAN class=406235723-23022006>differentiate between these 
as actually being very different types of dates? Would those distinctions just 
be communicated using the <SPAN class=607414522-23022006><FONT face=Arial 
color=#0000ff 
size=2>VerbatimDateTime?</FONT></SPAN></SPAN></FONT></FONT></FONT></FONT></DIV>
<DIV dir=ltr align=left><FONT color=#0000ff><FONT face=Arial><FONT size=+0><FONT 
size=2><SPAN 
class=406235723-23022006></SPAN></FONT></FONT></FONT></FONT>&nbsp;</DIV>
<DIV dir=ltr align=left><FONT color=#0000ff><FONT face=Arial><FONT size=+0><FONT 
size=2><SPAN class=406235723-23022006>
<DIV dir=ltr align=left><FONT color=#0000ff><FONT face=Arial><FONT size=+0><FONT 
size=2><SPAN class=406235723-23022006>Of course for all of these examples the 
fallback would be to use the <SPAN class=607414522-23022006><FONT face=Arial 
color=#0000ff size=2>VerbatimDateTime, but it would be ideal to have as much as 
possible of&nbsp;the date information in field(s) that can be queried and 
analyzed</FONT></SPAN></SPAN></FONT></FONT></FONT></FONT></DIV>
<DIV dir=ltr align=left><FONT color=#0000ff><FONT face=Arial><FONT size=+0><FONT 
size=2><SPAN class=406235723-23022006><SPAN 
class=607414522-23022006></SPAN></SPAN></FONT></FONT></FONT></FONT>&nbsp;</DIV></SPAN></FONT></FONT></FONT></FONT></DIV>
<DIV dir=ltr align=left><FONT color=#0000ff><FONT face=Arial><FONT size=+0><FONT 
size=2><SPAN class=406235723-23022006>Thank you for your thoughts and 
help.</SPAN></FONT></FONT></FONT></FONT></DIV>
<DIV dir=ltr align=left><FONT color=#0000ff><FONT face=Arial><FONT size=+0><FONT 
size=2><SPAN 
class=406235723-23022006></SPAN></FONT></FONT></FONT></FONT>&nbsp;</DIV>
<DIV dir=ltr align=left><FONT color=#0000ff><FONT face=Arial><FONT size=+0><FONT 
size=2><SPAN 
class=406235723-23022006>Lynn</SPAN></FONT></FONT></FONT></FONT></DIV></DIV></FONT>
<DIV dir=ltr><FONT size=2></FONT>&nbsp;</DIV>
<DIV dir=ltr><FONT size=2></FONT>&nbsp;</DIV>
<DIV dir=ltr><FONT face=Arial color=#000000 size=2></FONT>&nbsp;</DIV></DIV>
<DIV id=idSignature50309 dir=ltr>
<DIV><FONT face=Arial color=#000000 size=2>Lynn Kutner</FONT></DIV>
<DIV><FONT size=2><EM>NatureServe</EM></FONT></DIV>
<DIV><FONT size=2><A 
href="http://www.natureserve.org">www.natureserve.org</A></FONT></DIV>
<DIV><FONT size=2>(303) 541-0360</FONT></DIV>
<DIV><FONT size=2><A 
href="mailto:lynn_kutner at natureserve.org">lynn_kutner at natureserve.org</A></FONT></DIV></DIV>
<DIV dir=ltr><BR>
<HR tabIndex=-1>
<FONT face=Tahoma size=2><B>From:</B> Blum, Stan 
[mailto:sblum at calacademy.org]<BR><B>Sent:</B> Thu 2/23/2006 6:41 
PM<BR><B>To:</B> Lynn Kutner; TDWG at LISTSERV.NHM.KU.EDU<BR><B>Subject:</B> RE: 
Standards for date / time values?<BR></FONT><BR></DIV>
<DIV>
<DIV><SPAN class=607414522-23022006><FONT face=Arial color=#0000ff size=2>Hi 
Lynn,</FONT></SPAN></DIV>
<DIV><SPAN class=607414522-23022006><FONT face=Arial color=#0000ff 
size=2></FONT></SPAN>&nbsp;</DIV>
<DIV><SPAN class=607414522-23022006><FONT face=Arial color=#0000ff 
size=2>Context is everything, so I'm going to assume you are talking about 
date/time representations in the observation and monitoring&nbsp;schema(s) that 
you are developing.&nbsp; The thinking in the collections community has gone 
something along the lines of this:</FONT></SPAN></DIV>
<DIV><SPAN class=607414522-23022006><FONT face=Arial color=#0000ff 
size=2></FONT></SPAN>&nbsp;</DIV>
<DIV><SPAN class=607414522-23022006><FONT face=Arial color=#0000ff 
size=2>Concept:&nbsp; 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.</FONT></SPAN></DIV>
<DIV><SPAN class=607414522-23022006><FONT face=Arial color=#0000ff 
size=2></FONT></SPAN>&nbsp;</DIV>
<DIV><SPAN class=607414522-23022006><FONT face=Arial color=#0000ff 
size=2>Requirements:&nbsp; </FONT></SPAN></DIV>
<DIV><SPAN class=607414522-23022006><FONT face=Arial color=#0000ff 
size=2></FONT></SPAN>&nbsp;</DIV>
<DIV><SPAN class=607414522-23022006><FONT face=Arial color=#0000ff size=2>1 - 
express the&nbsp;data/time exactly as it was recorded</FONT></SPAN></DIV>
<DIV><SPAN class=607414522-23022006><FONT face=Arial color=#0000ff size=2>2 - 
retreive records by date/time ranges (date-time greater than X&nbsp;and/or less 
than Y) </FONT></SPAN></DIV>
<DIV><SPAN class=607414522-23022006><FONT face=Arial color=#0000ff size=2>3 - 
accommodate date-times of varying precision, including explicit date-time ranges 
(specifying a duration)</FONT></SPAN></DIV>
<DIV><SPAN class=607414522-23022006><FONT face=Arial color=#0000ff size=2>4 - 
support seasonal (time of year) queries</FONT></SPAN></DIV>
<DIV><SPAN class=607414522-23022006><FONT face=Arial color=#0000ff 
size=2></FONT></SPAN>&nbsp;</DIV>
<DIV><SPAN class=607414522-23022006><FONT face=Arial color=#0000ff size=2>These 
requirements can be met by the following fields:</FONT></SPAN></DIV>
<DIV><SPAN class=607414522-23022006><FONT face=Arial color=#0000ff 
size=2></FONT></SPAN>&nbsp;</DIV>
<DIV><SPAN class=607414522-23022006><FONT face=Arial color=#0000ff 
size=2>VerbatimDateTime</FONT></SPAN></DIV>
<DIV><SPAN class=607414522-23022006><FONT face=Arial color=#0000ff 
size=2>EarliestDateCollected</FONT></SPAN></DIV>
<DIV><SPAN class=607414522-23022006><FONT face=Arial color=#0000ff 
size=2>LatestDateCollected</FONT></SPAN></DIV>
<DIV><SPAN class=607414522-23022006><FONT face=Arial color=#0000ff 
size=2>CollectingDatesInterpreted</FONT></SPAN></DIV>
<DIV><SPAN class=607414522-23022006>
<DIV><SPAN class=607414522-23022006><FONT face=Arial color=#0000ff 
size=2>DayOfYear</FONT></SPAN></DIV></SPAN></DIV>
<DIV><SPAN class=607414522-23022006><FONT face=Arial color=#0000ff 
size=2></FONT></SPAN>&nbsp;</DIV>
<DIV><SPAN class=607414522-23022006><FONT face=Arial color=#0000ff size=2>As 
John Wieczorek noted, the ISO 8601 format accommodates varying degrees of 
precision.&nbsp; 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.&nbsp; 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.&nbsp; The CollectingDatesInterpreted field would 
be a boolean field, set as true when the earliest and latest dates represent 
interpretations rather than an explicit range.&nbsp; 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.&nbsp; But it can be argued that&nbsp;day of year&nbsp;is derivable from 
the other fields (unless year is unknown),&nbsp;and that it doesn't accommodate 
explicit ranges.&nbsp; </FONT></SPAN></DIV>
<DIV><SPAN class=607414522-23022006><FONT face=Arial color=#0000ff 
size=2></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=607414522-23022006>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.&nbsp; 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).&nbsp; </SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN 
class=607414522-23022006></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial color=#0000ff size=2>ABCD uses a&nbsp;<SPAN 
class=607414522-23022006>few </SPAN>more fields<SPAN class=607414522-23022006> 
to handle the concept</SPAN>, </FONT><A 
href="http://ww3.bgbm.org/abcddocs/AbcdConcepts"><FONT face=Arial 
size=2>http://ww3.bgbm.org/abcddocs/AbcdConcepts</FONT></A><FONT 
face=Arial><FONT color=#0000ff><FONT size=2>&nbsp;<SPAN 
class=607414522-23022006>&nbsp;</SPAN></FONT></FONT></FONT></SPAN><SPAN 
class=607414522-23022006><FONT face=Arial color=#0000ff size=2>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 ].</FONT></SPAN></DIV>
<DIV><SPAN class=607414522-23022006><FONT face=Arial color=#0000ff 
size=2></FONT></SPAN>&nbsp;</DIV>
<DIV><SPAN class=607414522-23022006>
<LI>
<P><A href="http://ww3.bgbm.org/abcddocs/AbcdConcept0860">AbcdConcept0860</A> 
<TT>&nbsp;/DataSets/DataSet/Units/Unit/Gathering/DateTime&nbsp;</TT> </P>
<LI>
<P><A href="http://ww3.bgbm.org/abcddocs/AbcdConcept0861">AbcdConcept0861</A> 
<TT>&nbsp;/DataSets/DataSet/Units/Unit/Gathering/DateTime/DateText&nbsp;</TT> 
</P>
<LI>
<P><A href="http://ww3.bgbm.org/abcddocs/AbcdConcept0862">AbcdConcept0862</A> 
<TT>&nbsp;/DataSets/DataSet/Units/Unit/Gathering/DateTime/TimeZone&nbsp;</TT> 
</P>
<LI>
<P><A href="http://ww3.bgbm.org/abcddocs/AbcdConcept0863">AbcdConcept0863</A> 
<TT>&nbsp;/DataSets/DataSet/Units/Unit/Gathering/DateTime/ISODateTimeBegin&nbsp;</TT> 
</P>
<LI>
<P><A href="http://ww3.bgbm.org/abcddocs/AbcdConcept0864">AbcdConcept0864</A> 
<TT>&nbsp;/DataSets/DataSet/Units/Unit/Gathering/DateTime/DayNumberBegin&nbsp;</TT> 
</P>
<LI>
<P><A href="http://ww3.bgbm.org/abcddocs/AbcdConcept0865">AbcdConcept0865</A> 
<TT>&nbsp;/DataSets/DataSet/Units/Unit/Gathering/DateTime/TimeOfDayBegin&nbsp;</TT> 
</P>
<LI>
<P><A href="http://ww3.bgbm.org/abcddocs/AbcdConcept0866">AbcdConcept0866</A> 
<TT>&nbsp;/DataSets/DataSet/Units/Unit/Gathering/DateTime/ISODateTimeEnd&nbsp;</TT> 
</P>
<LI>
<P><A href="http://ww3.bgbm.org/abcddocs/AbcdConcept0867">AbcdConcept0867</A> 
<TT>&nbsp;/DataSets/DataSet/Units/Unit/Gathering/DateTime/DayNumberEnd&nbsp;</TT> 
</P>
<LI>
<P><A href="http://ww3.bgbm.org/abcddocs/AbcdConcept0868">AbcdConcept0868</A> 
<TT>&nbsp;/DataSets/DataSet/Units/Unit/Gathering/DateTime/TimeOfDayEnd&nbsp;</TT> 
</P>
<LI>
<P><A href="http://ww3.bgbm.org/abcddocs/AbcdConcept0869">AbcdConcept0869</A> 
<TT>&nbsp;/DataSets/DataSet/Units/Unit/Gathering/DateTime/PeriodExplicit&nbsp;</TT></SPAN></P></LI></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN 
class=607414522-23022006></SPAN></FONT><FONT face=Arial color=#0000ff 
size=2><SPAN class=607414522-23022006>The ABCD fields pretty much cover the 
entire concept space.&nbsp; 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&nbsp;collecting events if their durations 
were calculated too simply.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN 
class=607414522-23022006></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=607414522-23022006>To 
some extent these arguments are still going on, so analyze your requirements and 
your data, then state your position.&nbsp; ;-)</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN 
class=607414522-23022006></SPAN></FONT><FONT face=Arial color=#0000ff 
size=2><SPAN class=607414522-23022006></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN 
class=607414522-23022006>Cheers,</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN 
class=607414522-23022006></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN 
class=607414522-23022006>-Stan</SPAN></FONT></DIV>
<P><FONT size=2>Stanley D. Blum, Ph.D.<BR>Research Information 
Manager<BR>California Academy of Sciences<BR>875 Howard St.<BR>San 
Francisco,&nbsp; CA<BR>+1 (415) 321-8183<BR><BR></FONT></P>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
  <DIV></DIV>
  <DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left><FONT 
  face=Tahoma size=2>-----Original Message-----<BR><B>From:</B> Taxonomic 
  Databases Working Group List [mailto:TDWG at LISTSERV.NHM.KU.EDU] <B>On Behalf Of 
  </B>Lynn Kutner<BR><B>Sent:</B> Thursday, February 23, 2006 9:12 
  AM<BR><B>To:</B> TDWG at LISTSERV.NHM.KU.EDU<BR><B>Subject:</B> Standards for 
  date / time values?<BR><BR></FONT></DIV>
  <P><FONT face=Arial size=2>Hi - </FONT></P>
  <P><FONT face=Arial size=2>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.</FONT></P>
  <P><FONT face=Arial size=2>Thank you for your help -</FONT> <BR><FONT 
  face=Arial size=2>Lynn</FONT> </P><BR>
  <P><FONT face="Comic Sans MS" size=2>Lynn Kutner</FONT> <BR><I><FONT 
  face="Comic Sans MS" color=#808080 size=2>Data Management 
  Coordinator</FONT></I> <BR><I><FONT face="Comic Sans MS" color=#808080 
  size=2>NatureServe</FONT></I> <BR><FONT face="Comic Sans MS" color=#808080 
  size=2>Email:&nbsp;&nbsp;&nbsp; lynn_kutner at natureserve.org</FONT> <BR><FONT 
  face="Comic Sans MS" color=#808080 size=2>Phone:&nbsp;&nbsp; (303) 
  541-0360</FONT> <BR><A href="file://www.natureserve.org"><U></U><U><FONT 
  face="Comic Sans MS" color=#0000ff 
  size=2>www.natureserve.org</FONT></U></A><FONT face="Comic Sans MS" size=2> 
  </FONT></P></BLOCKQUOTE></DIV></BODY></HTML>


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