Temporal Coverage

Definition

Describes the time period during which the data was collected.

  • <Time_Type> provides the time system used to describe the data.
  • <Date_Type> specifies the type of date represented.
  • <Temporal_Range_Type> specifies how temporal coverage is specified for the collection.
  • <Precision_Of_Seconds> refers to the precision (position in number of places to right of decimal point) of seconds used in measurement.
  • <Ends_At_Present_Flag> specifies that a data collection which covers, temporally, a discontinuous range, currently ends at the present date.
  • <Range_DateTime> the start and end date/time of a collection.
    • <BeginningDateTime> The time when the temporal coverage period begins.
    • <EndingDateTime> The time when the temporal coverage period ends.
  • <Single_DateTime> a single date associated with the data collection
  • <Periodic_DateTime> specifies the name of the temporal period in addition to the date, time, duration unit, and value, and cycle duration unit and value. This information is used at the collection level to describe a collection having granules, which cover a regularly occurring period.
    • <Name> the name given to the recurring time period.
    • <Start_Date> provides the date (day and time) of the first occurrence of this regularly occurring period.
    • <End_Date>provides the date (day and time) of the last occurrence of this regularly occurring period.
    • <Duration_Unit> is the unit specification for the period duration.
    • <Duration_Value> is the number of PeriodDurationUnits in the period.
    • <Period_Cycle_Duration_Unit> is the unit specification of the period cycle duration.
    • <Period_Cycle_Duration_Value> is the value of the attribute.
  • <Paleo_DateTime> is the length of time represented by the data collected.
    • <Paleo_Temporal_Coverage> should be used when the data spans time frames earlier than yyyy-mm-dd = 0001-01-01.
    • <Paleo_Start_Date> is the number of years furthest back in time including units Ga, Ma, ka or ybp.
    • <Paleo_Stop_Date> is the number of years closest to the present time including units Ga, Ma, ka or ybp.
    • <Chronostratigraphic_Unit> is a controlled keyword describing Geologic Time of the form:
      • <Eon> is the primary and largest division of geologic time. Limits correspond with major, global crustal events, changes in sea level and/or climate, or biotic changes.
      • <Era> is a major division of geological time, tens or hundreds of millions of years long, usually distinguished by significant changes in the plant and animal kingdoms; also used to denote later archaeological periods, such as the prehistoric era. Five geologic eras have been established: Archeozoic [before 2500 million years ago (Ma)], Proterozoic (2500 to 570 Ma), Paleozoic (570 Ma to ca. 250 Ma), Mesozoic (ca. 250 to ca. 70 Ma), and Cenozoic (since ca. 70 Ma). All eras are divided into at least two geologic periods.
      • <Period> is the secondary division of geologic time, delimited by moderate but usually global crustal events, changes in sea level and/or climate, or biotic changes, sometimes in a relatively localized area. Two or more periods are required to make up a geologic era, and each period comprises two or more geologic epochs.
      • <Epoch> is the third-order division of geologic time, delimited by partial withdrawal of the sea from land masses and by gentle crustal disturbances in localized areas. Two or more epochs are required to make up a geologic period, and, in turn, two or more periods are needed to constitute a geologic era.
      • <Stage> is a smaller unit of time. An Epoch usually has 1 or more Stages.
  • <Ancillary_Temporal_Keyword> specifies a word or phrase which serves to summarize the temporal characteristics referenced in the collection.
 
Syntax
<Temporal_Coverage>    
   <Time_Type>Text</Time_Type>    
   <Date_Type>Text</Date_Type>    
   <Temporal_Range_Type>Text</Temporal_Range_Type>    
   <Precision_Of_Seconds>An integer value</Precision_Of_Seconds>    
   <Ends_At_Present_Flag>A boolean value</Ends_At_Present_Flag>  
..Choice of..    
   (1) <Range_DateTime>          
          <Beginning_Date_Time>A date, dateTime, or Enumeration</Beginning_Date_Time>          
          <Ending_Date_Time>A date, dateTime, or Enumeration</Ending_Date_Time>        
       </Range_DateTime>    
   (2) <Single_DateTime>A date, dateTime, or Enumeration</Single_DateTime>    
   (3) <Periodic_DateTime>          
          <Name>Text</Name>          
          <Start_Date>A date, dateTime, or Enumeration</Start_Date>          
          <End_Date>A date, dateTime, or Enumeration</End_Date>          
          <Duration_Unit>A duration unit enumeration</Duration_Unit>          
          <Duration_Value>An integer value</Duration_Value>          
          <Period_Cycle_Duration_Unit>A duration unit enumeration</Period_Cycle_Duration_Unit>          
          <Period_Cycle_Duration_Value>An integer value</Period_Cycle_Duration_Value>        
        </Periodic_DateTime>    
    (4) <Paleo_DateTime>          
        <Paleo_Start_Date>years [GA, Ma, ka, or ybp]</Paleo_Start_Date>          
        <Paleo_Stop_Date>years [Ga, Ma, ka, or ybp]</Paleo_Stop_Date>          
        <Chronostratigraphic_Unit>Chronostratigraphic Unit keywords</Chronostratigraphic_Unit>        
        </Paleo_DateTime>    
    <Temporal_Info>      
       <Ancillary_Temporal_Keyword>Text</Ancillary_Temporal_Keyword>    
    </Temporal_Info>  
</Temporal_Coverage>
 
Usage
  • <Temporal_Coverage> is required and may be repeated
  • One of <Range_DateTime>, <Single_DateTime>, <Periodic_DateTime> or <Paleo_DateTime> is required
    • All 4 choice subfields can be repeated.
    • Subfields within the choice options cannot be repeated
  • <Time_Type> is optional and repeatable.
  • <Date_Type> is optional and repeatable.
  • <Temporal_Range_Type> is optional.
  • <Precision_Of_Seconds> is optional.
  • <Ends_At_Present_Flag> is optional and must be a boolean (True or False) value.
  • DateTime fields must be in date (YYY-MM-DD) or dateTime (YYYY-MM-DDTHH:MM:SS) format. Other accepted values are: unknown, present, unbounded, future or not provided.
  • <Duration_Unit> must be DAY, MONTH, or YEAR
  • <Periodic_DateTime> is optional, repeatable, and if the subfields are populated, they are required.
  • The <Paleo_DateTime> is optional and may be repeated.
    • <Paleo Start Date> and <Paleo Stop Date> are highly recommended subfields and may not be repeated, but when they occur, they must occur together, i.e. both <Paleo Start Date> and <Paleo Stop Date> must be included.
    • <Paleo Start Date> and <Paleo Stop Date> must include units of time, e.g. Ga, Ma, ka and ybp; where Ga = billion years ago, Ma = million years ago, Ka = thousand years ago and ybp = years before present (present being about 1950).
    • The <Chronostratigraphic Unit> subfield is recommended and may be repeated.
    • <Chronostratigraphic Unit> must be selected from the <Chronostratigraphic Unit> keywords.
  • <Ancillary_Temporal_Keyword> is optional and repeatable
Example
  <Temporal_Coverage>
     <Time_Type>Universal Time</Time_Type>
     <Date_Type>Eastern Daylight</Date_Type>
     <Temporal_Range_Type>Long Range</Temporal_Range_Type> 
     <Precision_Of_Seconds>1</Precision_Of_Seconds> 
     <Ends_At_Present_Flag>True</Ends_At_Present_Flag> 
     <Range_DateTime>
         <Beginning_Date_Time>1990-01-01T00:00:00Z</Beginning_Date_Time>  
          <Ending_Date_Time>2003-12-31T00:00:00Z</Ending_Date_Time>  
     </Range_DateTime>
  </Temporal_Coverage>

<Temporal_Coverage>    
     <Range_DateTime>      
      <Beginning_Date_Time>2004-08-22</Beginning_Date_Time>      
      <Ending_Date_Time>2001-12-31</Ending_Date_Time>    
     </Range_DateTime>    
     <Periodic_DateTime>     
         <Period_Cycle_Duration_Unit>DAY</Period_Cycle_Duration_Unit>    
      </Periodic_DateTime>    
      <Temporal_Info>      
     &nsbp; <Ancillary_Temporal_Keyword>Daily</Ancillary_Temporal_Keyword>    
      </Temporal_Info>
</Temporal_Coverage>



<Temporal_Coverage>    
      <Single_DateTime>2015-06-01T00:00:00Z</Single_DateTime>    
      <Periodic_DateTime>      
         <Period_Cycle_Duration_Unit>DAY</Period_Cycle_Duration_Unit>    
      </Periodic_DateTime>  
</Temporal_Coverage>



<Temporal_Coverage>    
     <Periodic_DateTime>      
         <Name>Northern Hemisphere</Name>      
         <Start_Date>2000-03-01T00:00:00Z</Start_Date>      
         <End_Date>2010-06-30T00:00:00Z</End_Date>      
         <Duration_Unit>MONTH</Duration_Unit>      
         <Duration_Value>4</Duration_Value>      
         <Period_Cycle_Duration_Unit>YEAR</Period_Cycle_Duration_Unit>      
         <Period_Cycle_Duration_Value>10</Period_Cycle_Duration_Value>    
     </Periodic_DateTime>  
</Temporal_Coverage>





        

 

This document should be cited as:
Directory Interchange Format (DIF) Writer's Guide, 2018.
Global Change Master Directory.
National Aeronautics and Space Administration.
[https://gcmd.gsfc.nasa.gov/add/difguide/].