SDD Part 0: Introduction and Primer to the SDD Standard

4.5 Elements within <SamplingEvent>

The element <SamplingUnit> contains raw sample data for a specimen. <SamplingEvent> contains information about where and when that sampling occurred.

A simple SDD instance document representing a sampling event has the basic structure shown below and in example 4.5.1.1.

Example 4.5.1.1 - A simple sampling event

<SampleData>
   <SamplingEvent id="TJM45337">
   <DateTime minute="17" hour="7" day="17" month="7" year="2006"/>
   <DateTimeSpanEnd minute="27" hour="7" day="17" month="7" year="2006"/>
   <GeographicArea ref="g2"/>
   <Coordinates latitude="20.44" longitude="139.29"/>
      <SamplingUnit>
         <Quantitative ref="ch1" value="12"/>
      </SamplingUnit>
                     ...etc
</SampleData>

<DateTime> records the date and time when the sampling event occurred, either as a single time point or as the start of a time period.

<DateTimeSpanEnd> records the end of a time span if event timing is recorded as such. Both date/times may be incomplete in ways not expressible in xs:datetime, e.g. the day and year may be known, but month unknown.

<GeographicArea> is a reference to a geographic area at which the event occurred. This is defined in the element <GeographicAreas> with the basic structure shown below and in example 4.5.1.2.

Example 4.5.1.2 Defining geographic areas

<GeographicAreas>
  <GeographicArea id="g1">
    <Representation>
      <Label>Worldwide</Label>
    </Representation>
  </GeographicArea>
  <GeographicArea id="g2">
    <Representation>
      <Label>Europe</Label>
    </Representation>
  </GeographicArea>
</GeographicAreas>

<Coordinates> records a point on earth at which the event occurred. Elements available are <Latitude>, <Longitude>, <GeodeticDatum>; <Verbatim> (a textual representation of the original location data) and <Literal> (a free-form string in addition to or instead of numeric coordinates (i.e. Charley's Creek, near Chinchilla).

Example 4.5.1.3 Use of the <Coordinate> element

<SampleData>
 <SamplingEvent id="AQ578462">
  <DateTime></DateTime>
   <Coordinates latitude="26.5" longitude="150.5" 
           geodeticdatum="GDA94" verbatim="5km NW of Roma"/>
    <SamplingUnit>
     <Categorical ref="c1">
      <State ref="s1"/>
     </Categorical>
    </SamplingUnit>
 </SamplingEvent>
</SampleData>

4.5.2. SamplingUnit

A sampling unit may be an individual organism, a leaf of a tree, a piece of tissue, etc. In each sampling unit multiple characters may have been observed together ('paired observations'). Example: 'leaf shape, length, and width' of a single leaf). Value frequencies (e. g., '2.3': observed 4 x) are not supported; they are useful when only a single character variable is supported, but complicate paired observations unnecessarily. Char. values with a frequency should be entered in repeated SamplingUnits.

A simple SDD code snippet representing part of the sample data above has the basic structure shown below and in Example 4.5.2.1.

Example 4.5.2.1. Recording sampling data in SDD

  <SampleData>
    <SamplingEvent id="sev1000">
    <DateTime></DateTime>
      <SamplingUnit>
        <Categorical ref="c1">
          <State ref="s2"/>
        </Categorical>
        <Quantitative ref="c2" value="110"/>
      </SamplingUnit>
      <SamplingUnit>
        <Categorical ref="c1">
          <State ref="s1"/>
        </Categorical>
        <Quantitative ref="c2" value="112"/>
      </SamplingUnit>
      <SamplingUnit>
        <Categorical ref="c1">
          <State ref="s1"/>
        </Categorical>
        <Quantitative ref="c2" value="110"/>
      </SamplingUnit>
      <SamplingUnit>
        <Categorical ref="c1">
          <State ref="s1"/>
        </Categorical>
        <Quantitative ref="c2" value="118"/>
      </SamplingUnit>
    </SamplingEvent>
  </SampleData>

-- DonovanSharp - 21 Jun 2006