8.4 How to format extendedMeasurementOrFact tables

8.4.0.1 What data goes into eMoF

Any data related to abiotic or biotic measurements, including sampling information and protocols, can be included in the eMoF table. While you can also use the MeasurementOrFact extension, OBIS strongly recommends using extendedMeasurementOrFact instead, particularly if your data is formatted with an Event core. The key difference is that eMoF allows you to link measurements to either an event or an occurrence by including occurrenceID in the schema. This opens up many more opportunities to link your data with any kind of measurement!

Required terms for eMoF include:

eventID (this links the record to the Event Core table)
occurrenceID (this links the record to the Occurrence Core or Occurrence Extension table, it may be left blank in cases where a measurement links to an event instead of an occurrence)

Other potential fields are shown in the table below (also listed in the checklist):

Class Event | DwC:habitat
Class Event | DwC:sampleSizeUnit
Class Event | DwC:sampleSizeValue
Class Event | DwC:samplingEffort
Class Event | DwC:samplingProtocol
Class Occurrence | DwC:behavior
Class Occurrence | DwC:individualCount
Class Occurrence | DwC:lifeStage
Class Occurrence | DwC:organismQuantity
Class Occurrence | DwC:organismQuantityType
Class Occurrence | DwC:sex
Class Occurrence | DwC:type
Class Measurement | DwC:measurementAccuracy
Class Measurement | DwC:measurementDeterminedBy
Class Measurement | DwC:measurementDeterminedDate
Class Measurement | DwC:measurementID
Class Measurement | DwC:measurementMethod
Class Measurement | DwC:measurementRemarks
Class Measurement | DwC:measurementType*
Class Measurement | DwC:measurementTypeID*
Class Measurement | DwC:measurementUnit*
Class Measurement | DwC:measurementUnitID*
Class Measurement | DwC:measurementValue
Class Measurement | DwC:measurementValueID

*For measurementTypeID, measurementUnitID, and measurementValueID you must use controlled vocabulary terms. We know choosing the correct vocabulary term can be challenging, so we have provided some guidance on how to select the correct vocabulary and are continuously working to improve guidelines. It is strongly recommended to ensure these fields are filled as correctly as possible. Missing or incorrect terms will be documented in the measurementOrFact reports.

8.4.0.2 How to structure eMoF

Structuring data for the eMoF extension may be one of the more confusing extensions in the data formatting process. It may help to think of this extension as the table that contains all information related to any kind of measurement.

Rather than documenting each of your measurements in separate columns (e.g., columns for biomass, abundance, length, gear size, percent cover, etc.), these measurements will be condensed into one column: measurementValue. measurementType describes what the measurement actually is, for example whether it is an abundance value, length, percent cover, or any other biotic/abiotic measurement. measurementUnit is used to indicate the unit of the measurement.

By linking measurementType and measurementValue with the identifiers eventID and/or occurrenceID, you can have measurements linked to one event (e.g. temperature), measurements link to occurrence records (e.g. length), as well as sampling facts that are linked to events (size, gear, etc.). Information specifically related to how samples were taken will have the measurementTypes: sampleSizeValue, sampleSizeUnit, samplingEffort, and samplingProtocol.

8.4.0.3 Stepwise Guidance to Format eMoF Table (in Excel)

Create a blank sheet and name it eMoF
Add 9 column headers for:
- eventID, occurrenceID, measurementType, measurementValue, measurementUnit, measurementTypeID, measurementValueID, measurementUnitID, measurementRemarks
Copy eventID values from your Occurrence table and paste into the eventID field in your new, blank eMoF table
- Repeat for occurrenceID from the Occurrence table
Copy the first column of measurement values, paste into the measurementValue field
- Fill measurementType with the name of the variable (e.g., count, length, etc.)
Add unit of measurements where applicable to the measurementUnit field
For any other measurements related to occurrences, repeat steps 3-5, pasting additional measurements below the preceding ones
- Be sure to copy and paste the associated occurrenceIDs and/or eventIDs for the additional measurements
Fill the fields measurementTypeID, measurementUnitID, and measurementValueID with controlled vocabularies that suit your data (see vocabulary guidelines)
Repeat steps 3-7 for any measurements in the Event table

Note the fields sampleSizeValue, samplingEffort, and samplingProtocol from the Occurrence table can be documented as separate measurements on different rows in the eMoF table. E.g., measurementType = samplingProtocol, measurementValue = description of protocol. Any values in sampleSizeUnit fields should be placed in the measurementUnit field when transferred to the eMoF.

Watch the video tutorial for how to format the eMoF table below.

If you would like to export Event data to the eMoF, see some example R code below. This example was provided by Abby Benson from the OBIS-USA node.

library(dplyr)
cruise <- unique(eventCore[c("eventID")]) #create a list of all unique eventIDs from your event table
cruise <- cruise %>% #add sampling information 
mutate(measurementType = "Sampling platform name",
measurementValue = "R/V Cruise Id = SR1812",
measurementValueID = "https://doi.org/10.7284/908021",
measurementUnit = "",
measurementTypeID = "http://vocab.nerc.ac.uk/collection/Q01/current/Q0100001/",
measurementUnitID = "",
occurrenceID = "")