Observation events

Glossary: Observation Event vs. Observation

In line with international data-sharing standards (Darwin Core / GBIF), the OpenBioMaps data structure divides field data collection into two distinct levels: the Observation Event and the Observation. This division ensures that both structured surveys and casual observations can be accurately recorded.

1. Observation Event

An Observation Event is a predefined spatial and temporal context representing a specific data collection or sampling activity.

- Key point: The event itself is the field activity (the act of sampling), not the organism found.

Main characteristics:

It always has a recorded location (coordinates or a fixed point) and a time (or time interval).

It is often associated with a specific methodology or protocol (e.g. 5-minute point count, trapping).

Handling ‘zero observations’ (absence): An Observation Event is created and remains valid in the system even if the researcher did not observe a single species during the survey.

• This ‘negative data’ is crucial for scientific analysis and for documenting sampling effort.

Hierarchy: An Observation Event may contain zero, one or more individual observations (Observation). The observations recorded during the event share a common identifier: the observation_list_id.

2. Observation

An Observation is the individual detection or recording of a specific taxon (species, genus, etc.) in the field.

• Essence: This is the biological data itself, evidence of the organism’s presence.

Main characteristics:

It contains the taxon name (species name), as well as the counted or estimated number of individuals (or other quantitative indicator). It always includes a location and a date and time.

Types in the system:

- Event-linked observation: Species data recorded as part of a structured survey (Observation Event). In this case, the location and time data are inherited from the event or specified within it. - Opportunistic Observation: An individual sighting that is not part of a pre-planned protocol or survey, but is recorded immediately on an ad hoc basis (e.g. a rare bird spotted whilst out and about).

Summary table for developers and users

Characteristic	Observation	Event Observation
What does it represent?	The context of fieldwork/sampling.	The sighting of a specific organism.
Can it be left blank?	Yes. If, according to the protocol, nothing was found, the event still exists.	No. It must always include species and number of individuals.
Quantitative indicator	The sampling effort (duration, area size).	Number of individuals, coverage, count.
GBIF / DwC equivalent	Event / Sampling-event data	Occurrence / Occurrence data