ObservationCollection
As defined in OMS :
A collection of similar Observations #19
For each observation, we can add a property, for example 'CollectionReference'. Like that it would be easy to connect each observation of a same set of observations together.
What it is important, I think is not to confuse a collection of observation with a type of observation. For example, if we have 2 boreholes SPT_1 and SPT_2 with 2 NSPT value. In total, we have 4 observations (2 in each borehole). Here, all these 4 observations has the type 'SPT', 2 have 'SPT1' has 'CollectionReference' property and the 2 others have 'SPT2' has 'CollectionReference' property.
More details here.
An ObservationCollection can have 0..* Observations

Following the ObservationTypology discussed in April.
Several specializations of ObservationCollection are proposed:
- Serie Observation : A collection of Observations that observed the same property thanks to the same procedure repeated in either time or space,
- Parallel Observation : A collection of Observations obtained by following a unique procedure that adress several observed properties based on a single act of observation,
- Parallel series : A collection of Serie Observations that themselves address one ObservedProperty.
- Serie of ParallelObservations : A collection of ParallelObservations. ParallelObservations that are repeated in either time or space.