how to assert an uncertainty on a measured value

[smrgeoinfo]

GKM has quantified physical property with value and uom, but there doesn't seem to be a way to assert uncertainty. Can use Particular.determinedBy for the measurement method, but this doesn't allow assertion of metadata about the measured value. In the earlier version of the model, things like 'standard deviation', 'mean', 'mode', 'uncertainty' were expressed as abstract properties on a Physical Property instance. We might need to re instate these.

[smrgeoinfo]

resolved, have uncertainty quality now