Review and comments on Plot-X

2021-07-20 Simon J D Cox

Plot-X appears to be a fairly faithful implementation of parts of the model proposed in [TERN-Plot]https://ternaustralia.github.io/ontology_tern-plot/, including the Project, Site and SiteVisit classes, with Feature, Observation, Sampling from https://www.w3.org/TR/vocab-ssn/ .

These comments pick out a few places where minor changes might be beneficial.

Keys and IDs

The model follows E-R conventions, where both Primary- and Foreign-keys are given a name AaaBbbID.

Note that in an RDF implementation, the link from one resource (entity) to another will be through an 'object-property' which should have a name like hasCccDdd or isEeeGggOf whose value is the URI (identifier) of the target resource (entity). i.e. Don't put 'ID' in the name of RDF properties acting as pointers to other resources ('foreign keys').

AaaBbbID should be reserved for the assigned identifier, else it is confusing.

Site

swPoint - this is an unusual anchor point, it is more common to specify centroid. But OK.

Feature

(latitude, longitude, elevation) - Consider linking to a (3D?) Point instead - i.e. maintain a separate Point table
what is the distinction between elevation vs altitude? and depth? They are all vertical coordinates. (Is depth measured positive down?)

Observation

Some attribute names are inconsistent with O&M/SOSA

parameter instead of sosa:observedProperty
method instead of sosa:usedProcedure
instrumentType + observer instead of sosa:madeBySensor

Sampling

sampleFeatureID appears to appear in place of sosa:result

Is there a separate table/class for samples, or does this attribute just loop back to another row in the Feature table (I'm not fully familiar with E-R diagrams)

*Attribute

Why is the value called 'result'?
Is there a relationship between *Attribute::attribute and Observation::parameter?