I hesitated to respond to this earlier because I am not up on what is going on in the "observation" community of tdwg and how they define things. However, I have a philosophical problem with saying that HumanObservations and MachineObservations should be typed as dcterm:type=dcmitype:Event. My problem stems from the way that we use "observation" in English.
1. When a taxonomist conducts a field collecting trip (a dcterm:event) at a certain time and place, we end up with a specimen (dcterm:type=dcmitype:PhysicalObject, dwc:basisOfRecord="PhysicalSpecimen"). 2. When a photographer conducts a photo shoot (a dcterm:event) at a certain time and place, we end up with a still image (dcterm:type=dcmitype:StillImage, dwc:basisOfRecord="StillImage"). 3. When a birdwatcher conducts an observation (a dcterm:event) at a certain time and place, we end up with an observation (dcterm:type=???, dwc:basisOfRecord="HumanObservation").
In example 3, the problem is that we use the same word ("Observation") for the act of observing and the product that we create when we observe. We don't do this for other types of things that belong in the dwc:recordClass = dwctype:Occurrence (i.e. examples 1 and 2). If you look at the elements in the DwC class Occurrence, you see elements that can describe the things that are created when we document the presence of an individual, e.g. catalogNumber, preparations, sex, etc. If you look at the elements in the Dwc class Event, you see elements related to the act of creating, e.g. the time (eventDate), place (habitat), and method (samplingProtocol). The use of the word Event to describe a DwC class is true to the DCMI definition of Event: "Metadata for an event provides descriptive information that is the basis for discovery of the purpose, location, duration, and responsible agents associated with an event. Examples include an exhibition, webcast, conference, workshop, open day, performance, battle, trial, wedding, tea party, conflagration." The examples given in the definition all indicate things that happen, not the things that result from those happenings (i.e. exhibitions, not exhibits; conference, not proceedings; battle, not dead people; tea party, not tea; etc.).
As I look at the DCMI classes, the problem is that I don't think there is one that describes observation (in the sense of an Occurrence, i.e. the product that is created when we observe). So I think that the appropriate thing in the case of observation is either to provide no value for dcterm:type or to petition DCMI to create a class for observations (if we can get them to understand the distinction that I'm making between act and product). I do not think that the appropriate thing is to call observations (sensu created product) something that they are not. I have previously raised the question of "Why do we need dcterms:type?". I do not think that the reason is to satisfy our need to place all things into conceptual boxes. I think the reason is to let a machine or user know what kinds of metadata to expect when they are told that a record has a particular value for dcterms:type. Under that rationale, if a record identifier is for an observation is being resolved and a consuming application is told that the record has a dcterm:type of Event, that application is going to be expecting metadata about an act (time, place, and method), not metadata about a created entity (catalog number, sex, or whatever types of things that you record about an observation). It is better to tell the machine nothing than to tell it to expect the wrong thing. While it is true that observations have a time, place, and method of creation, PhysicalObjects and StillImages also have a time, place, and method of their creation, yet we do not class them as Events. Let's not put a round peg into a square hole. Either leave the peg out or drill a round hole.
Steve Baskauf
John R. WIECZOREK wrote:
Found a moment to get back to this. There currently is no formal (that is, rdf) relation between observations and dcmitype:Event. In fact, there are no formal relations between recommended basisOfRecord values ("PreservedSpecimen", "StillImage", "HumanObservation") and any dcmitype terms (dcmitype:PhysicalObject, dcmitype:StillImage, dcmitype:Event). The former are string literals in a list that is recommended while the latter are the DC recommended Type Vocabulary for dcterms:type.
So, if I was to publish a record for a human observation of a species in nature (a dwc:Occurrence), I would populate the terms as follow (note specifically the use of terms for type and recordClass and the use of a string for basisOfRecord):
dcterms:type = dcmitype:Event dwc:basisOfRecord = "HumanObservation" dwc:recordClass = dwctype:Occurrence
For your other example I would populate the terms similarly, with:
dcterms:type = dcmitype:Event dwc:basisOfRecord = "MachineObservation" dwc:recordClass = dwctype:Occurrence