17.1.2 How it Works

To describe an activity requires two parts; you must specify:

• An activity template, which is a general descriptions of possible activity types. A template is a semantic description of what the activity is about and the types of parameters that could be involved in the activity.

For example, we can specify a template to describe the creation of any data object (see the example in Section 17.1.3.4 Example ). The mandatory output for the template is one or more new data objects. The possible inputs are unlimited so that the template can accommodate the needs (potential complexity) of any data object in an earth model.

A template may be very generic (for example, if the exporting software does not capture detailed descriptions of activities). Or the templates may be very detailed and precise in providing semantic information about the parameters involved in the activity.

• An instance of an activity. The instance describes an activity that has actually occurred. Each instance is associated with a template, which provides its semantics.

As part of a RESQML transfer, a “writer” (software creating data for transfer) must include the most current templates along with the activity instances for the data objects contained in the data transfer. A “reader” uses the templates to understand the activity instances.

To specify relationships between data objects—for example, to attach an activity to the data object(s) it impacts or to attach a template to an activity—use a data object reference. For more information on how data object references work, see 5.4 Specifying Relationships in RESQML .