DTV12 — Missing and incorrect text in clause 10.6

Specification: DTV v1.1

Title: Missing and incorrect text in clause 10.6

Summary:

In clause 10.6 (Time Coordinates), the introduction suggests that a time coordinate can represent more than one time point. This is false. A time coordinate represents exactly one time point (which is nowhere stated). It can only combine time point identifiers to refer to a different time point.

The verb concept 'time coordinate has time scale' appears in the UML diagram and in one of the definitions, but nowhere in the text.

In the entry for 'time coordinate', the two dichotomies are stated as possibilities in the Notes. They should be stated as Necessities.

The definitions of absolute and relative time coordinates refer to their "corresponding to" time intervals. The time points correspond, but the coordinates only "refer to" them.

Upon examination, the RTF determined that an atomic time coordinate indicates exactly one time point. A compound time coordinate, and therefore time coordinates in general, indicates at most one time point, and may not indicate any (documented) time point. For example, March 3 does not indicate any documented time point. This necessitates a number of minor changes to the model, and to the wording of many definitions in 10.6.
With this understanding, only an atomic time coordinate has a time scale, and that concept is added.
The dichotomies are restated as Necessities, and shown in the UML diagrams. The definitions of absolute and relative time coordinates are modified as recommended, and other inconsistencies are also repaired.
There is a significant overlap of the changes associated with this issue and the changes associated with Issues 18989, 18991, 19529, and 19635.
Issue 18989 and 18991 (duplicates) were resolved to determine that a time coordinate is a conceptual structure of meaning rather than a representation of a time point. This affects the UML diagrams in 10.6, the wording of the introductory text, and the wording of many of the definitions being altered by Issue 19547. In particular this results in elaborating the model of atomic time coordinate.
Issue 18991 also makes parallel changes to the wording of Clause 9.1 and 9.2.
Issue 19529 points out that the definitions of ‘compound time coordinate’ and ‘compound time coordinate combines atomic time coordinate’ are circular. The resolution of that issue is to define a compound time coordinate to be a set of atomic time coordinates, but to ‘combine’ time coordinates in general. The revised definitions must also take into account the fact that compound time coordinates do not necessarily indicate time points. Those changes are therefore merged into the Revised Text below.
Issue 19635 requires an editorial change to move a misplaced paragraph in 10.6.3. In addition, the revised entry for ‘compound time coordinate includes atomic time coordinate’ is moved to follow the entry for ‘compound time coordinate’.