Geographic Information Systems: An Introduction, 3rd Edition

11.7 Temporal Accuracy

According to ISO (2001), temporal accuracy should include the following elements:

1. Accuracy of a time measurement—correctness of the temporal references of an item (reporting of error in time measurement)
2. Temporal consistency—correctness of ordered events or sequences, if reported
3. Temporal validity—validity of data with respect to time

Temporal accuracy refers to the coincidence between registered and actual time or the time coordinate for the event or phenomena, stated, for example, as +/− 1 hour or +/− 1 day. In addition, temporal accuracy can be defined as the correctness of ordered events or sequences. The specification of temporal accuracy is dependent on the ability to measure time objectively in a common temporal coordinate system.

It is important to state how long the data are valid—temporal validity; without this, it is easy for data to be used incorrectly. Temporal validity is an important element in GIS and is particularly linked to timeliness. Timeliness is normally indicated by the date of registry, such as the dates on aerial photographs, photogrammetric data, and satellite data, and the dates of surveys, accidents, water leakage, and the like.

Two situations may affect the timeliness of data:

1. When the geometry and attributes of existing objects have been altered
2. When new objects, with geometry and attributes, have appeared

The degree of timeliness required depends on object type and data application. Public works agencies and utilities often ...