Scale in a digital geographic world

The representative fraction, the metric traditionally used by cartographers to characterize the level of geographic detail in a map, is not well defined for digital geographic data. Increasingly complex and unsatisfactory conventions are needed to preserve this legacy of earlier technology. A series of requirements is defined for replacement metrics. For digital representations of fields, six cases can be identified, but in only two cases is there a straightforward solution to the requirements. For digital representations of discrete objects, the representative fraction can be replaced with any ordinal index of specification. The authors conclude that simple metrics having dimensions of length are preferable to the complex conventions required to specify the representative fraction for digital geographic data.