D.D. Fraser

RMIT University, School of Mathematical and Geospatial Sciences, Melbourne, Australia



Cartometry relates to the metric nature of cartography and the issues associated with data error, certainty, accuracy and precision. The present day mapping environment requires that all base data and cartographic information is stored originally in digital form. The transformation of the content of a digital spatial database into spatial information products poses many challenges. An understanding of the database properties, restrictions, manipulations, processes and appropriate display options in this digital environment is necessary if the digital data is to be effectively converted into information for the end user. The basic geometry of spatial data and the restrictions associated with digital data must be taught to all students of cartography.

This paper presents the results from a set of exercises designed to demonstrate the impact of uncertainty on cartographic products. The selection of exercises presented here relate to the representation of geographical and administrative boundaries; the numerical recording of digital data; the use of vectors to define boundaries; data reduction; and GPS and map accuracy.

The exercises were undertaken by cartography and geomatics students in the third year of the Bachelor of Applied Science at the RMIT University in Melbourne, Australia. The aim was to heighten student awareness of the need to consider cartographic uncertainty. The results outlined in the paper show why all cartographers must consider the metric nature of cartography and the associated data quality issues.