TEACHING CARTOGRAPHIC UNCERTAINTY
D.D. Fraser
RMIT University, School of Mathematical and Geospatial
Sciences, Melbourne, Australia
david.fraser@rmit.edu.au
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.