Geography Reference
In-Depth Information
3 Background: Principles of Display Design
Display design (Wickens et al.
2004
) comprise 13 principles, including those that
aid the perception of the user and attention-based principles. Geographically
speaking, the most important is the Proximity Compatibility Principle (PCP)
(Wickens
1992
; Wickens et al.
2004
). The PCP is intended to exploit the strengths
of human attention abilities. It states that information that is used together in a
mental operation, should be displayed in a way that is compatible with that mental
operation. For example, if the operator requires the integration of two pieces of data
(e.g. volume and temperature) into a single value (e.g. pressure in a container), then
there would be greater benefits in human performance if the single integrated value
were displayed. Alternatively, if the mental task is to compare two pieces of data for
anomalies, then it makes sense to display these two pieces of data, perhaps side-by-
side or even overlay, to facilitate visual comparison. In this way, we achieve
compatibility between the mental task (task proximity) and the display represen-
tation (display proximity). The latter one—display proximity—can manifest itself
in several ways, all of which are intuitive from a geographic point of view.
The first of these display proximities explored is spatial proximity. This way of
promoting PCP has in general, proven useful for interface design of control panels
(e.g. Chapanis and Yoblick
2001
). A second strategy uses connections (lines) to
link related information (enclosure by lines have also been used in previous case
studies). In the past, this strategy has not proved to be more effective than prox-
imity in stimulating human attention (see Chapanis and Yoblick
2001
; Huotari
et al.
2004
). Other ways include source similarity (making information that is
needed to be mentally integrated similar), code homogeneity (using symbology to
classify the information), object manipulation (e.g. aggregation of discrete data to
produce higher order continuous information, as in the interpolation of spot
heights to produce contours) and proximity through configuration (relies on human
ability to recognise patterns, such as with Chernoff faces, e.g. Dorling
1994
)
(Wickens and Carswell
1995
).
Most of these principles can be linked to counterparts in cartographic design.
The most pertinent principles will be outlined and discussed in the following two
case studies.
4 Case Study 1: Southern Region Communication Centre
(SRCC) Study
4.1 Geography and Set-up of the SRCC
The SRCC is based in Dunedin and at the time of the study was one of seven
ambulance centres operating in New Zealand. It receives over 30,000 calls per
year from a population of approximately 273,500; 60 % of which are in Dunedin
