PRESENTATION OF DATA IN SPACE AND TIME

Data. which are as varied as those under consideration, cover a region as large as Australia and range over long periods of time, by necessity present readers with major problems and demand a compromise between lucidity and sophistication. This page presents quantitative values as well as qualitative indicators, but cannot eliminate the need for consultation of original data whenever vital decisions are at stake. It can only serve as a survey of knowledge available in 1972, provide an understanding of basic processes and yield first base-lines for preliminary planning and design. Moreover, it enables people familiar with their immediate surroundings to isolate features which are common or differ from those at nearby stations.

With these objectives in mind, a method of visualization of facts and time histories of processes has been developed which imposes only a few demands on users' previous experience with similar material and allows them to survey at one glance the entire Australian coast. The underlying principle rests on the fact that most of Australia's coast can be projected from a suitably selected centre in a unique manner on to a circle by means of radii drawn through coastal stations. A system of circles surrounding Australia thus provides a scheme for the graphical presentation of variations of parameters in time or of their absolute values at coastal stations. With the exception of a few sections of the Gulf of Carpentaria, the South Australian Gulfs, Bass Strait and Tasrnania, most localities of Australia's coast can be projected uniquely from the point 13410' E, 2910' S on to such a system of circles.

Certain parameters range over several orders of magnitude. For example, the populations of townships vary from a few hundreds to several millions. For this reason, in a second scheme, the concentric circles are spaced logarithmically.

The equidistant pattern is convenient for the presentation of qualitative and descriptive material, such as distributions of minerals, fish species and landforms, when every ring is allotted to a different class of object. Anyone object is presented by a ray drawn to that particular ring. Or, when the radii become time axes as in the case of tide recording history, equidistant circles demarcate hours, half or full days, months, or years.

Many of the processes under consideration have a wave character. For example, monthly average water and air temperatures and monthly mean sea levels go through a complete cycle in the course of one year, while tidal heights have periods of twelve or twenty-four hours . Whenever a ray from the centre of the circles through a coastal location is used as reference line for the time history of a process, the start of the time graph is located on the innermost circle. Positive values of the parameter under consideration are plotted in the anti-clockwise direction. Thus, the tidal height at Darwin (DN) in the North is drawn to the left of the ray corresponding to this station, while at Thevenard (TV) in the South it is drawn to the right-hand side.

Selected stations with more reliable data are denoted by the two-letter codes:

AL Albany

BA Bamaga

BB Brisbane

BM Broome

BG Bundaberg

BT Burnie

BU Bunbury

CA Cairns

+CC Sydney

CH Coffs Harbour

CI Port McArthur

CN Carnarvon

CT Cooktown

DN Darwin

ED Eden

ES Esperance

EU Eucla

FM Fremantle

GN Geraldton

HT Hobart

LD Point Lonsdale

LN Launceston

MB Melville Bay

MK Mackay

CN Newcastle

OH Adelaide

PD Dampier

PF Port Fairy

PH Port Hedland

PK Port Kembla

PL Port Lincoln

PM Port MacDonnell

ST Stanley

TV Thevenard

TL Townsville

VH Victor Harbor

WP Weipa PM

WY Wyndham