Methods for visualising complex water quality data

Includes abstract.Includes bibliographical references (leaves 157-173).The quality of South Africa’s over-stretched water resources is a matter of concern for all who depend on them for their survival and prosperity, so access to the relevant monitoring data is essential. Visualisation is a powerful method for analysing these data and communicating the results, because it unloads complex cognitive processes from the fairly restricted human numerical processing structures onto the highly developed visual perception system. Developments in the field of visualisation during the past two decades have yielded many practical methods that are applicable to the analysis and presentation of water quality data. Judicious use of visualisation aids aquatic scientists, water resource managers and ordinary consumers in assessing the quality of their water and deciding on remedial measures. To provide some insight into the possibilities of visualisation techniques, I analyse and discuss five visual methods that I have developed or contributed to: multivariate time-series inventory plots; multivariate map symbols; spatially-referenced inventory of water quality data; mass transfer summary plots; and the use of visual methods in communicating the ecological status of rivers to a wide audience