A note on the use of equidistant contours for presenting scientific data

Abstract: The passionate plea for the use of scientific colour maps misses some aspects in the visual presentation of scientific data. While a linear colour map based on scientific human colour perception is useful for the presentation of some images, like the three examples given of the topography of the earth, an apple and a passport photograph, scientific data are not presented. In this note it will be shown that there is more in scientific oceanographic data as they are presented in forms varying from historic equidistant contours, via a linear black-(grey)-white b&w map, a linear colour map and a nonlinear colour map. From an objective perspective, equidistant contouring is the best means for presenting scientific information in a relatively unbiased way. Nonlinear colour maps may add information to that by highlighting certain aspects also by varying the colour range if needed. Such information is not available from linear colour maps. Finally, the aesthetic aspect of visual data presentation is discussed.