The Benthic (Topographic) Position Index (Weiss 2001) grid indicates the topographic positions of the cells. Positive TPI values represent locations that are higher than the average of their surrounding (ridges); negative TPI values represent locations that are lower than their surrounding (valleys); TPI values near zero are either flat areas or areas of constant slope. The benthic position index grid was derived from the bathymetry grid of Darwin Harbour. Please see the metadata of the bathymety grid for more details (GeoCat No: 74915).
Weiss, A.D., 2001. Topographic position and landforms analysis. In: ESRI international user
conference, 9-13 July 2001, San Diego, CA.