Dynamic visualisation of spatial and spatio-temporal probability density functions

Abstract

In this paper we will present and demonstrate aguila, a tool for interactive dynamic visualanalysis of gridded data that come as spatial or spatio-temporal probability distributionfunctions. Probability distribution functions are analysed in their cumulative form, and we canchoose to visualize exceedance probabilities given a threshold value, or its inverse, thequantile values. Threshold value or quantile level can be modified dynamically. In addition,classified probabilities in terms of (1-alpha)x100% (e.g. 95%) confidence or predictionintervals can be visualized for a given threshold value. Different modelling scenarios can becompared by organizing maps in a regular lattice, where individual maps (scenarios) areshown in panels that share a common legend and behave identically to actions like zooming,panning, and identifying (querying) cells. Variability over time is incorporated by showing setsof maps as animated movies. We will demonstrate this tool using sea floor sediment qualitypredictions under different spatial aggregation scenarios (block sizes), covering the Dutchpart of the North Sea. The tool is freely available in binary and source code form; source codeis distributed under the Gnu GPL; grid maps are read from disc through the GDAL library, orfrom memory as e.g. in an R session.