Visualization of Dutch shoreface dynamics

Abstract

This research is focused on creating visualization methods for the dynamics in the Shoreface. For this it uses the JARKUS dataset. This JARKUS data contains the height measurements by high precision bathymetry of the dunes, beach and underwater shoreface. In order to show the development of the height elevation over time for the period 2000-2010 the research focuses on the location of areas with a lot of dynamics. This research only focuses on the north coast of Ameland. The Dutch practise of water management is an important factor for the analysis and visualization of the dynamics. This research targets to add value by elaborating on the location of the dynamics and not on the coastal profiles. The objective of this study is to develop and test a visualization to show the morphologic dynamics of the shoreface. Where there are options to focus on line or field object this report is focused on the evolution of the height dynamic of point locations. The problem to tackle is how to visualize the dynamics of the shoreface morphology. The fact that the research is focused on the underwater dynamics leads to a difficulty. The area is highly influenced by several natural and artificial processes. Where the land morphology is seen to be quite solid, the dune, beach, and shoreface are constantly developing. Also the multidimensional aspect of the JARKUS data is of influence on the research. The questions that are central in this research are: 1. What morphologic features in the shoreface are of interest? 2. What dynamics are present in the shoreface of north Ameland? 3. How to visualize the dynamics of the shoreface? 4. How are the dynamic visualizations understood? The research starts with a literature review of the coastal morphological phenomena and dynamics to answer the first research questions. The first question is about the morphological features that exist in the shoreface of the Dutch coast. This is followed by the identification of the dynamics of the shoreface and the processes that influence the situation on Ameland. It is identified that the morphological features in the shoreface that are of interest on de mid-term timescale are the longshore bars and rip channels. The development of these elements under the influence of the natural and artificial circumstances can be shown by displaying the dynamics in height over time. The second part of the research, question three and four, focus on a more practical approach. First there is elaborated on the influence of different graphic parameters on the perception of maps. Then in order to visualize the data, the JARKUS data has been preprocessed. This includes, interpolating the coastal profiles, normalization, and classification of the data, and the transforming of the raster to a vector dataset with point data. The resulting visualizations are coded with the use of the CARTO library and the TORQUE function. The JavaScript libraries of these products are used and adjusted to create the animated maps. The creation of digital and animated maps is one of the possibilities that digital mapping allows and is analysed under the circumstances of perception and change blindness. Mapping theories indicate that new visual variables arise when the maps are created for digital purposes and not only for print only maps. One of these is the blinking that is used for the maps. Next to the blinking variable the maps are created with variation on the aggregation method, spatial resolution, colour use, and size. This results in eighteen visualizations. Three of the visualisation are presented in an usability test to check whether the expectations meet the reality. The test made clear that some maps are better to be used in the identification of the dynamics in an area and others are better to identify a spatial-temporal pattern. The testing of the visualizations leads to the conclusion that: A blinking map can help in the identification of the locations of the dynamics and in the identification of the spatial-temporal pattern. It however still remains a difficult task to use the correct graphic variables to display the development over time. Based on the visualization of the height dynamics a step is made to fill the research gap of the analysis of the dynamics of underwater morphological objects.