From static to dynamic visualization of the sea surface height on a web GIS application

During the last three decades, the Earth’s climate is changing rapidly, with higher average temperatures every year that leads not only to the melting of the ice sheet in the arctic and on most of the glaciers all over the world but also to extreme weather phenomena. The rise of the temperature can affect the Sea Surface Height (SSH) in more than one way, and since 70% of the Earth’s surface is covered by the oceans, if the oceans are being affected then the whole Earth also is. The monitoring of the SSH can help the scientist predict the changes that will take place in the future. The SSH is a dynamic phenomenon that constantly changes not only within different decades but also from year to year, month to month even within the same day. These changes are the result of various phenomena and are called anomalies. When the SSH is monitored different phenomena are represented in different time scales and it is important to be taken into consideration if there is the need for a proper understanding of the SSH phenomenon. Many spatial data vendors are providing a large number of data-sets related to the monitoring of SSH and its anomalies and as a result, there is the need to find the most effective way to extract information from the data. Over the years has been established that one of the most effective ways to extract information from data is through the various visualization techniques and since the data of SSH is mainly spatial the main visualization technique is cartography. The advancements of the technology over the last couple of decades have led to a reality that the ”online” application is the norm and consequently the web mapping and web geographical information system (GIS).The goal of this thesis is to propose an architecture for a web GIS application that will be able to visualize dynamic data while adding elements of interactivity to improve the chances of the Sea Surface Height Anomaly (SSHA). IN order to achieve the goal of this thesis three main research questions need to be answered: What type of animation should be used (in order to visualize the passing of time), what interactivity elements should be added (e.g. zooming/panning in space and time) and what system’s architecture is optimal for such application (server-side/client-side etc.). This document is providing guidelines on how to create such an application and is resulting in the production of a prototype. The first part of this thesis is the review of the main ideas that are introduced in this project and how they were implemented by other researchers. Then, a comparison between the different implementation techniques (for every research question) is taking place to determine the main characteristics of the application. The final part is related to the implementation of the chosen techniques that lead to the development of the prototype application. The resulted prototype even though it is not perfect, due to technical limitations that were a consequence of implementing some of the most recent concepts in web development, is functional and paves the way for the development of new improved dynamic/interactive web GIS applications (https://giorgosdimo.github.io/MSc-Thesis/).Geomatic

Data analysis, processing and interpretation from different sources: satellites, ground sensor, citizens measurements and municipalities, to fight against building subsidence

Every day, terabytes of information is generated, filling storage devices around the world. However,the human brain have limited capacities to read and understand raw data from a computer screen.That is why data specialists need to ingeniously create better ways to display, process and analyzemassive amounts of data.Our research project is not about avoiding subsidence, not even about cracks on buildings; it ispurely data analysis and interpretation. This study will help professionals understand and fightagainst building subsidence. Our task was to create, manipulate and make sense of charts like theone below (a real line graph from InSAR data), then translate them into useful information forstakeholders in the local, national and global community.The aim of the project was to understand if ground sensor technologies are comparable to othersources of information. In our analysis different strategies to analyze building subsidence wereimplemented, e.g. homogeneous subsidence, heterogeneous subsidence and for water levels,interpolation and cross correlation methods. In addition, other techniques like sensor fusing wereimplemented to compare data from different sources.As a result from all these strategies, we can say that the water level sensors placed in our researchbuilding, have a high similarity with citizens and municipality data. In contrast, InSAR data is notcomparable with the subsidence sensors placed in the building because they have differentreferences and the period of study was too short to get accurate results from satellite data. Finally,an idea for future implementation strategies was proposed. On this idea, measurements of levelscan be carried out taking as a reference the NAP level and comparing the subsidence between ahealthy-foundations building and another one with wooden-piles foundation.Synthesis Project 2018Geomatic