Diploma and Master Theses (authored and supervised):
"User-driven Manipulation of Geospatial Data";
Supervisor: E. Gröller;
Institut für Computergraphik und Algorithmen,
A WebGIS is an application designed to store, analyze, manage and present geographical data. It provides tools which support users to explore and understand the underlying data. Depending on the datasource (raster or vector data), these tools are varying. Many more styling options for vector data than for raster data exist. This is because of the position information of vector data which allows the system to apply a wider range of styling features. This thesis is about user-driven manipulation of geospatial data and is part of the ESA DUE Permafrost project. It should help users to navigate through remote sensed data and to explore relevant features of it. Therefore it introduces methods to change the visualization of the data within a WebGIS by assigning different style profiles at runtime. The reference implementation is based on a specific software arrangement. The data is managed by GeoServer, an open source software server with the capability to edit and share geospatial data. To get a visual representation, GeoServer applies a Styled Layer Descriptor (SLD) on the data. A SLD is an XML based language and describes the appearance of associated layers. Modifying the SLD enables to influence the layer appearance. Since the data of the ESA DUE Permafrost project is of type raster only, this work concentrates on tools for styling raster data. As a result of this work, an interactive legend is introduced. It is a user interface and manipulates the SLD at runtime according to the user settings. This gives the user the capability to highlight areas of interest based on the underlying data. The user interface also acts as a color legend for the displayed data.
Electronic version of the publication:
Created from the Publication Database of the Vienna University of Technology.