Question Based Analysis


Rogier Meerlo defended his MSc thesis

Congratulations to Rogier Meerlo who successfully completed and defended his MSc thesis titled “The relevance of semantics for GIS workflow synthesis“. You can find the abstract below.


In order to solve geo-analytical problems users of GIS must often compose workflows in GIS software. In order to do so, the user must be aware of the possible functionalities and which tools can be connected in a meaningful way in order to obtain their goal. A proposed solution for assisting GIS users in creating meaningful workflows is the creation of a GIS workflow synthesis engine. This type of support system would allow users to automatically generate a workflow capable of bridging the gap between the available data and the goal specified by the user. The main objective of this thesis is the creation and evaluation of an ontology-based GIS workflow synthesis prototype. This goal was achieved by formalizing the semantic data type ontology and annotating tools and datasets using semantic web technologies. These technical elements were combined in a workflow synthesis engine in order to create a functional GIS workflow synthesis prototype. The quality of such a workflow synthesis system was evaluated by generating workflows for five geo-analytical questions and evaluating each of the first 20 workflows by hand in accordance with a novel workflow evaluation framework. This process was repeated with a limited workflow synthesis prototype that could only take traditional GIS semantics into account in order to provide a reference for the capacity of the semantic data type ontology. The work done within this thesis has proven that a GIS workflow synthesis prototype based on the semantic data type ontology has the potential for creating meaningful workflows, and has a higher capacity for answering spatial questions than a synthesis engine based on the traditional semantics of line, points, polygons, vectors, and rasters.