Graduates

 

   

  Dr. Ivan Tomljenovic

PhD-Thesis: Transferable and Robust Building Extraction from Airborne Laser Scanning Data using Object-Based Image Analysis Paradigm (October, 2016)

In my PhD thesis I investigated use of Object-Based Image Analysis for the Airborne Laser Scanning Point Cloud data. The main goal of my research was to extract building outlines in and automated and robust way. Initially, a overview of an existing building extraction approaches has been made,  followed by the generation of a  prototype single-click solution in order to obtain initial spatial data in an automated manner. Obtained results were tested for their appropriateness in two separate cases: building type identification using random forest statistical approach and ISPRS Benchmarking. In both cases the results provided satisfying response (above 90%). The approach was additionally improved between the two use case scenarios. Final work provided additional analysis of the stability of the developed solution. The core result provided a rule-based solution for an automated building outline extraction from the ALS data based on the application of OBIA methodology.  

 

  Dr. Christian Neuwirth

PhD-Thesis: Evolution of space in System Dynamics simulations (May, 2016)

In my PhD thesis I studied the influence of Spatial Structural Feedbacks (SSF) on the behavior of complex systems and developed a tool for simulating SSF. Effects of SSF can be observed in a multitude of system types, ranging from natural to anthropogenic and from microscopic to global scales. They all have one thing in common: Processes (e.g. the flow of water) reshape spatial structure (e.g. the earth’s topography), which in turn affects the process (e.g. the flow of water). Among other things, results indicate a balancing effect of SSF. Neglecting those effects in computer-based simulations of real-world phenomena causes an overestimation of a system’s self-enforcing capacities, runaway behavior and exponential growth or decline.

   

Dr. Peter Ranacher

PhD-Thesis: GPS movement analysis: measurements, similarities and patterns (March, 2016)

In my PhD thesis I aimed to quantify the influence of error when recoding movement with a GPS. GPS movement data are affected by two types of error, measurement error and interpolation error. Both errors can significantly influence knowledge extraction from movement data. However, appropriate methods to assess the influence of error on real-world movement data are still lacking. This thesis introduces such measures for both measurement and interpolation error. The second aim was to develop a model to study the energy-efficiency of cars in an urban road network. This model analyses a car's movement patterns recordedwith the GPS and estimates how energy-efficiently the car is moving.

 

Dr. Ourania Kounadi

PhD-Thesis: Geospatial Privacy Framework for Confidential Discrete Data with Emphasis on Spatial Crime Analysis & Visualisation (August, 2015)

In my PhD thesis I aimed to understand the risks, trends, and opinions on location privacy. Existing protection methods for confidential discrete location data as well as published warnings about disclosure risk were reviewed. Furthermore, the public’s perception on location privacy in the particular context of crime mapping was collected through interviews and further analyzed. Also a basis was created to achieve the second aim of this thesis, which is to offer cartographic display guidelines when crime data are presented on public maps or disseminated among stakeholders. The results are scientifically innovative and highly relevant for the work of Law enforcement agencies like the Bundeskriminalamt.

   

Dr. Günther Prasicek

PhD Thesis: Morphometric analysis of alpine topography conditioned by tectonic uplift and glaciation (August, 2015)

In my PhD thesis I developed geomorphometric tools to extract information about the distribution and persistence of glacial topography from digital terrain models. The distinct geometry of U-shaped glacial and V-shaped fluvial valleys facilitates the automated identification of glacial valley cross sections and the quantification of glacial imprint. A multi-scale curvature approach is used to fit the analysis scale to valley width and to subsequently extract valley cross-sections. Power-laws are fitted to the extracted transects to quantify valley shape. This procedure allows for the automated, efficient and objective analysis of extended mountain areas.

The results of a worldwide analysis of prominent mountain ranges indicate that the lifespan of glacial topography in Earth’s most rapidly uplifting mountain ranges is on the order of one interglacial period, preventing the development of a cumulative glacial signal over multiple glacial cycles. In contrast, in most alpine landscapes more than 100 kyr are required for the transformation from glacial back to fluvial topography and glacial landforms have not or have only partially been erased during the current interglacial.

   

Dr. Thomas J. Lampoltshammer

PhD-Thesis: Natural Language-based Modelling, Processing, and Interaction
in Geographic Information Systems (July, 2015)

The focus of my thesis is the evaluation of the applicability of natural language-based approaches and methods within the following three major functional dimensions of geographic information systems, namely modelling, processing, and the interaction of geo-referenced information. The presented research work contributes to the research area of semantic knowledge engineering using ontologies within geoinformatics applications. It is demonstrated how ontologies can be used to facilitate the modelling of expert knowledge for an efficient model-based classification of real-world entities. In addition, how ontologies can be employed as a means of natural language-based proxies to interact with expert systems is demonstrated.

My research further analyses implicit and explicit geo-referenced information in the form of social media data and demonstrates how these data sets can be used to discover tangible and intangible infrastructure within social structures. Furthermore, it is elaborated how natural language-based processing methods and tools can foster the functionalities of geographic information systems such as geocoding or reverse geocoding.

 

 

 

Dr. Eva Haslauer

PhD-Thesis: GIS-based backcasting: An innovative method for parameterisation of sustainable spatial planning and resource management (July, 2015)

In my Doctoral Thesis I developed a GIS-based, spatially explicit backcasting model. Backcasting was conceptually developed in the 1970s as a planning method for electricity supply and demand and to support sustainable decisions in the energy sector. At this time it was called “backwards looking analysis”. Backcasting, as a decision support model, starts from an desired future goal and works backwards until the present state is reached. The future goal is often a vision describing a desired future scenario. During the backwards development milestones are set. They are small interim scenarios along the inverse way between the present state and the future scenario which is usually

20 to 50 years ahead. The milestones shall reveal how to achieve the desired future scenario step by step. The backcasting model is implemented with Python and applied to a case study of urban sprawl in Salzburg, Austria. The results of the model show a back-casting of land use classes from a future state back to the present, in 10 year time steps. This can be utilized to counteract urban sprawl and its negative consequences by supporting spatial planners to derive long-term strategies for sustainable spatial developments in the case study area.

   

Dr. Sebastian d'Oleire-Oltmanns

PhD-Thesis: Gully mapping on multiple scales based on UAV and satellite data (December, 2014)

In my dissertation I present methods for gully mapping on two different scales. The small scale level is based on Small Format Aerial Photographs (SFAP) acquired with an Unmanned Aerial System (UAS). The large scale level is based on high resolution optical satellite data (QuickBird-2).

In addition to the traditional field investigations carried out in geomorphology, remotely sensed data acquired at different scales covers various possibilities to analyze a specific study site, the broader spatial context around this study site (e.g. catchment level) and finally enables area-wide mapping of gully-affected features. Several workflows were developed and applied: a workflow for photogrammetric processing of SFAP data, the concept of object-based image analysis (OBIA) was applied at two different (spatial) scale levels for the detection of gullies and gully-affected areas and further analysis of the DSM provided estimations on the total soil loss for a specific gully as well as for the catchment level.

 

   

Dr. Michael Hagenlocher

PhD-Thesis: Integrated spatial indicators for modeling, exploring and visualizing vulnerability to vector-borne diseases (December, 2014)

My dissertation presents novel concepts, methods and tools for the spatial assessment of social vulnerability to vector-borne diseases (VBDs) at different spatial scales. The focus was placed on modeling spatial variations in vulnerability of the population to two mosquito-borne diseases, malaria and dengue. Study areas include Santiago de Cali, Colombia (local scale) for dengue, as well as Tanzania (national scale) and the five member states of the East African Community (regional scale) for malaria. To evaluate the robustness of the results in regards to changes in the input parameters, a GIS tool for sensitivity analysis is presented which was used to assess the impact of indicator selection and indicator weights. A web-based tool is proposed which enables users to visualize and explore the results in an interactive manner. By indicating vulnerability ‘hotspots’ and simultaneously highlighting the contribution of the single vulnerability indicators for the respective region, the tool enables decision makers to prioritize intervention areas and to target appropriate interventions. It is therefore anticipated that the concepts, methods and tools proposed in this dissertation can make a valuable contribution to reducing prevailing vulnerabilities and strengthening resilience of the population to VBDs in the study areas, and act as a role model for future assessments.

   

Dr. Mariana Belgiu

PhD Thesis: Formal ontologies for extracting information from remotely sensed data (June, 2014)

My PhD thesis is a contribution to bridging the semantic gap between low-level information extracted from remotely sensed data and high-level user concepts. It proposes a classification protocol which combines data-driven segmentation approach with formal ontologies of target classes. Ontologies have been successfully applied to classify urban building types, land cover classes defined by Food and Agriculture Organization of the United Nations (FAO/UN) and land cover classes defined by the Austrian Environmental Agency within the Land Information System of Austria (LISA) from remotely sensed data. Land cover and building type ontologies are extended with descriptive information detectable in remotely sensed data by using image interpretation keys, supervised classifiers such as Random Forest, and by using common sense knowledge gained so far for mapping urban buildings and land cover classes in urban/suburban environments. The developed ontologies can be easily integrated into other knowledge infrastructures dedicated to information sharing and integration in a distributed way.

 

   

Dr. Bakhtiar Feizizadeh

PhD-Thesis: An Object-Based Workflow for Integrating Spatial Scale and Semantics to Derive Landforms from Digital Elevation Models (May, 2014)

My main research interests include methodological issues in geoinformatics, integration of GIS and Remote Sensing for land use/cover monitoring, land suitability analysis, geohazard and risk assessment, in particular landslide mapping. I have practiced developing methodology for GIS based Multicriteria Decision Anlysis (GIS-MCDA), modelling sensitivity and uncertainty in GIS environment, Object Based Image Analysis (OBIA) and thermal Remote Sensing image processing. I have teaching experiences in both Remote Sensing and GIS.

 

   

Dr. Clemens Eisank

PhD-Thesis: An Object-Based Workflow for Integrating Spatial Scale and Semantics to Derive Landforms from Digital Elevation Models (June, 2013)

In my PhD thesis I proposed a two-phased semi-automated workflow that allows for more objective mapping of landforms in Object-Based Image Analysis (OBIA) based on Digital Elevation Models (DEMs). The workflow integrates methods for detecting ‘characteristic scales’ of segmentation-derived terrain object patterns (Phase 1), as well as explicit representations of the common sense geomorphological landform knowledge (Phase 2). These knowledge models support the selection of representative operational features for semantics-based classification of landforms at detected scales. The workflow was successfully applied to derive two distinct types of glacial landforms from DEMs: cirques and drumlins. A third test on extracting gullies in aerial photographs showed that the workflow can potentially be transferred to non-glacial landforms, and to other data types with various spatial resolutions. The proposed workflow ensures that landform mapping is conducted at representative terrain object scales and that objective geomorphological landform knowledge is integrated. In comparison to previous approaches landforms are mapped more objectively, and thus it is expected that the workflow may become a standard in geomorphometry.

 

 

Dr. Günther Sagl

PhD-Thesis: Spatio‐Temporal Analyses of Environmental and Social In Situ Sensor Data (December, 2012)

In my dissertation I investigated dynamics and relationships of some environmental and social phenomena on the basis of such sensor data using interdisciplinary analysis methods linked with GIScience. Specifically, I enhanced a service‐oriented geo‐analysis workflow that facilitates near real‐time environmental monitoring and time-critical decision support; I analysed collective human behaviour patterns derived from user‐generated data in mobile networks or social media to better understand the “pulse” of dynamic urban systems; I developed the novel “context‐aware analysis approach”, which comprises several (statistical) analysis methods, to explore spatial, temporal and periodical relationships between the weather and collective human activity – thereby providing insights into environment‐human interface aspects. The outcomes of my PhD research can therefore provide a basis for further interdisciplinary investigation towards the development of an adaptive framework for real‐time monitoring and modelling of environment-human feedback loops.

Currently I am working as a PostDoc Researcher in the GIScience Research at the University of Heidelberg, where I am involved in several fascinating and challenging projects somehow related to my PhD topic.