Papers by Melitta Dragaschnig
Fast Hidden Markov Model Map-Matching for Sparse and Noisy Trajectories
2015 IEEE 18th International Conference on Intelligent Transportation Systems, 2015
Generierung detaillierter Geschwindigkeitsprofile aus grob aufgeloesten Floating-Car-Daten
Oesterreichische Zeitschrift Fuer Verkehrswissenschaft Oezv, 2013
Lecture Notes in Geoinformation and Cartography, 2014
As a result of OpenStreetMap's (OSM) openness and wide availability, there is increasing interest... more As a result of OpenStreetMap's (OSM) openness and wide availability, there is increasing interest in using OSM street network data in routing applications. But due to the heterogeneous nature of Volunteered Geographic Information (VGI) in general and OSM in particular, there is no universally valid answer to questions about the quality of these data sources. In this paper we address the lack of systematic analyses of the quality of the OSM street network for vehicle routing and the effects of using OSM rather than proprietary street networks in vehicle routing applications. We propose a method to evaluate the quality of street networks for vehicle routing purposes which compares relevant street network features as well as computed route lengths and geometries using the Hausdorff distance. The results of our case study comparing OSM and the official Austrian reference graph in the city of Vienna show close agreement of one-way street and turn restriction information. Comparisons of 99,000 route pairs with an average length of 6,812 m show promising results for vehicle routing applications with OSM, especially for route length computation where we found median absolute length differences of 1.0%.
Assessing traffic performance using position density of sparse FCD
ABSTRACT We present an approach for evaluating traffic performance along corridors and its variat... more ABSTRACT We present an approach for evaluating traffic performance along corridors and its variation based on floating car data (FCD). In contrast to existing work, our approach can cope with long and irregular FCD reporting intervals. Resampling of sparse FCD in time and interpolation increases spatial resolution of FCD positions along the corridors. FCD position density is computed with a uniform kernel, which leads to traffic performance expressed as average travel time per meter and average speed. Experimental results based on real-world FCD for a freeway section and arterial roads in Vienna illustrate the plausibility of the approach, and an example illustrating our approach before and after a traffic influencing measure shows its advantage over using dedicated probe vehicle runs, temporary sensor installations or human observers. A sensitivity analysis provides guidelines for the important parameters.
GI_Forum 2014, 2014
Reliable energy estimation methods are a very important step to address the range anxiety problem... more Reliable energy estimation methods are a very important step to address the range anxiety problem of electric vehicle adoption. Besides driving patterns and vehicle parameters, geographic information about elevation changes is one of the most important pieces of information to predict energy consumption. This paper presents a method to assess the impact of digital elevation model (DEM) quality on energy consumption estimation for electric vehicle routes. We demonstrate the use of this method by applying it to compare energy consumption estimates for 16,500 randomly generated routes based on three recently released open DEM datasets: NASA Shuttle Radar Topographic Mission (SRTM) version 3.0, EU-DEM and open government DEM data provided by the city of Vienna. Results show that energy consumption models tend to overestimate route energy consumption by a mean error of 2.9% and 15.8% respectively when lower-resolution DEMs are used to compute route elevation profiles. A spatial analysis of the error distribution shows that the mean error varies between different regions within the analysis area with bigger error values in the hills and in the city centre indicating that highresolution elevation data is not only important in hilly and mountainous areas but also in dense urban environments.
Transactions in GIS, 2013
This paper presents a novel open source toolbox for street network comparison based on the Sextan... more This paper presents a novel open source toolbox for street network comparison based on the Sextante geoprocessing framework for the open source Geographic Information System Quantum GIS (QGIS). In the spirit of open science, the toolbox enables researchers worldwide to assess the quality of street networks such as OpenStreetMap (OSM) by calculating key performance indicators commonly used in street network comparison studies. Additionally, we suggest two new performance indicators for turn restriction and one-way street comparisons specifically aimed at testing street network quality for routing. We demonstrate the use of this toolbox by comparing OSM and the official Austrian reference graph "Graph Integration Platform" (GIP) in the greater Vienna region.
The use of Floating Car Data (FCD) systems for the generation of traffic information has been dis... more The use of Floating Car Data (FCD) systems for the generation of traffic information has been discussed in numerous publications, many of which are based on simulated data or on a small number of vehicles collecting data over a limited time span. We present FLEET, a real-world FCD system, which has been continuously operating since 2003, collecting data from thousands of taxis in the Vienna region. We describe the system capabilities, our operating experience, and selected applications accumulated over the past years.
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Papers by Melitta Dragaschnig