Karl Rehrl

Assisting Multimodal Travelers: Design and Prototypical Implementation of a Personal Travel Companion

Increasing the share of multimodal journeys is becoming more and more urgent in our society in order to guarantee a high level of mobility in the long term. While car drivers are already assisted by advanced guidance and navigation facilities, continuous on-trip assistance for multimodal travelers is still in its infancy. Especially when it comes to situations of modal change, travelers get discouraged by the increased complexity and the lack of adequate information and guidance. Thus, the goal of our research over the past three years has been to integrate existing information systems and to design and implement the prototype of a digital personal travel companion for multimodal travelers. This paper discusses typical travel situations and possible barriers for people traveling on multimodal journeys. To address these challenges, functional requirements for a personal travel companion are derived from the analysis of the situations. The main sections of this paper describe our results focusing on personalized multimodal journey planning, mobile multimodal trip management, and smart-phone-based pedestrian orientation and guidance in complex public transport transfer buildings

Pedestrian navigation with augmented reality, voice and digital map: final results from an in situ field study assessing performance and user experience

This paper reports on a field study comparing navigation performance and user experience of voice, digital map and augmented reality (AR) interfaces for electronic assistance in the context of pedestrian navigation. The in situ study was conducted with two subsequent experiments in the city of Salzburg along a pre-defined route using a self-implemented smartphone application running on Apples iPhone 4. The study involved 48 participants aged between 22 and 66 years with different experiences in using smartphones and navigation systems. Navigation performance was measured on a micro-level including information on effectiveness (number and reasons of stops, global positioning system (GPS accuracy), efficiency (walking and task completion time, duration of stops) and satisfaction (NASA Task Load Index, System Usability Scale). A final questionnaire completed the study. Between the first and the second experiment, the application was adapted considering user feedback and the previous findings. Results show that in the context of GPS-enhanced pedestrian navigation, digital map and voice-only interfaces lead to significantly better navigation performance and user experience in comparison to AR interfaces. The study also reveals similar results for digital map and voice-only interfaces given that voice instructions are carefully composed. Results lead to the conclusion that AR is still suffering from usability and hardware issues leading to higher uncertainty of navigating persons. Best navigation performance and user experience can be achieved by combining digital maps and accurate voice instructions.

A Conceptual Model for Analyzing Contribution Patterns in the Context of VGI

The chapter proposes a conceptual model as foundation for analyzing user contributions in the context of VGI. The conceptual model is based on a set of action and domain concepts, which are combined to a task-model describing typical tasks of volunteered geographic information contribution. As a proof-of-concept, the model is applied to two sample data sets that are extracted from the OpenStreetMap (OSM) change history. OSM data samples provide a proof-of-concept concerning the applicability of the model for crowd activity analysis. The resulting “contribution graph”, which is a graph-like structure of linked editing actions, can be used as foundation for analyzing complex contribution patterns.

Comparing the effectiveness of GPS-enhanced voice guidance for pedestrians with metric- and landmark-based instruction sets

This paper reports on a field experiment comparing two different kinds of verbal turn instructions in the context of GPS-based pedestrian navigation. The experiment was conducted in the city of Salzburg with 20 participants. Both instruction sets were based on qualitative turn direction concepts. The first one was enhanced with metric distance information and the second one was enhanced with landmark-anchored directions gathered from participants of a previous field experiment. The results show that in context of GPS-enhanced pedestrian navigation both kinds of instruction sets lead to similar navigation performance. Results also demonstrate that effective voice-only guidance of pedestrians in unfamiliar environments at a minimal error rate and without stopping the walk is feasible. Although both kinds of instructions lead to similar navigation performance, participants clearly preferred landmark-enhanced instructions.

An analysis of direction and motion concepts in verbal descriptions of route choices

This paper reports on a study analyzing verbal descriptions of route choices collected in the context of two in situ experiments in the cities of Salzburg and Vienna. In the study 7151 propositions from 20 participants describing route choices along four routes directly at decision points (100 decision points in total) are classified and compared to existing studies. Direction and motion concepts are extracted, semantically grouped and ranked by their overall occurrence frequency. A cross-classification of direction and motion concepts exposes frequently used combinations. The paper contributes to a more detailed understanding of situational spatial discourse (primarily in German) by participants being unfamiliar with a way-finding environment. Results contribute to cognitively-motivated spatial decision support systems, especially in the context of pedestrian navigation.

Assisting orientation and guidance for multimodal travelers in situations of modal change

Increasing the share of multimodal journeys are necessary for society to guarantee a high level of mobility given current growth rates. However, while car drivers are already assisted by advanced guidance and navigation facilities, continuous on-trip assistance for multimodal travelers is still in its infancies. Especially when it comes to situations of modal change, travelers get discouraged by increased complexity and missing information and guidance. Thus, our goal is to develop a palm-based personal travel companion for multimodal travelers. The work presented in this paper especially focuses on pedestrian orientation and guidance in complex public transport interchange buildings.

Digging into the history of VGI data-sets: results from a worldwide study on OpenStreetMap mapping activity

Volunteered geographic information (VGI) data-sets are characterised by heterogeneity due to influences from technical, social, environmental or economic factors. As a result, mapping progress does neither follow a spatially nor a temporally equal distribution, and thus can be hardly measured or predicted. Positively stated, heterogeneity leads to interesting VGI data-sets revealing regional peculiarities such as diverse community activities. This work proposes an approach for identifying regionally and temporally different developments with respect to mapping progress. Regional mapping progress is measured with a modified version of a previously proposed model for classifying activity stages, which has been used as foundation for a massive spatial and temporal analysis of the worldwide OpenStreetMap contributions between the years 2006 and 2013. It also allows the evaluation of rural and unpopulated areas. Results reveal that regional mapping progress heavily depends on a number of distinct influences such as geographical or legal borders, data imports, unexpected events or diverse community developments. The work highlights regions with distinct results by revealing individual mapping stories.

Estimating Completeness of VGI Datasets by Analyzing Community Activity Over Time Periods

Due to the dynamic nature and heterogeneity of Volunteered Geographic Information (VGI) datasets a crucial question isu concerned with geographic data quality. Among others, one of the main quality categories addresses data completeness. Most of the previous work tackles this question by comparing VGI datasets to external reference datasets. Although such comparisons give valuable insights, questions about the quality of the external dataset and syntactic as well as semantic differences arise. This work proposes a novel approach for internal estimation of regional data completeness of VGI datasets by analyzing the changes in community activity over time periods. It builds on empirical evidence that completeness of selected feature classes in distinct geographical regions may only be achieved when community activity in the selected region runs through a well-defined sequence of activity stages beginning at the start stage, continuing with some years of growth and finally reaching saturation. For the retrospective calculation of activity stages, the annual shares of new features in combination with empirically founded heuristic rules for stage transitions are used. As a proof-of-concept the approach is applied to the OpenStreetMap History dataset by analyzing activity stages for 12 representative metropolitan areas. Results give empirical evidence that reaching the saturation stage is an adequate indication for a certain degree of data completeness in the selected regions. Results also show similarities and differences of community activity in the different cities, revealing that community activity stages follow similar rules but with significant temporal variances.

Action and interaction in volunteered geographic information: a workshop review

This paper presents a summary of the Action and Interaction in Volunteered Geographic Information international workshop which was held as a one day pre-conference workshop to the 16th Annual Association of Geographic Information Laboratories in Europe conference in Leuven, Belgium in May 2013. This paper summarises the important outcomes of workshop presentations and key discussion statements from participant contributions to an open-floor discussion on the most pertinent issues in Volunteered Geographic Information (VGI) research. Participants engaged this discussion focused on what are the most likely problems which could form the basis for a research agenda in VGI composed of both short- and long-term research objectives. While the development of a VGI research agenda will require the involvement of the broadest possible spectrum of disciplines, this paper is, none-the-less, an important first step on this journey.

Deriving driver-centric travel information by mining delay patterns from single GPS trajectories

Crowd-sourcing approaches for generating accurate real time travel information for road networks is promising but still challenging. For example, travel speeds, even if derived from highly sampled GPS trajectories, have limitations in their interpretability for more sophisticated travel information such as traffic-related delays or level of service (LOS) information. The proposed algorithm in this work analyzes the flow characteristics of individual vehicles by deriving and classifying delays into LOS relevant (e.g. queuing traffic) and LOS non-relevant delay patterns (e.g. stopping at a crosswalk). In contrast to other approaches, the proposed algorithm works on single GPS trajectories collected from individual vehicles (e.g. floating car data - FCD), without the necessity to average travel speeds or travel times of multiple vehicles for reliable LOS estimation. Applied to sample GPS trajectories from test drives the algorithm reaches an overall recognition rate of 82.0% for delay classes slight delay, massive delay, single stop, and multi stops. The recognized delay patterns are capable to distinguish between LOS relevant and LOS non-relevant delays at high accuracy for subsequent delay and LOS information. The recognition of LOS non-relevant single stops reaches a rate close to 100.0%.