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Another interesting GIScience talk is coming up this week. We cordially invite you to the GIS colloquium:

28.01.15, 11.15am Lecture Hall Berliner Straße 48: Enhancing IR by Adding Geographical Information: Text- and Geo-based Search within a Corpus of Literary Textspresented by Bastian Entrup.

Feel free to find more detailed information under http://www.geog.uni-heidelberg.de/gis/veranstaltungen.html

GPS data uploaded to the OpenStreetMap servers is a popular example of what is called Volunteered Geographic Information (VGI). The data has been (and is still) collected by the project contributors primarily to support mapping. As the inclusion of roads and paths in the map is a major goal of the project, the collected GPS data often follows such man made structures. It has already been shown that a set of GPS tracks following the same way can even be used to derive the centrelines of the respective ways (cf. e.g. [1], [2], [3], [4]).

Current feature extraction approaches focus on the horizontal coordinates contained within the GPS tracks. The reasons for that are that the horizontal information is sufficient for many purposes, GPS elevation measurement is less precise than horizontal measurements, and (particularly in the context of VGI) the elevation information is not always provided in GPS data collected by low-cost GPS receivers. However, there are scenarios such as route planning for bicycles, electric cars and wheelchairs where the vertical component of ways is very important. As we are currently working on route planning for people with limited mobility in the CAP4ACCESS project, this is a relevant topic for our group. Moreover, we want to continue some of our previous research in the area of 3D routing (cf. Schilling et al. 2008).

We therefore want to test whether the elevation information contained in the GPS tracks collected by the OpenStreetMap contributors can serve as a low-cost approach for deriving the incline of roads and paths. For this purpose, we have extracted GPS points from the regional extracts of the planet.gpx files (Many thanks to our student assistant Steffen John!).

A first analysis showed that in the Heidelberg region there are about 1,000 GPS tracks (using the 2013 planet.gpx dump). About 90% of the tracks in Baden-Württemberg (compared to e.g. only ~65% in Bremen) have elevation information. There are ~1,000,000 individual GPS points in Heidelberg. The bounding box that was applied has a size of ~200km². This means that on average there is one point per 200m² which equates to one point per 15m*15m (assuming the points would be evenly distributed). However, as can be seen in the visualisation, in practice the point density in the regions of our interest (i.e. in the proximity of at least some of the roads and paths) is much higher with the drawback of an otherwise low coverage.

The visualisation of the point cloud has been prepared using WebGL and the JavaScript library three.js - proceeding some of our earlier WebGL mapping efforts, e.g.: traffic flow visualisation for London, Twitter Point Clouds, webgl.uni-hd.de. As the performance depends on your machine and the speed of your internet connection, we have prepared different versions, including different numbers of points.

~100k points
~350k points
~1M points

(There may be some issues when using Firefox and Internet Explorer - we recommend Google Chrome for viewing)

We call for papers for the Workshop:

RICH-VGI: enRICHment of volunteered geographic information (VGI):
Techniques, practices and current state of knowledge

Workshop @ the 18th AGILE Conference on Geographic Information Science

Lisboa, Portugal.
Tuesday 9 June 2015

In recent years we have witnessed the rapid emergence of olunteered Geographical Information (VGI) projects. VGI is being applied more and more for research and applications. Nevertheless, VGI is often denounced due to its heterogeneities in quality, completeness and redundancy. However, these can be improved by applying spatial analysis and data mining techniques. These approaches utilize the relationship between the data from a VGI platform itself and/or cross-utilization of data from other sources, including other VGI platforms or authoritative sources. The purpose of this workshop is to intensively discuss the possibilities of data derivation, knowledge propagation and quality improvement for VGI and VGI analysis.

Examples of topics of particular interest include:
• Enrichment and quality assessment of VGI
• Techniques of matching data sets from different VGI platforms
• Techniques and applications of generating 3D terrain and 3D buildings from VGI
• Enrichment of attributive information for VGI
• Improvement of data quality and quantity from VGI by standardization of data structures
• Innovative data mining and data fusion algorithms adaptable for VGI
• Enhanced VGI analytics that relies upon different data sources (both authoritative and non-authoritative)
• Enrichment and assessment of VGI considering the needs of particular application domains (e.g. environment, routing, disaster management, urban planning, etc.)
• and other similar topics
We invite several kinds of contributions: full research papers presenting new work in the indicated areas, technical applications and case studies, as well as innovative insights.

The objective of this workshop is to provide an interdisciplinary forum towards determining techniques and ideas for improving VGI in order to derive further information from it for different use cases and VGI analysis. These techniques and ideas include several aspects of data quality, such as completeness, attributes, locational accuracy, metadata, etc

The workshop shall encourage:

  • Discussions and exchange of research experiences, approaches, and algorithms for enriching VGI data,
  • Understanding the state of the art in the area of VGI enrichment,
  • Identifying current knowledge gaps which will help us to clearly outline some short-term and long-term VGI enrichment research goals and themes.

Format of the Workshop
It will be a full day workshop. The workshop will include keynote speeches, a number of oral presentations in three sessions, a session of technical demonstration and a session of panel discussion.

Organizing Committee
Dr. Hongchao Fan
Dr. Jamal Jokar Arsanjani
Dr. Peter Mooney
Prof. Dr. João Porto de Albuquerque
Prof. Dr. Alexander Zipf

Call for Papers
We invite submissions of short papers (maximum 2,000 words) according to AGILE formatting guidelines (Springer Word Document Template or the Springer Latex Document Template).
The papers will be published online.
In addition to this we shall pursue the potential for the publication of a special issue in an appropriate international journal
Please send the manuscripts as word or pdf files to richvgi@geog.uni-heidelberg.de

Submission of short paper: April 07 2015
Notification of Acceptance and Review feedback: May 04 2015
Revised Version of Paper for Publication on WebSite: June 01 2015
Workshop date: June 09 2015

Programm Committee
To be announced

Further information will be posted at the Workshop Homepage:

Here is the “call for Paper PDF.“.


Children between the age of 9-12 years have the opportunity to attend a practical workshop at the Institute of Geography within the framework of the KinderUni Heidelberg (Young University) on Saturday, 07.02.2015. In this workshop “OpenStreetMap- die offene Weltkarte. Mach’ mit und werde ein Mapper!” the pupils will get to know OpenStreetMap and Citizen Science via a general introduction and different mapping activities.

Major research efforts have so far dealt with OSM data quality analysis, but the modality of the evolution of OpenStreetMap (OSM) across space and time has been barely noted. Therefore, a new study by Jokar Arsanjani et al. that has recently been accepted for publication in Transactions in GIS aims to analyze spatio-temporal patterns of contributions in OSM by proposing a contribution index (CI) in order to investigate the dynamism of OSM by considering a per cell analysis of the nodes quantity, interactivity, semantics, and attractivity (the ability to attract contributors). Additionally, this research explores whether OSM has been constantly attracting new users and new contributions, or if OSM has experienced a decline in its attractivity. Using the Stuttgart region of Germany as a case study, the empirical findings of the CI over time confirm that since 2007, OSM has been constantly attracting new users, who create new features, edit the existing spatial objects, and enrich already available ones with attributes. This rate has been dramatically growing since 2011. The utilization of a Cellular Automata-Markov (CA-Markov) model provides indications that by the end of 2016 and 2020, the rise of CI will spread out over the study area and only a few cells without OSM featues shall remain.

Jokar Arsanjani, J., Mooney, P., Helbich, M., Zipf, A., (2015; accepted): An exploration of future patterns of the contributions to OpenStreetMap and development of a Contribution Index, Transactions in GIS. Wiley. (accepted 2014).

Transactions in GIS

The DFG research project Urban Emotions was mentioned in an interview of the regional newspaper Rhein-Neckar-Zeitung (in German only). The project aims at the development of a methodology to extract contextual emotional information for spatial planning based on real-time people-as-sensors and crowdsourcing approaches within social media. It is a collaborative project between ZGIS Salzburg University, the GIScience Research Group Heidelberg University and the TU Kaiserslautern (Regional & Environmental Planning). The goal is to analyse the trends of real-time human sensory and crowdsourcing approaches in social networks for the extraction of contextual emotion information for decision support in spatial planning and to develop it further to an innovative methodology for the domain of urban and regional planning. This methodology includes the correlation between emotions extracted from psycho-physiological smartband sensor measurements and different VGI and Social Media datasets (Twitter, Instagram, Flickr, etc.). Herein, the topics of data privacy and handling personalised data are inherently considered.

Urban Emotions GIScience Heidelberg University

In this weeks BrownBag talk at the UCSB Spatial Center Dr. Andrea Ballatore gave a nice overview about vandalism in user generated geographic information. The talk referred to his recent paper on “Defacing the Map: Cartographic Vandalism in the Digital Commons“. There he outlines a typology of different kinds of map-based vandalism through a qualitative analysis of reported incidents in WikiMapia and OpenStreetMap. He also mentioned that our paper on detecting vandalism in OpenStreetMap is still the only automated approach of investigating this interesting issue. The resulting system “OSMPatrol” by Neis et al. (2012) is a rule-based approach that detects suspicious behaviour of editing patterns in OpenStreetMap taking the reputation of mappers into account. For example later work analysed contribution to OSM in several regions all over the world.

Neis, P.; Goetz, M.; Zipf, A. (2012): Towards Automatic Vandalism Detection in OpenStreetMap. ISPRS Int. Journal of Geo-Information, 1, 315-332.

The special issue on “GeoWeb 2.0″ of the ISPRS International Journal of Geo-Information with guest editors Alexander Zipf and Bernd Resch (both GIScience Research Group, Heidelberg University) is online and can be found here (Open Access).
The special issue aims at exploring new trends in how the production and usage of geographic information are being transformed through the changes being induced by new Web technologies and their shifting usages. It contains five papers dealing with different aspects of Volunteered Geographic Information (VGI) and OpenStreetMap (OSM).


In contrast to photo-based VGI (e.g. Flickr) the correlation between the place where an information has been created and what the information is about is less intuitive for text-based VGI. In order to gain more insight into the relationship between text information generated in mobile contexts (e.g. via smartphones) and their recorded location, research has been conducted using the example of of microblogging texts (tweets) produced on mobile devices.

For the purpose of this research, tweet topics were correlated to areas. In doing so, classified points of interest from OpenStreetMap served as validation points. The classification and geolocation of these points was adopted to correlate with tweet content by means of manual, supervised, and unsupervised machine learning approaches. Evaluation showed the manual classification approach to be highest quality, followed by the supervised method, and that the unsupervised classification was of low quality.

Regarding the initial research goal, it was found that the degree to which tweet content is related to nearby points of interest depends upon topic (that is, upon the OpenStreetMap category). A more general synthesis with other research leads to the conclusion that the strength of the relationship of tweets and their geographic origin also depends upon geographic scale of the respective analysis, where correlations found by large scale analyses are more significant than those found by small scale analyses. This finding highlights the crucial importance of considering scale in Twitter analyses. This has also been highlighted in another recent article from our group (multi-scale nature of the Twitter dataset). Moreover, events and also photos included in the microblogging-texts seem to increase the location-content correlation.

In the scope of this research we are happy to announce a paper that has recently been published open access in the Journal of Spatial Information Science (JOSIS).


Hahmann, S., Purves, R.S. & Burghardt, D. (2014): Twitter location (sometimes) matters: Exploring the spatial relationship between georeferenced Tweets and feature classes, Journal of Spatial Information Science. iss. 9, pp. 1–36

Hahmann, S. (2014): Zur Beziehung von Raum und Inhalt nutzergenerierter geographischer Informationen. PhD thesis (in German), TU Dresden.

We whish you the most happy and successfull New Year!
Now you can follow the news from our GIScienceBlog about recent results and activities in Geoinformatics and GIScience also via Facebook or Twitter - just as you prefer. Hope you like it ;-) Of course you still can use the RSS-Feed, too.
Enjoy reading.

All the best for 2015, yours
GIScience Research Group Heidelberg University

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