Abstract

International audience; This chapter aims at understanding the place of users in the online discussions between Openstreetmap contributors who map cycling infrastructures. Drawing on an analysis of the mailing list of the French forum of Openstreetmap, we show that contributors deal with different kinds of users' instantiations. We describe how these contributors try to avoid any attachement to one or another category of users, which would threaten their ideal of "universality".

Abstract

Abstract. A significant advantage of OpenStreetMap data is its up-to-dateness. However, for rural and city planning, it is also of importance to access historical data and to compare the changes between new and old versions of the same area. This paper first introduces into a differentiated classification of changes on OpenStreetMap data sets. Then a methodology for an automated database-supported analysis of changes is presented. Beyond the information already provided from the OpenStreetMap server, we present a more detailed analysis with derived information. Based on this approach it is possible to identify objects with attributive or geometric changes and to find out how they exactly differ from their previous versions. The analysis shows in which regions mappers were active during a certain time interval. Furthermore, a time based approach based on various parameters to determine the quality of the data is presented. It provides a guideline of data quality and works without any reference data. Therefore, an indication about the development of OpenStreetMap in terms of completeness and correctness of the data in different regions is given. Finally, a conclusion and an outlook on open research questions are presented.

Document type: Article

Abstract

Natural disasters like floods are a worldwide phenomenon and a serious threat to mankind. Flood simulations are applications of disaster control, which are used for the development of appropriate flood protection. Adequate simulations require not only the geometry but also the roughness of the Earth’s surface, as well as the roughness of the objects hereon. Usually, the floodplain roughness is based on land use/land cover maps derived from orthophotos. This study analyses the applicability of roughness map derivation approaches for flood simulations based on different datasets: orthophotos, LiDAR data, official land use data, OpenStreetMap data and CORINE Land Cover data. Object-based image analysis is applied to orthophotos and LiDAR raster data in order to generate land cover maps, which enable a roughness parameterization. The vertical vegetation structure within the LiDAR point cloud is used to derive an additional floodplain roughness map. Further roughness maps are derived from official land use data, OpenStreetMap and CORINE Land Cover datasets. Six different flood simulations are applied based on one elevation data but with the different roughness maps. The results of the hydrodynamic–numerical models include information on flow velocity and water depth from which the additional attribute flood intensity is calculated of. The results based on roughness maps derived from LiDAR data and OpenStreetMap data are comparable, whereas the results of the other datasets differ significantly. Document type: Article

Abstract

These slides (in Italian) were presented during the FOSS4G-IT 2017 conference, held in Genova (Italy) on February 9-10, 2017 (http://www.dicca.unige.it/geomatica/foss4git_2017/index.html). The presentation is about the exploitation of OpenStreetMap (OSM) database in the emergency stage and focuses on the activities of the Italian OSM community after the earthquakes in Central Italy happened in late 2016.

Abstract

In Volunteered Geographic Information (VGI) projects, the tagging or annotation of objects is usually performed in a flexible and non-constrained manner. Contributors to a VGI project are normally free to choose whatever tags they feel are appropriate to annotate or describe a particular geographic object or place. In OpenStreetMap (OSM), the Map Features part of the OSM Wiki serves as the de-facto rulebook or ontology for the annotation of features in OSM. Within Map Features, suggestions and guidance on what combinations of tags to use for certain geographic objects are outlined. In this paper, we consider these suggestions and recommendations and analyse the OSM database for 40 cities around the world to ascertain if contributors to OSM in these urban areas are using this guidance in their tagging practices. Overall, we find that compliance with the suggestions and guidance in Map Features is generally average or poor. This leads us to conclude that contributors in these areas do not always tag features with the same level of annotation. Our paper also confirms anecdotal evidence that OSM Map Features is less influential in how OSM contributors tag objects. Document type: Article

Abstract

In Germany, the data of the Open Street Map project has become available as an alternative to proprietary road networks in commercial business geomatics software, and their customers are wondering whether the quality may be sufficient. This paper describes an implemented methodology to compare OSM street data with those of Navteq for all populated roads in Germany. As a unique feature, the presented methodology is based on a matching between the street objects of OSM and Navteq, and all steps are fully automated so that they can be applied to updated versions of both data sets. While there are considerable qualitative differences between regions, towns, and street categories, at a national level the relative completeness of objects, their relative precision and the relative completeness of names are high enough for maps. However, other attributes, which are needed for the computation of catchment areas, are still relatively incomplete.

Abstract

This paper describes the results of an analysis of the OpenStreetMap (OSM) database for the United Kingdom (UK) and Ireland (correct to April 2011). 15; 640 OSM ways (polygons and polylines), resulting in 316; 949 unique versions of these objects, were extracted and analysed from the OSM database for the UK and Ireland. In our analysis we only considered “heavily edited” objects in OSM: objects which have been edited 15 or more times. Our results show that there is no strong relationship between increasing numbers of contributors to a given object and the number of tags (metadata) assigned to it. 87% of contributions/edits to these objects are performed by 11% of the total 4128 contributors. In 79% of edits additional spatial data (nodes) are added to objects. The results in this paper do not attempt to evaluate the OSM data as good/poor quality but rather informs potential consumers of OSM data that the data itself is changing over time. In developing a better understanding of the characteristics of “heavily edited” objects there may be opportunities to use historical analysis in working towards quality indicators for OSM in the future. Document type: Article