Abstract

This paper presents a methodology for urban monitoring using volunteered geographic information (VGI) and journalism data Iraq war logs with network based kernel density estimation (NetKDE). It investigates, using spatio-temporal analysis, the evolution of urban events in Baghdad between 2004 and 2009. The extracted street network is based on the data distributed by OpenStreetMap (OSM). A total of 21,876 logged events, 66,648 network segments, 22,644 gridpoints (200m resolution grid) and 362,304 gridpoints (50m resolution grid) are used for the analysis. The methodology combines and adapts these VGI data and is mainly based on open source and/or publicly available software. It handles very large datasets with multiscale, multi-resolution and temporal perspectives. Fuzzy-set map comparison (FMC) is used to identify level of changes between each period of time. The methodology is already used in other fields of research being biology, urban planning, criminology or economic evelopment. It should help stakeholders in respective domain to analyze the evolution of network constrained events in multiple contexts. This paper is divided in three parts. Firstly, conceptual background of VGI, NetKDE and FMC is presented. Secondly, the methodology is illustrated using data Iraq war logs, OSM data and grids with two different resolutions. Thirdly, spatio-temporal analysis results are presented and discussed. Peer Reviewed

Abstract

Due to financial or administrative constraints, access to official spatial base data is currently limited to a small subset of all potential users in the field of spatial planning and research. This increases the usefulness of Volunteered Geographic Information (VGI), in particular OpenStreetMap (OSM), as supplementary datasets or, in some cases, alternative sources of primary data. In contrast to the OSM street network, which has already been thoroughly investigated and found to be practically complete in many areas, the degree of completeness of OSM data on buildings is still unclear. In this paper we describe methods to analyze building completeness and apply these to various test areas in Germany. Official data from national mapping and cadastral agencies is used as a basis for comparison. The results show that unit-based completeness measurements (e.g., total number or area of buildings) are highly sensitive to disparities in modeling between official data and VGI. Therefore, we recommend object-based methods to study the completeness of OSM building footprint data. An analysis from November 2011 in Germany indicated a completeness of 25% in the federal states of North Rhine-Westphalia and 15% in Saxony. Although further analyses from 2012 confirm that data completeness in Saxony has risen to 23%, the rate of new data input was slowing in the year 2012. Document type: Article