Lukas Loos

The emergence and evolution of OpenStreetMap: a cellular automata approach

Collaborative mapping projects, such as OpenStreetMap (OSM), have received tremendous amounts of contributed data from voluntary participants over time. So far, most research efforts deal with data quality issues, but the OSM evolution across space and over time has not been noted. Therefore, this study is dedicated to the evolution of the contributed information in order to understand an emergent phenomenon of so-called collaborative contributing. The main objective of this paper is to monitor the evolutional pattern of OSM and predict potential future states through a cellular automata (CA) model. This is exceedingly relevant for numerous OSM-based applications. Descriptive spatiotemporal analysis of the contributions for the time period 2007–2012, using the city of Heidelberg (Germany) as a case study, reveals that early contributions are given three years after the launching of OSM, while after nearly six years, most of the areas are discovered. The simulation results for the validated CA model, predicting OSM states for 2014, provide clear evidence that most of the areas have been explored three years after people began mapping until 2010, and thereafter, the densification process has begun and will cover most parts of the city although the amount of contribution depends on the land use types.

Show Me the Data!: Structuring Archaeological Data to Deliver Interactive, Transparent 3D Reconstructions in a 3D WebGIS

Creating 3D reconstructions is a common approach today in archaeology and cultural heritage. The problem is that 3D models in online virtual research environments may tempt users to believe them as historical truth. What must be done to enable the public to view a 3D reconstruction as a hypothesis and have access to the supporting data? This paper explains – via use-case examples from the ancient Maya city of Copan, Honduras – a procedure for structuring heterogeneous data to enable interactive, web-based access to 3D reconstructions of cultural heritage. A prototype 3D WebGIS system was built that can store, manage, and visualize 3D models and integrates these with georeferenced archaeological data. An ontology was created, a segmentation pipeline was developed, and databases and services were designed to structure and integrate the data in the 3D WebGIS. Results include two interactive 3D reconstructions: a city model and a temple model – these demonstrate how proper data structuring can deliver transparent models for archaeological argumentation.