Metropogis: a city modeling system

Peer Reviewe

Metropogis: a city modeling system

Peer Reviewe

"Der Balkan" in der Krone: Austria between "frontier Orientalism" and amnesiac nationalism

This article traces the “silent inscription” of (former) colonial relations in the European integration project to their re-inflection in an EU-sceptical medium. To do so, this contribution draws on a corpus of data comprising news-coverage, commentaries and readers’ letters published in Austria’s largest newspaper, the Kronen Zeitung, whose reach, influence and leanings are well-known. The analysis considers the Krone’s representations of, and discursive references to, “the Balkans” during the crises-littered period between 2009 and 2017. For analytical purposes this discussion focuses on a sub-sample of invocations of “the Balkans” in the Krone, which have appeared with growing frequency since 2015. Conceptually, the discourse-analytical notion of the topos, or argumentative structure, and anthropological literature on “identity grammars” inform the analysis. The discussion reveals continuities with Austria’s historically long-established representational regimes of South-Eastern Europe, and novel discursive features. A contemporary paternalism is shown to re-appropriate the nineteenth-century topos of Austria’s alleged “civilizing mission” and what André Gingrich (2005) has described as Central Europe’s “frontier Orientalism”. Further, preoccupations with “the Balkan-route” and its closure articulate a topos of external threats tied to recent migration flows. The article reflects on an “amnesiac nationalism”, and its post-imperial entanglements, that are currently re-shaping the European Union

2004: MetropoGIS: A city modeling system

The contribution of this paper is threefold. First, we will report on a system that automatically generates a 3D block model from digital aerial images. In this part we will focus on the automatic aerial triangulation and a dense matching process. The second part addresses the augmentation of this 3D block model of a real city with geo-referenced terrestrial data of the facades. The terrestrial images are acquired by a hand-held digital consumer camera. The relative orientation of the photographs is calculated automatically and fitted towards the 3D block model with minimized human input using vanishing points. The extraction of 3D primitives on the facades is based on area based matching and line matching over multiple oriented images. Third, we report on high quality reconstructions of selected objects like historic and otherwise important building facades and statues. The proposed city modeling system delivers a fully 3D geographic information data set of a city in different levels of detail and is called MetropoGIS.

Using images to estimate reflectance functions

A new method for the evaluation of the bidirectional reflectance distribution function (BRDF) is presented. The proposed procedure foregoes the usage of special equipment like pohotogoniometers or imaging reflectometers but rather uses of-the-shelf hardware like CCD cameras. The BRDF is determined from the image data, thus capturing several incident angles at each measurement. Using a diffuse reflectance standard the effects of ambient and stray light can be reduced. The presented method offers an easy and cost efficient way to measure material properties needed for physically based rendering algorithms

Fast Event-Driven Refinement of Dynamic Levels of Detail

Dynamic levels of detail allow fine grained selection of actually rendered geometry suitable for the current viewing parameters. Therefore, the visual quality of interactive 3D applications is usually higher than the quality achieved by traditional static level of detail approaches. On the other hand, this fine grained representation requires more CPU time for runtime refinement of the displayed mesh. We report on an event-driven refinement method that decreases the selection time significantly. Our approach exploits coherence between successive frames explicitly to reduce the number of tests necessary for node refinements. For large virtual environments we observed, that our method performs best when the actually displayed mesh is very complex. In these cases our approach is several times faster than the primal methods for dynamic level of detail refinement

Progressive compression of visibility data for view-dependent multiresolution meshes

In this paper we present a lossless and optionally lossy compression method for precomputed visibility data for view-dependent multiresolution meshes, which supports out-of-core rendering and progressive transmission through slow connections. Our approach has the feature, that visibility information can be stored directly in the nodes of the multiresolution structure and only necessary parts of visibility data need to be transmitted. Nevertheless our lossless compression method performs better than wellknown general purpose solid compressors which inhibit selective access of required data. Even higher compression can be achieved when lossy preprocessing is performed. We evaluate our method on several arti cial and real datasets