The best known output-sensitive sequential algorithm for computing the viewshed on a polyhedral terrain from a given viewpoint was proposed by Katz, Overmars, and Sharir 10 , and achieves time complexity O((k + nn(n)) log n) where n and k are the input and output sizes respectively, and () is the inverse Ackermann's function. In this paper, we present a parallel algorithm that is based on the w...

This paper demonstrates a toolkit for multiple observer siting to maximize their joint viewshed, on high-resolution gridded terrains, up to 2402 × 2402, with the viewsheds’ radii of up to 1000. It shows that approximate (rather than exact) visibility indexes of observers are sufficient for siting multiple observers. It also shows that, when selecting potential observers, geographic dispersion i...

We present an approach to determine the credibility of content provided within a visual VGI source such as Flickr. We propose analysing the variability of selected user and photo metadata of geotagged Flickr photos with the location correctness of these images, which is our reference quality measure. These observed user and photo metadata can help to infer the credibility of contributors.

The Battle of Midway (June 4 – 6, 1942) is considered one of the pivotal naval encounters of the Second World War. The battle has been examined in detail within both popular and scholarly literature, and a common opinion found in virtually all of these examinations is that Japanese search efforts on the morning of June 4, which were intended to determine if any U.S. naval forces were present, w...

Many of today’s scenic assessment tools were developed initially to preserve the visual quality public lands and mitigate negative impacts large-scale landscape alterations, such as timber harvesting, mineral extraction, renewable energy production. However, we are beginning see more interest today in preserving views on non-public lands. This essay makes a case for additional that reveal deep ...

This article describes a new model for urban planning in ancient and preindustrial cities that moves beyond the traditional simplistic dichotomy of planned versus organic cities. The model has two components: coordination of buildings and spaces, and standardization among cities. A variety of coordinated arrangements of buildings reflect urban planning, including simple coordination, formality ...

We present a novel exploratory method combining line of sight visibility (viewshed analysis) and techniques from social network analysis to investigate archaeological data. At increasing distances different nodes are connected creating a set of networks, which are subsequently described using centrality measures and clustering coefficients. Networks with significant properties are examined in m...