Exploring multiple viewshed analysis using terrain features and optimisation techniques

The calculation of viewsheds is a routine operation in geographic information systems and is used in a wide range of applications. Many of these involve the siting of features, such as radio masts, which are part of a network and yet the selection of sites is normally done separately for each feature. The selection of a series of locations which collectively maximise the visual coverage of an area is a combinatorial problem and as such cannot be directly solved except for trivial cases. In this paper, two strategies for tackling this problem are explored. The first is to restrict the search to key topographic points in the landscape such as peaks, pits and passes. The second is to use heuristics which have been applied to other maximal coverage spatial problems such as location-allocation. The results show that the use of these two strategies results in a reduction of the computing time necessary by two orders of magnitude, but at the cost of a loss of 10% in the area viewed. Three different heuristics were used, of which Simulated Annealing produced the best results. However the improvement over a much simpler fast-descent swap heuristic was very slight, but at the cost of greatly increased running times. © 2004 Elsevier Ltd. All rights reserved

Visibility graphs and landscape visibility analysis

Visibility analysis based on viewsheds is one of the most frequently used GIS analysis tools. In this paper we present an approach to visibility analysis based on the visibility graph. A visibility graph records the pattern of mutual visibility relations in a landscape, and provides a convenient way of storing and further analysing the results of multiple viewshed analyses for a particular landscape region. We describe how a visibility graph may be calculated for a landscape. We then give examples, which include the interactive exploration ofa landscape, and the calculation of new measures of a landscape?s visual properties based on graph metrics ? in particular, neighbourhood clustering coefficient and path length analysis. These analyses suggest that measures derived from the visibility graph may be of particular relevance to the growing interest in quantifying the perceptual characteristics of landscapes

A Prototype Path Prediction Tool

When a person moves through an environment he/she will decide where to travel based on their interpretation of the surroundings. This becomes important in search and rescue scenarios and military operations when a person’s route is of interest. One solution to predict this route is to model the way people travel. This paper documents the process of developing a prototype path prediction tool using the Python scripting language and ArcMap tools. The general model approach was to create a simulation based on a least cost path analysis restricted by viewshed analysis. While the concept is straightforward, creating the program proved complex due to the management of vector and raster data, and accounting for numerous application possibilities and variable combinations. The result was a durable simulation capable of incorporating a directional bias, observer height, travel speed, and the ability to accommodate a level of randomness

Calculating the inherent visual structure of a landscape (inherent viewshed) using high-throughput computing

This paper describes a method of calculating the inherent visibility at all locations in a landscape (‘total viewshed’) by making use of redundant computer cycles. This approach uses a simplified viewshed program that is suitable for use within a distributed environment, in this case managed by the Condor system. Distributing the calculation in this way reduced the calculation time of our example from an estimated 34 days to slightly over 25 hours using a cluster of 43 workstations. Finally, we discuss the example ‘total viewshed’ raster for the Avebury region, and briefly highlight some of its implications

From isovists to visibility graphs: a methodology for the analysis of architectural space

An isovist, or viewshed, is the area in a spatial environment directly visible from a location within the space. Here we show how a set of isovists can be used to generate a graph of mutual visibility between locations. We demonstrate that this graph can also be constructed without reference to isovists and that we are in fact invoking the more general concept of a visibility graph. Using the visibility graph, we can extend both isovist and current graph-based analyses of architectural space to form a new methodology for the investigation of configurational relationships. The measurement of local and global characteristics of the graph, for each vertex or for the system as a whole, is of interest from an architectural perspective, allowing us to describe a configuration with reference to accessibility and visibility, to compare from location to location within a system, and to compare systems with different geometries. Finally we show that visibility graph properties may be closely related to manifestations of spatial perception, such as way-finding, movement, and space use

Calculating the inherent visual structure of a landscape ('total viewshed') using high-throughput computing

This paper describes a method of calculating the inherent visibility at all locations in a landscape (‘total viewshed’) by making use of redundant computer cycles. This approach uses a simplified viewshed program that is suitable for use within a distributed environment, in this case managed by the Condor system. Distributing the calculation in this way reduced the calculation time of our example from an estimated 34 days to slightly over 25 hours using a cluster of 43 workstations. Finally, we discuss the example ‘total viewshed’ raster for the Avebury region, and briefly highlight some of its implications

A call for viewshed ecology : Advancing our understanding of the ecology of information through viewshed analysis

JA was supported by funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 661211, and JMJT by NERC grant NE/J008001/1.Peer reviewedPostprin

Greenway Trail Viewshed Characteristics: Planning Applications Using GIS and Remote Sensing

This study applies theoretical findings relating greenway trail viewshed characteristics to a proposed greenway trail. Utilizing geographic information systems and remote sensing techniques, this study compares the viewshed characteristics of two proposed routes to connect an existent greenway trail system to Wilson’s Creek National Battlefield in Greene County, MO. Light Detection and Ranging data is then used to map the viewshed of each route and calculate the openness and interconnectedness of each viewshed. High-resolution multispectral imagery is then used to calculate the Normalized Difference Vegetation Index measuring the “greenness” within each viewshed. Finally, parcel-level land use data is used to calculate the diversity of land use within each viewshed. The values from these measurements are then compared between the two routes to determine the potential for each in promoting increased trail use. The study sheds light on the uncertainties and limitations of applying these geospatial techniques to not-yet-existent trails, but the outcomes are promising. Even without further research, this study shows that objective viewshed criteria can be gathered to help inform greenway planning and development. This research aids planners by demonstrating methods for evaluating potential greenway trail construction sites remotely. This research also provides researchers with an applied case study adding to the existing body of literature