The solar radiation intercepted at a given location on the earth's surface is influenced by surface orientation and sky obstruction by surrounding topographic features. Viewshed models can be used to calculate sky obstruction for any given location on or above a complex topographic surface. We have developed an algorithm for rapid calculation of intercepted solar radiation using a combination o...

Given a terrain model, the viewshed from a viewpoint is computed as the set of X-Y positions of a point target such that the target is visible. We introduce a novel approach to the computation of accurate viewshed approximations. Our algorithm relies on the computation of an approximation to the so-called line-of-sight (LOS) function. This function is defined over target X-Y positions, and is t...

Preferences for developing 3600 MW offshore wind farms in Denmark are estimated based on data from a choice experiment. The variation willingness to pay the location of power development at 8, 12, 18, or 50 km shore is analysed as function gender, age, education, income, turbine viewshed, and beach visits. With space mixlogit model, we find that varies significantly income level, viewshed farms...

Viewshed analysis, often supported by Geographic Information Systems (GIS), is widely used in many application domains. However, as terrain data continue to become increasingly large and available at high resolutions, data-intensive viewshed analysis poses significant computational challenges. General-Purpose computation on Graphics Processing Units (GPGPU) provides a promising means to address...

The viewshed of a topographic dataset is the region around a given observation point that is visible from that location. Most GIS packages allow its computation. It has many uses, such as in urban environment planning, or in analysing archaeological site data. The viewshed is used here as a data enhancement tool to aid in the interpretation of geophysical potential field data. The fraction of t...

Many interesting application problems on terrains involve visibility computations; for example, the search for optimal locations of observation points, line-of-sight communication problems, and the computation of hidden or scenic paths. The solution of such problems needs techniques to answer visibility queries on a terrain eeciently, and/or the development of data structures encoding the visib...

Nowadays, there is a huge volume of data about terrains available and generally, these data do not fit in the internal memory. So, many GIS applications require efficient algorithms to manipulate the data externally. One of these applications is the viewshed computation that consists in obtain the visible points from a given point p. In this paper, we present an efficient algorithm to compute t...

The selection of the minimal number of observers that ensures the maximum visual coverage over an area represented by a digital elevation model (DEM) have great interest in many fields, e.g., telecommunications, environment planning, among others. However, this problem is complex and intractable when the number of points of the DEM is relatively high. This complexity is due to three issues: 1) ...

This paper examines the effects of database generalization on the area which is determined to be visible in GIs analysis. Many different methods of generalization are possible, but here, for any cell at the target resolution, elevations are determined from: the arithmetic mean, the maximum, the minimum, and the maximum difference from the mean of the cells within the kernel, and all possible co...