Elsevier, Fuzzy Sets and Systems, 1(135), p. 63-80, 2003
DOI: 10.1016/s0165-0114(02)00250-6
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The construction of inter-visibility models for a terrain. is an important tool for environmental and animal studies. Efficient crisp algorithms are known to address this problem directly on a raster digital elevation map (DEM) of the study area. Randomness plays an important role: several factors like vegetation, height of the observer, presence of unmapped human artifacts, etc. cannot be modeled in advance into a traditional DEM model. We propose the use of fuzzy terrain models to incorporate uncertainty and unpredictable variability of the landscape. Accordingly, we propose a suitable definition of visibility to obtain inter-visibility models. An algorithm that uses approximation of fuzzy numbers with a discrete family of intervals is proposed. The proposed model produces sound results and can be extended to model complex situations like triangulating a radio source using two directional receivers. All of these situations are difficult to manage with a precise stochastic model and are a frequent occurrence in animal behavior studies under field conditions. The proposed techniques have been implemented inside a user-friendly software package that may easily exchange data with the most common GISs. We report also some experimental results obtained using over artificial terrain under controlled noise and under-sampling conditions. (C) 2002 Elsevier Science B.V. All rights reserved.