This paper describes a new parallel raster terrain visibility (or viewshed) algorithm, based on the sweep-line model of [Van Kreveld 1996]. Computing the terrain visible from a given observer is required for many GIS applications, with applications ranging from radio tower siting to aesthetics. Processing the newly available higher resolution terrain data requires faster architectures and algor...

This paper describes a means for linking Ž eld and object representations of geographical space. The approach is based on a series of mappings, where locations in a continuous Ž eld are mapped to discrete objects. An object in this context is a modeler’s conceptualization, as in a viewshed, highway corridor or biological reserve. An object can be represented as a point, line, polygon, network, ...

Quantifying the spatial extent, location and habitat associations of invasive tree species is critical to predict their future spread prioritise areas for management. Species–environment relationship analyses are useful tools understanding predicting potential geographical distribution these species; however, such require rigorous extensive data about presence and, crucially, area surveyed. Her...

 Nowadays, tourism is affected by the knowledge of a region’s climatic characteristics. Therefore, it is crucial to identify the potential regions and appropriate time for attracting tourists in relation to climatic comfort. Due to having climatic diversity and water resources such as rivers, waterfalls, caves and hot springs, Khorassan Razavi province is one of the potential regions for touris...

The County of Khorram-Abad enjoys a high potential for ecotourism because of its mountains, forests, natural mineral springs, natural waterfalls and diversity in folks and cultures. But, un-planned and uncontrolled ecotourism can have negative effects on environment, economy, culture and even the security of eco-tourists. The main purpose of this study is to present a fuzzy multi-criteria decis...

We describe statistical properties of the visual normal flow. These are used to model space-time texture, such as waterfalls, an open problem in visual motion analysis. The normal flow is perpendicular to edges. It is the only component of the image velocity that can be locally computed, so that it is simple to implement. We analysed the statistical representation of the normal flow magnitude f...