r.survey: a tool for calculating visibility of variable-size objects based on orientation

Identification of terrain surface features can be done using approaches such as visual observation or remote sensing image processing. Accurate detection survey targets at the ground level primarily depends on human acuity sensor resolution, and then acquisition geometry (i.e. relative position orientation between surveyor terrain). Further, delimitation observer’s viewshed boundary sensor’s footprint is sometimes insufficient to ensure that all enclosed correctly detected. Size hamper target visibility. In this paper we describe a new release r.survey, an open-source spatial analysis tool for assessment. This offers necessary information assess how morphology perceived by observers and/or sensors means three basic visibility metrics: 3D distance, view angle, solid angle. It also fully customizable, allowing single multiple points, aerial point view, size setting observed target, making it useful many different purposes.