Alexandra RÁŠOVÁ

Vegetation modelling in 2.5D visibility analysis

Rášová, A.: Vegetation modelling in 2.5D visibility analysis. Kartografické listy, 2018, 26 (1).

Abstract: The effect of vegetation, so-called ‘tree factor’, is an issue that is often overlooked or not considered in visibility analysis. Partially, this is due to the lack of data that would express its changing characteristics, such as height, spatial extent or other properties. In this paper, we explore the possibilities of including the vegetation in the visibility analyses that relies on 2.5D digital elevation models. We discuss the modelling of stand-alone trees placed in a short distance from the viewing point, where they do not necessarily block the entire view. In the long-distance scenario, we explore the modelling techniques of opaque vegetation with known and unknown spatial extent and height. The probable viewshed proved to be a useful tool to estimate the uncertainty of the viewshed derived from global digital elevation models, which are affected by the vegetation present in these models. The proposed techniques are based on the common 2.5D modelling, so they are easy to integrate with other analytical layers.

Keywords: viewshed, visibility, vegetation, probable viewshed, spatial analysis, visual perme-ability, GIS, TanDEM-X, SRTM, ALOS PALSAR