Viewshed Analysis and Visualization of Landscape Voxel Models

In this study, we carry out viewshed analysis to landscape voxel models derived from airborne laser scanner data. The objective is to make comparisons of viewshed analysis with different voxel models; the ground model representing the bare Earth, the surface model including also all above-ground features, and the combined model, which is formed from the ground model and the laser measurements in voxel domain. The combined model contains openings in vegetation below tree crowns. This paper explores the variation in the size of the visible area when the different voxel models are used. The generated voxel models and results from viewshed analysis are visualized using a number of cartographic means. The methods include generation of voxel model, implementation of the Line of Sight (LoS) algorithm and visualization techniques. The airborne laser data is classified to ground and other points before creation of a voxel model. Results of the study present the influence of using a real 3D model instead of 2.5D surface in the calculation of viewshed analysis. The produced visualizations are compared, and positive and negative aspects of the representations are analysed.