Green spaces and natural environments are essential for quality of life, as they influence health behaviours and outcomes positively. The quantification of “greenness” observable from the human perspective is of great interest, especially in urban environments where built-up areas and infill are expanding. In this paper, we present a method based on airborne laser scanning (ALS) point clouds that makes it possible to simulate a space observed from the human perspective and to quantify the surrounding vegetation. The method can be applied over various spatial scales, in urban, suburban and rural regions. We employed this new method to analyse a set of specific locations in Switzerland that are important for people to recover from everyday stress. The greenness quantification can be used to compare the perceived restorative quality of landscape characteristics with physical landscape qualities. Our approach provides a viable methodological solution for spatial planning and large-scale socio-ecological studies on the influence of natural and green spaces on health and wellbeing, and we recommend that it be applied in the natural landscape and in urban areas.