Mapping ecosystem services (ES) increases the awareness of natural capital value, leading to building sustainability into decision-making processes. Recently, many techniques to assess the value of ES delivered by different scenarios of land use/land cover (LULC) are available, thus becoming important practices in mapping to support the land use planning process. The spatial analysis of the biophysical ES distribution allows a better comprehension of the environmental and social implications of planning, especially when ES concerns the management of risk (e.g., erosion, pollution). This paper investigates the nutrient retention model of InVEST software through its spatial distribution and its quantitative value. The model was analyzed by testing its response to changes in input parameters: (1) the digital terrain elevation model (DEM); and (2) different LULC attribute configurations. The paper increases the level of attention to specific ES models that use water runoff as a proxy of nutrient delivery. It shows that the spatial distribution of biophysical values is highly influenced by many factors, among which the characteristics of the DEM and its interaction with LULC are included. The results seem to confirm that the biophysical value of ES is still affected by a high degree of uncertainty and encourage an expert field campaign as the only solution to use ES mapping for a regulative land use framework.

In this paper a method for the estimation of the visual impact of buildings with symbolic relevance, such as skyscrapers that are out of scale with their surrounding urban space, is discussed and applied. It is based on the viewshed analysis as developed in rural landscape studies, but it also takes into account the peculiarity emerging from the urban studies. In order to go beyond the sole information of whether a cell is, or is not, visible, which is typical of viewshed analyses, in this work the various factors that cause the visual attenuation with the distance are discussed and quantitatively assessed by determining various limit-of-visibility distances that may also be time variable. These factors are the visual acuity, the contrast between the target and its surroundings, the atmospheric visibility, and the recognition process of the subject. An application of this methodology is carried out on various case study buildings in the city of Turin, Italy (an ancient building, an urban landmark, the Mole, and a skyscraper under construction). From the visibility maps, under various conditions, it can be seen that the new skyscraper will be a major landmark not only for the entire city, but also for the surrounding municipalities.