Quality assessment of a landslide inventory map and its application to landâuse planning. A case study in the Northern Apennines (EmiliaâRomagna region, Italy)
Landslide hazard and risk are growing as a consequence of climate change and demographic pressure. Landâuse planning represents a powerful tool to manage this socioâeconomic problem and build sustainable and landslide resilient communities. Landslide inventory maps are a cornerstone of landâuse planning and, consequently, their quality assessment represents a burning issue.
This work aimed to define the quality parameters of a landslide inventory and assess its spatial and temporal accuracy with regard to its possible applications to landâuse planning. In this sense, I proceeded according to a twoâsteps approach. An overall assessment of the accuracy of data geographic positioning was performed on four case study sites located in the Italian Northern Apennines. The quantification of the overall spatial and temporal accuracy, instead, focused on the Dorgola Valley (Province of Reggio Emilia). The assessment of spatial accuracy involved a comparison between remotely sensed and field survey data, as well as an innovative fuzzylike analysis of a multiâtemporal landslide inventory map. Conversely, longâ and shortâterm landslide temporal persistence was appraised over a period of 60 years with the aid of 18 remotely sensed image sets. These results were eventually compared with the current Territorial Plan for Provincial Coordination (PTCP) of the Province of Reggio Emilia.
The outcome of this work suggested that geomorphologically detected and mapped landslides are a significant approximation of a more complex reality. In order to convey to the endâusers this intrinsic uncertainty, a new form of cartographic representation is needed. In this sense, a fuzzy raster landslide map may be an option. With regard to landâuse planning, landslide inventory maps, if appropriately updated, confirmed to be essential decisionâsupport tools. This research, however, proved that their spatial and temporal uncertainty discourages any direct use as zoning maps, especially when zoning itself is associated to statutory or advisory regulations.