Geothematic open data in Umbria region.

Detailed information about geology, hydrogeology and seismic hazard issues for Umbria region are contained in a spatial database available as open data format (shapefile or KMZ) and distributed under the regional open data portal called Open Data Umbria ( http://dati.umbria.it ) where 297 datasets have been produced by Umbria Region until now and most of them are made by Geological Survey. Geological Survey of Regione Umbria carried out a 20 years program to produce 276 geological maps at 1:10.000 reference scale with an accurate geological model of the regional surface and providing millions of geological data. The key word is the characteristic index of the single geologic unit. Characteristic index, shown in percentage, calculates the ratio between the surface of the geologic units compared to their thickness. Thickness value for each geologic unit is intended to be based on rank level and calculated as weighted average of the thickness for each geologic unit. Standardization of geological data and data availability Detailed information about geology, hydrogeology and seismic hazard issues for Umbria region are contained in a Geological DataBase (GDB from now on), a spatial database available as open data format (shapefile or KMZ format) and distributed under the regional open data portal called Open Data Umbria (http://dati.umbria.it/dataset/cartageologica-dell-umbria) where 297 datasets have been produced by Geological Survey of Regione Umbria until now and most of them are made by Geological Survey. Development of standardized regional geologic database took about 2 years since 2010 to manage the huge set of information contained in the 276 former geologic maps, covering the whole territory of Umbria.As a result of migration to GDB, 231 distinct geologic units were found for Umbria Region territory represented by about 47,000 polygon features. The total land area of Umbria 8,475 km 2 wide is divided in the GDB into 46,982 different geological areas. Analysis of the information contained in the GDB is preliminary to the creation of more geothematic layers and custom maps led us to define an item describing in a comprehensive way the geological units: the geological representativeness and the Characteristic Index of the single geologic unit. This means evaluating geological units or domains not just for their 2D extent but even in 3 dimensions. Characteristic index, shown in percentage, calculates indeed the ratio between the surface of the geologic units and their thickness. Thickness value for each geologic unit is intended to be based on rank level and calculated as weighted average of the thickness for each geologic unit. Examples are shown in figure 1 and 2, the areas occupied by the alluvial deposits and terraced and those of ancient and very ancient alluvial deposits of Pliocene-Pleistocene age. Figure 1, shows the area occupied by the current and terraced alluvial deposits and those of ancient alluvial deposits of Pliocene-Pleistocene age. In light blue areas occupied by the alluvial deposits and current terraces, which occupy 17.3% of the region, and in yellow the ancient and very ancient alluvial deposits, which occupy 19% of the region. Globally, therefore, the alluvial deposits of different ages occupy 36.3% of the region, far out 1/3 of the entire region. The geological representativeness of current and terraced alluvial deposits is 0.56%, while that of the very old and ancient alluvial deposits is 26%. No doubt These numbers indicate that the alluvial deposits current have a geologic representativeness very different from the more ancient, the former deposits extent is large but its thickness is PeerJ Preprints | https://doi.org/10.7287/peerj.preprints.2096v2 | CC BY 4.0 Open Access | rec: 9 Aug 2016, publ: 9 Aug 2016 pellicular with an approximately 1/45 of the form factor; on the other hand the latter show a little thickness compared to their extent. Figure 2 shows at regional level the situation for merged and reclassified geological units compared to the percentage of total land area, and Figure 3 the geological representativeness of the geological domains for the