FOSS4G 2022 academic track

The need to make electricity production increasingly sustainable requires careful planning of production plants, mainly for wind and photovoltaic energy conversion. Planning areas correctly, while respecting existing environmental constraints, is not an easy task and requires the collaboration of a panel of experts with different skills.

The need to search for new sites to be allocated to renewable energy generation plants is dictated by the most pressing current events, the search for non-impacting energy sources to whose research and development specific points of the National Resistance and Resilience Plan are dedicated, to which are added the consequences of the newborn Ukrainian conflict that has definitively discovered the problematic relationship-dependence of Italy and Europe with energy supplies from non-European countries. Both issues are pushing the country towards a rapid search for new energy strategies for environmental reasons and to make up for natural shortages that require massive imports of gas and other resources from abroad.
In particular, the National Recovery and Resilience Plan (PNRR), part of the European Next Generation EU (NGEU) programme, a 750 billion euro package allocated by the European Union to counteract the economic damage caused by the Covid-19 global pandemic, is an economic plan worth 248 billion euro that Italy can use in the five-year period from 2021 to 2026 to implement various reforms and repair the damage created by the pandemic crisis.
The plan, presented to the EU under the name 'Italia Domani', envisages investments along three main axes: digitalisation and innovation, ecological transition and social inclusion. These economic interventions are intended to resolve the drama caused by the advent of the Sars-Cov2 virus and help solve structural problems in the Italian economy, accompanying the country towards a path of ecological and environmental transition. It also aims to resolve important issues such as territorial, generational and gender gaps.
It is in this context that the national legislation is undergoing a revision, which has entrusted the regional administrations with the task of identifying the territorial criteria that favour or prevent the establishment of certain plants in the various areas of the territory. Each regional administration has the right to graduate the criteria according to the specific geomorphologic characteristics of its own territory and therefore the most efficient procedure would be to verify, with simulations in GIS environments, the effect of defining certain criteria on the territory to assess in advance which and how many areas could have greater or lesser suitability. On the basis of this consideration, we proceeded to experiment with the effects of the most common constraints by developing a real simulation on the territory of the Lazio Region.

The experimentation used the well-known open environment QGIS 3.22, which made it possible to exploit the possibilities offered by the open territorial databases of the Lazio Region.
It should be noted that the Lazio Region (like most Italian regions) has made many spatial data available in open format in recent years. The European directive called "Inspire" gave a boost to the use, standardisation and free dissemination of spatial data. It provides for the creation of a Community data infrastructure that simplifies the sharing between public administrations and user access to spatial information. In Italy, the directive was transposed into Italian law by Legislative Decree no. 32 of 27 January 2010, which established the National Infrastructure for Spatial Information and Environmental Monitoring as a node of the Community infrastructure. As a result of this implementation, the National Geoportal was created, which was followed by the various Regional Geoportals, such as that of the Lazio region.

The implementation of the open data in QGIS 3.12 made it possible to identify topological inaccuracies in the files provided and shared on the Lazio Region site, which led to necessary decisions such as the correction of some polygons that presented errors, such as their overlapping or imperfect closure (the correction of the latter case was suggested by QGis itself, through the "reopen geometries" function).
A possible inaccuracy was also found in the "lowland species" and "mountain species" files of the Regional Ecological Network, which seems to show an error in the transcription of the relative geodetic datum on the website, where it is reported as WGS84, UTM33N and resulting from verifications and overlapping more likely ED50 . Uncategorised areas also emerged in the file called "PTPR Regione Lazio (Tav. A - Tav. B)" which were however excluded from those considered to be unsuitable since a more detailed analysis revealed the area of the Parco della Caffarella in Rome, which is hardly conceivable as the site for a wind farm or large-scale photovoltaic plant. Extraterritorial areas within the Region's territory belonging to the State of "Vatican City" were also added as "unsuitable".
The first results show that the remaining areas after eliminating all those that are certainly unsuitable are a limited part of the Region itself. It should be noted that these areas are not definitely suitable areas but those that are not unsuitable or potentially suitable, even if further investigation is required to ascertain their suitability.
The limited extent of the areas remaining after the exclusion of the unsuitable areas suggested that we make an initial estimate of the sustainability of a total conversion to these energy sources for the whole region in order to assess its potential energy autonomy.
The analysis was extended to individual municipalities by comparing average yields per conceivable plant area, then comparing them with inhabitants for an initial estimate of energy needs at least for domestic use.

The survey took place in part of the so-called Roman Villa of Caposele, also known as Villa Rubino (Giuliani and Guaitoli 1972; Cassieri 2015). The Villa, built by the Dukes of Marzano and subsequently passed into the hands of Charles of Ligny, Prince of Caposele, was purchased by Ferdinand II of Bourbon in 1845, with the aim of making it a luxurious summer residence. The building overlooks the inlet of Caposele, where there must have been a small harbour, and is squeezed between the Via Appia and the sea. To the west of the small port are the remains of an imposing structure with a central courtyard, datable to the 1st century B.C., which scholarly tradition has identified as Cicero's Academy or School, although it is probably a horreum, testifying to the utilitarian vocation of this area of the villa. In later phases, while retaining its intended use, the horreum would be incorporated into a residential building complex together with other structures further to the west that, too, may have served as warehouses in the earlier phase. To the east of the marina is the residential area, the area in which the survey operations were concentrated. Here, on a front about 140 metres long, there are a series of rooms with barrel vaults that were probably part of the basis villae of the building. In two of these rooms are the so-called minor and major nymphaea. The first consists of an almost quadrangular room with a roof supported by four Doric brick columns; on the back wall, in a large niche, spring water gushes out. The wall decorations include stucco, shells and incrustations of glass paste and small stones. The main nymphaeum, on the other hand, is divided into three naves and covered with a rounded coffered vault supported by Doric columns. The large niche at the bottom of the nymphaeum contains a pool of spring water; the floor is in white mosaic with polychrome dots. These nymphaeums constitute the focus of the intervention.
In front of this front there was a very large fishpond, which ran into the sea for about one hundred metres in length, with a width of over 200.
Because of its architectural features and good state of preservation, the central body of the monument has always been a great attraction for visitors and scholars, many of whom have left descriptions and drawings in their diaries.

The two nymphaeums have to be surveyed both for conservation and study purposes and in order to allow a virtual visit, which is particularly important since they are located inside a private property. As already described, the structure is complex, with a succession of rooms and environments in an archaeological complex extending approximately 480 metres in an east-west direction and approximately 50 metres in a south-north direction. The survey of such an extension and such an articulation with consolidated techniques such as terrestrial laser scanning would probably have required days of work, and for this purpose we wanted to test the possible use of the most modern SLAM techniques, in particular using a GEOSLAM Zeb Horizon, totally transportable by an operator and with a range of up to 100 metres (https://geoslam.com/solutions/zeb-horizon/).
In order to compare the times, modes, precision and accuracy of the point cloud thus obtained, we took advantage of the possibilities provided by the open software "Cloud Compare 2.11.3 64 bit version", which allows us to compare point clouds of different origins. Cloud Compare allows comparisons to be made with various methods of calculating distance and to estimate precision and accuracy separately, allowing one cloud to be fitted to the other or to be compared while remaining within their absolute coordinates.
In the present experimentation it was therefore decided to survey both nymphaea with the "GEOSLAM", also surveying all the internal connecting rooms and corridors between these two environments. The whole survey was carried out in a few tens of minutes and therefore the survey continued over most of the exterior of the entire structure.
The survey of the entire complex was not carried out because the main interest of this project was to test the SLAM technology and validate its precision and accuracy in comparison with more consolidated techniques.
For comparison, only the major nymphaeum was surveyed with a more consolidated laser
Faro" terrestrial scanning laser.
In order to verify the validity of the Slam also on the external part, a survey was carried out using a DJI Matrix drone with laser scanning. Finally, the same survey was also carried out with an optical camera on the same Matrix drone and with the most widely used drone for photogrammetry, i.e. the "Phantom 4 pro", also by DJI.
All the surveys were framed with respect to the same network of ground control points, in order to refer them to the same framing system and be able to assess their precision and accuracy.
It should be noted that Slam was only able to station a few of the GCPs while, as can be easily guessed, the drones acquired practically all of them.

The comparison showed very limited deviations whose statistical validation is in progress, demonstrating that the SLAM technique can advantageously be used in such vast archaeological complexes where the completeness of the survey is more important than millimetric accuracy.