Use of the sensors of a latest generation mobile phone for the three-dimensional reconstruction of an archaeological monument: The survey of the Intihuatana stone in Machu Picchu (Peru')

The survey of archaeological monuments presents particular needs and difficulties. Such surveys must in fact be as complete, geometrically correct and accurately geo-referenced as possible. These needs, however, often face problems of difficult accessibility, the need for rapid timing and complex logistical conditions. The latest generation of mobile phones are equipped with ultra-high resolution cameras up to 100 megapixel. Although they do not have the geometric characteristics of professional cameras, they can be used advantageously for the reconstruction of three-dimensional models using Structure from Motion methodologies . At the same time, the latest mobile phones are equipped with GPS/GNSS chips that allow a postprocessing of their positioning allowing to reach decimetric/centimetric accuracies. The use of sensors integrated in a mobile phone greatly simplify the survey both in terms of transportability but also in terms of authorizations by the competent authorities as the equipment is exactly the same that most tourists who visit the sites themselves bring with them. The approach proposed and made possible by these combined features in a latest generation mobile phone have been tested for a rapid survey of the Intihuatana stone in Machu Picchu (Peru), a site with considerable logistical and organizing complexity

Use of the sensors of a latest generation mobile phone for the three-dimensional reconstruction of an archaeological monument: the survey of the Intihuatana stone in Machu Picchu (Peru’)

Abstract The survey of archaeological monuments presents particular needs and difficulties. Such surveys must in fact be as complete, geometrically correct and accurately geo-referenced as possible. These needs, however, often face problems of difficult accessibility, the need for rapid timing and complex logistical conditions. The latest generation of mobile phones are equipped with ultra-high resolution cameras up to 100 megapixel. Although they do not have the geometric characteristics of professional cameras, they can be used advantageously for the reconstruction of three-dimensional models using Structure from Motion methodologies . At the same time, the latest mobile phones are equipped with GPS/GNSS chips that allow a postprocessing of their positioning allowing to reach decimetric/centimetric accuracies. The use of sensors integrated in a mobile phone greatly simplify the survey both in terms of transportability but also in terms of authorizations by the competent authorities as the equipment is exactly the same that most tourists who visit the sites themselves bring with them. The approach proposed and made possible by these combined features in a latest generation mobile phone have been tested for a rapid survey of the Intihuatana stone in Machu Picchu (Peru), a site with considerable logistical and organizing complexity

A NEW BRANCH of the ANIO NOVUS AQUEDUCT (ROME, ITALY) REVEALED by ARCHAEOLOGY and GEOPHYSICS

The area south-east of Rome is characterised by the presence of several roman aqueducts which brought water to the eternal city from the Apennine and Alban Hills springs. In the last 40 years, several pieces of evidence about these aqueducts were acquired during the realisation of archaeological test trenches before building activities. In 2019, a small branch of a subterranean aqueduct unknown to the Latin sources was unearthed in Via dei Sette Metri. Here we show that this aqueduct is a lateral branch of the Anio Novus, a major imperial aqueduct built between 38 and 52 CE. To achieve this result, we employed detailed photogrammetric restitution of the new aqueduct and an integrated geophysical survey focused in the area where the Anio Novus was supposed to pass. Electrical Resistivity Tomography (ERT) and Ground Penetrating Radar (GPR) methods were used to reconstruct aqueduct paths and their relative heights. Different light conditions were tested during the picture acquisition step to determine the best practice in the photogrammetric restitution. The results obtained in this study confirmed the great effectiveness of the integration between geophysical investigation methods and the modern archaeology approach in detecting buried ancient structures

Solutions and limitations of the geomatic survey of an archaeological site in hard to access areas with a latest generation smartphone: the example of the Intihuatana stone in Machu Picchu (Peru)

Archaeological remains need to be geometrically surveyed and set in absolute reference systems in order to allow a "virtual visit" and to create "digital twins" useful in case of deterioration for proper restoration. Some countries (e.g., Peru) have a vast archaeological heritage whose survey requires optimized procedures that allow high productivity while maintaining high standards of geometric accuracy. A large part of Peru's cultural heritage is located in remote areas, at high altitudes and not easily accessible. For this reason, it is of great interest to study the possible applications of easily transportable instruments. In this study it was verified how the capabilities of the latest smartphones in terms of absolute differential positioning and photogrammetric acquisition can allow the acquisition of a geometrically correct and georeferenced three-dimensional model. The experimentation concerned a new survey of the Intihuatana stones at Machu Picchu and its comparison with a previous survey carried out with a much more complex laser scanning instrumentation. It is important to note that both the photogrammetric survey and the GPS/GNSS survey were carried out with the same smartphone taking full advantage of both features of the same mobile phone. Relative comparison to an existing point cloud provided differences of 2 millimeters in mean with an RMSE of 2 cm. The absolute positioning accuracy compared to a very large-scale cartography appears to be of the order of one metre as was expected mainly due to the high distance of the GPS/GNSS permanent stations

SIMULATION OF THE EFFECTS OF POSSIBLE REGULATIONS FOR THE LOCATION OF WIND AND PHOTOVOLTAIC POWER PLANTS IN THE LAZIO REGIONAL ADMINISTRATION (ITALY)

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 demanded by the most pressing current events: it’s just in such a context that the Italian national legislation is undergoing a revision, which has entrusted the regional administrations with the task of identifying the territorial criteria. By simulations in GIS environments, it’s possible to study the effect of defining certain criteria on the territory, in order to assess in advance which and how many areas could have greater or lesser suitability. Based on 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. The first results show that the remaining areas after eliminating all those that are certainly unsuitable are a limited part of the Region itself. 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

GNSS data for monitoring some movements on the island of Ischia

The aim of the present work is to present the first results of the study of integrated techniques for monitoring slow movements. In particular, the differential plano-altimetric accuracy characteristics of some sensors based on GPS/GNSS technology that use innovative proprietary algorithms are being tested; the high accuracy expected from these sensors requires a careful choice of comparison techniques, in particular SAR techniques are considered to be among the few comparable techniques. Currently, two of these sensors have already been installed at sites affected by slow movements, the nature of which is still being debated within the scientific community. These sites are in the territory of the municipality of Forio (Na) and close to the epicentre of the 2017 seismic event with epicentre in the municipality of Casamicciola. The movements under study (already observed by other researchers) are generally estimated to be in the order of a few centimetres per year therefore their monitoring and/or the possible establishment of an early warning system require millimetre or (possibly) sub-millimetre accuracies. Such accuracies are difficult (millimetric) or impossible (sub-millimetric) to obtain with 'classic' differential GPS/GNSS techniques, since the accuracies of these techniques are generally very close to the expected values of the movements under study. The study below will illustrate the first results on some time series of data obtained from receivers in classical post-processing mode that will be one of the benchmarks for the innovative technique

Mapping seismic vulnerability in buildings by means of open source tools and open data

In this paper we will show an example of the use of open source software and open data, recently available in Italy, for the determination of some parameters useful for assessing the seismic vulnerability of each building potentially exposed to such events. It should be noted that, at least in the national context, there have been a series of legal regulations that have made the properties of the buildings in the seismic zone, both of masonry and reinforced concrete, increasingly uniform. It is therefore important to evaluate the correlation between the implementation of these regulations with the actual damage suffered by such buildings during a real event. Among the various parameters that can then be hypothesized and used to estimate vulnerability, we will show a method to determine the year of construction of each single building, often not available with certainty at least on a nationwide scale. From this information, estimated for each single building in the center of the city of Aquila, the possible correlation will be evaluated with the actual damage recorded for the same buildings after the known magnitude 5.9 event of April 6, 2009 (Cheloni et al., 2010; Locati M. et al., 2011)

A new branch of the Anio novus aqueduct (Rome, Italy) revealed by archaeology and geophysics

The area south-east of Rome is characterised by the presence of several roman aqueducts which brought water to the eternal city from the Apennine and Alban Hills springs. In the last 40 years, several pieces of evidence about these aqueducts were acquired during the realisation of archaeological test trenches before building activities. In 2019, a small branch of a subterranean aqueduct unknown to the Latin sources was unearthed in Via dei Sette Metri. Here we show that this aqueduct is a lateral branch of the Anio Novus, a major imperial aqueduct built between 38 and 52 CE. To achieve this result, we employed detailed photogrammetric restitution of the new aqueduct and an integrated geophysical survey focused in the area where the Anio Novus was supposed to pass. Electrical Resistivity Tomography (ERT) and Ground Penetrating Radar (GPR) methods were used to reconstruct aqueduct paths and their relative heights. Different light conditions were tested during the picture acquisition step to determine the best practice in the photogrammetric restitution. The results obtained in this study confirmed the great effectiveness of the integration between geophysical investigation methods and the modern archaeology approach in detecting buried ancient structures