Monitoring post-fire forest recovery using multi-temporal Digital Surface Models generated from different platforms

Wildfires can greatly affect forest dynamics. Given the alteration of fire regimes foreseen globally due to climate and land use changes, greater attention should be devoted to prevention and restoration activities. Concerning in particular post-fire restoration actions, it is fundamental, together with a better understanding of ecological processes resulting from the disturbance, to define techniques and protocols for long-term monitoring of burned areas. This paper presents the results of a study conducted within an area affected by a stand-replacing crown fire (Verrayes, Aosta (AO), Italy) in 2005, which is part of a long-term monitoring research on post-fire restoration dynamics. We performed a change detection analysis through a time sequence (2008-2015) of DSMs (Digital Surface Models) obtained from LiDAR (ALS - Airborne Laser Scanner) and digital images (UAV - Unmanned Aerial Vehicle flight) to test the ability of the systems (platform + sensor) to identify the ongoing processes. New technologies providing high-resolution information and new devices (i.e. UAV) able to acquire geographic data “on demand” demonstrated great potential for monitoring post disturbance recovery dynamics of vegetation

Residual entropy and critical behavior of two interacting boson species in a double well

Motivated by the importance of entanglement and correlation indicators in the analysis of quantum systems, we study the equilibrium and the bipartite residual entropy in a two-species Bose Hubbard dimer when the spatial phase separation of the two species takes place. We consider both the zero and non-zero-temperature regime. We present different kinds of residual entropies (each one associated to a different way of partitioning the system), and we show that they strictly depend on the specific quantum phase characterizing the two species (supermixed, mixed or demixed) even at finite temperature. To provide a deeper physical insight into the zero-temperature scenario, we apply the fully-analytical variational approach based on su(2) coherent states and provide a considerably good approximation of the entanglement entropy. Finally, we show that the effectiveness of bipartite residual entropy as a critical indicator at non-zero temperature is unchanged when considering a restricted combination of energy eigenstates.Comment: 18 pages, 9 figure

Archaeological site monitoring: UAV photogrammetry can be an answer

During archaeological excavations it is important to monitor the new excavated areas and findings day by day in order to be able to plan future excavation activities. At present, this daily activity is usually performed by using total stations, which survey the changes of the archaeological site: the surveyors are asked to produce day by day draft plans and sections which allow archaeologists to plan their future activities. The survey is realized during the excavations or just at the end of every working day and drawings have to be produced as soon as possible in order to allow the comprehension of the work done and to plan the activities for the following day. By using this technique, all the measurements, even those not necessary for the day after, have to be acquired in order to avoid a ‘loss of memory'. A possible alternative to this traditional approach is aerial photogrammetry, if the images can be acquired quickly and at a taken distance able to guarantee the necessary accuracy of a few centimeters. Today the use of UAVs (Unmanned Aerial Vehicles) can be considered a proven technology able to acquire images at distances ranging from 4 m up to 20 m: and therefore as a possible monitoring system to provide the necessary information to the archaeologists day by day. The control network, usually present at each archaeological site, can give the stable control points useful for orienting a photogrammetric block acquired by using an UAV equipped with a calibrated digital camera and a navigation control system able to drive the aircraft following a pre-planned flight scheme. Modern digital photogrammetric software can solve for the block orientation and generate a DSM automatically, allowing rapid orthophoto generation and the possibility of producing sections and plans. The present paper describes a low cost UAV system realized by the research group of the Politecnico di Torino and tested on a Roman villa archaeological site located in Aquileia (Italy), a well-known UNESCO WHL site. The results of automatic orientation and orthophoto production are described in terms of their accuracy and the completeness of information guaranteed for archaeological site excavation managemen

Planned maintenance for architectural heritage. Experiences in progress from 3D survey to intervention programmes through HBIM

The continuous evolution of 3D surveying and modelling techniques, using increasingly high-performance tools and applications, highlights the added value of these methods in the field of urban and architectural survey. In the case study presented, attention is focused particularly on applications useful for the planned maintenance of cultural heritage (CH). These tools and methods have a significant impact on the phase of interpretation and "physical" knowledge. They can also bring a critical contribution to the completion of models that are not only geometric but also semantic and informative, supporting 360-degree planning of the maintenance of our historical architectural heritage. This support for scheduled maintenance has been identified in the HBIM methodology, based on an integrated 3D metric survey. A three-year research project on this topic (Interreg Italy-Switzerland "MAIN.10.ANCE", 2019-2022), partnered by Politecnico di Torino, is currently in the start-up phase. The main focus of the project is a UNESCO heritage site: the "Sacri Monti" (Sacred Mountains) of Italy and those in Canton of Ticino (Switzerland), with the need for a common and shared conservation plan

Un nuovo approccio per la gestione delle risorse idriche sotterranee in ambito transfrontaliero: Prog. ALCOTRA-ALIRHYS

In seguito ai mutamenti climatici degli ultimi anni sono aumentati i rischi legati alle risorse idriche sotterranee, relativamente alle quali, una buona conoscenza finalizzata alla loro gestione e ottimizzazione è l'obiettivo del progetto, realizzato nel territorio tra Cuneo e Nizza a partire da marzo 2013. Il progetto prevede numerose acquisizioni sul campo di dati legati alle fonti di approvvigionamento delle risorse idriche mediante il monitoraggio di parametri chimici, fisici e isotopici di oltre 20 sorgenti, particolarmente significative, da correlare con i valori di precipitazione registrati da stazioni meteo e da nivo-pluviografi interrati appositamente installati. I dati vengono raccolti e gestiti in un Sistema Informativo Territoriale, adeguatamente progettato e strutturato secondo le regole dei database, per consentirne l'indipendenza dal software (commerciale o freeware), la corretta comprensione e procedure semplici di aggiornamento/modifica futuri. I dati di diversa natura raccolti dalle unità coinvolte vengono archiviati in un unico ambiente condiviso per una efficace connessione territoriale che consenta una corretta analisi dinamica delle informazioni contenute. Il SIT raccoglie la cartografia di base e i modelli altimetrici, a diverse scale e formati, dei territori dei due Stati in modo da integrare i differenti sistemi di riferimento planimetrici e altimetrici e i diversi tipi di proiezione cartografica, secondo le indicazioni INSPIRE. Il SIT prodotto è utilizzabile per l'aggiornamento continuo e per la diffusione dei risultati secondo tre livelli: traduzione in WebGIS, tramite la piattaforma open-source Geonode, per la condivisione delle informazioni e della cartografia automatica elaborabile, consentendo l'interazione da parte di utenti esterni; condivisione remota di dati vettoriali tramite Web Feature Service o Web Coverage Service; produzione dinamica di mappe tramite Web Map Service. La diffusione dei risultati di ALIRHYS viene conseguita mediante un sito internet che raccoglie, descrive e mette a disposizione dati e risultati in corso d'opera (attualmente) e finali e la realizzazione di un documentario

Inertial sensors for smartphones navigation

The advent of smartphones and tablets, means that we can constantly get informa- tion on our current geographical location. These devices include not only GPS/GNSS chipsets but also mass-market inertial platforms that can be used to plan activities, share locations on social networks, and also to perform positioning in indoor and outdoor scenarios. This paper shows the performance of smartphones and their inertial sensors in terms of gaining information about the user’s current geographical loca- tion considering an indoor navigation scenario. Tests were carried out to determine the accuracy and precision obtainable with internal and external sensors. In terms of the attitude and drift estimation with an updating interval equal to 1 s, 2D accuracies of about 15 cm were obtained with the images. Residual benefits were also obtained, however, for large intervals, e.g. 2 and 5 s, where the accuracies decreased to 50 cm and 2.2 m, respectively

DIRECT PHOTOGRAMMETRY USING UAV: TESTS AND FIRST RESULTS

In recent years, the quality of high resolution acquisition platforms for geomatic applications has decidedly increased, especially in the performance of the sensors devoted to image acquisition.<br><br> The small size of these new sensors combined with the increase in resolution allows them to be easily mounted onto Unmanned Aerial Vehicles (UAVs); in particular, calibrated, very-high-resolution digital cameras for photogrammetric purposes such as digital terrain model (DTM) and digital surface model (DSM) extraction, orthophotos, and map realization have been used. In this case, the UAV performance allows a high quality product to be obtained, considering the pixel size and the accuracy of the DTM/DSM which could be obtained with automatic procedures.<br><br> Several navigation sensors (GPS/GNSS and IMU-MEMS) are embedded into UAVs in order to realize autonomous flight. The quality of these sensors, in terms of accuracy, depends on the model of UAV and its purpose. The navigation solution (position and attitude) is estimated by the internal UAV sensor and can be employed to directly georeference the images, in order to produce an quick and easy description and analysis of the overlooked area. This is a good condition for semi-automatic procedures using a bundle-block photogrammetric approach. But is it possible to realize a direct photogrammetry? And what are the limits?<br><br> Several tests were carried out over different areas and in different conditions using three different UAVs belonging to the Geomatics group of the Politecnico di Torino.<br><br> In this paper, an investigation of the limits of some commercial UAVs is reported, defining a dedicated procedure to valuate their performance, especially considering the use of UAVs for direct photogrammetry

Positioning Techniques with Smartphone Technology: Performances and Methodologies in Outdoor and Indoor Scenarios

Smartphone technology is widespread both in the academy and in the commercial world. Almost every people have today a smartphone in their pocket, that are not only used to call other people but also to share their location on social networks or to plan activities. Today with a smartphone we can compute our position using the sensors settled inside the device that may also include accelerometers, gyroscopes and magnetometers, teslameter, proximity sensors, barometer, and GPS/GNSS chipset. In this chapter we want to analyze the state-of-the-art of the positioning with smartphone technology, considering both outdoor and indoor scenarios. Particular attention will be paid to this last situation, where the accuracy can be improved fusing information coming from more than one sensor. In particular, we will investigate an innovative method of image recognition based (IRB) technology, particularly useful in GNSS denied environment, taking into account the two main problems that arise when the IRB positioning methods are considered: the first one is the optimization of the battery, that implies the minimization of the frame rate, and secondly the latencies due to image processing for visual search solutions, required by the size of the database with the 3D environment images

Ice Detection on Aircraft Surface Using Machine Learning Approaches Based on Hyperspectral and Multispectral Images

Aircraft ground de-icing operations play a critical role in flight safety. However, to handle the aircraft de-icing, a considerable quantity of de-icing fluids is commonly employed. Moreover, some pre-flight inspections are carried out with engines running; thus, a large amount of fuel is wasted, and CO2 is emitted. This implies substantial economic and environmental impacts. In this context, the European project (reference call: MANUNET III 2018, project code: MNET18/ICT-3438) called SEI (Spectral Evidence of Ice) aims to provide innovative tools to identify the ice on aircraft and improve the efficiency of the de-icing process. The project includes the design of a low-cost UAV (uncrewed aerial vehicle) platform and the development of a quasi-real-time ice detection methodology to ensure a faster and semi-automatic activity with a reduction of applied operating time and de-icing fluids. The purpose of this work, developed within the activities of the project, is defining and testing the most suitable sensor using a radiometric approach and machine learning algorithms. The adopted methodology consists of classifying ice through spectral imagery collected by two different sensors: multispectral and hyperspectral camera. Since the UAV prototype is under construction, the experimental analysis was performed with a simulation dataset acquired on the ground. The comparison among the two approaches, and their related algorithms (random forest and support vector machine) for image processing, was presented: practical results show that it is possible to identify the ice in both cases. Nonetheless, the hyperspectral camera guarantees a more reliable solution reaching a higher level of accuracy of classified iced surfaces

Cartographic data harmonisation for a cross-border project development

An essential support for environmental monitoring activities is a rigorous definition of an homogeneous cartographic system required to correctly georeference the acquired data. Furthermore, since the 2007, the European INSPIRE Directive (INfrastructure for Spatial InfoRmation in the European Community) affirms the necessity to harmonize the European maps for permitting cross-border analysis. For satisfying these requirements, the authors have developed a procedure for the cartographic harmonisation in the cross border area studied during in the European project ALCOTRA (Alpes Latines- COopération TRAnsfrontalière) – ALIRHyS (Alpes Latines- Individuation Resources Hydriques Souterraines). It concerns the hydrogeological study of various springs and other water resources in an area between Italy and France including their constitution in a cross-border system. The basic cartographic information is obtained from existing national maps (Italian and French data), which use different reference systems and are produced from different data acquisitions and processes. In this paper the authors describe the methods used to obtain well-harmonised middle-scale maps (aerial orthophotos, Digital Terrain Model and digital maps). The processing has been performed using GIS software or image analysis software in order to obtain useful and correct cartographic support for the monitoring data, even if the obtained maps could be further analysed or refined in future works