1,720,988 research outputs found
GNSS contribution to monitor severe rainfalls: an innovative procedure for wide and orographically complex area with existing infrastructures
No full textThe research activity concerned the development of an innovative methodology to monitor the content of Precipitable Water Vapour (PWV), starting from Zenith Tropospheric Delay (ZTD) estimations obtained from GNSS permanent stations, and Pressure (P) and Temperature (T) observed in meteorological sensors networks. In particular, an automatized procedure, named G4M (GNSS for Meteorology), for preparing and elaborating the data collected from the existing infrastructures and for producing PWV maps will be presented. The G4M procedure has been applied to study two critical events occurred on Genoa city; this analysis led to the definition of a “Heterogeneity Index”, accounting for PWV spatial variability, which has been considered a promising indicator to highlight and locate severe meteorological events in time and space. Additionally, ZTD and PWV time series have been obtained for selected GNSS Permanent Stations in order to identify recognizable patterns in ZTD/PWV that can be related to the occurrence of severe meteorological events
Modellazione 3D del substrato roccioso e del livello di falda mediante interpolazione di punti in GRASS.
No full textL’obiettivo del presente lavoro è la generazione delle superfici del substrato roccioso e del
livello di falda mediante interpolazione di dati puntuali di profondità rispetto alla superficie del
DTM, al fine di modellarne gli andamenti nella zona di S. Stefano d’Aveto (GE). A tal scopo sono
state utilizzate alcune delle tecniche di interpolazione implementate in GRASS (VORONOI, IDW,
SPLINE, B-SPLINE), al variare dei parametri tipici di ciascun metodo.
Nell’ambito di questo studio sono stati sviluppati due possibili approcci che danno origine a
superfici con analogo andamento globale ma che, a livello locale, presentano delle differenze.
Il primo approccio si basa sul calcolo delle quote effettive dei punti del substrato e della falda,
essendo nota soltanto la profondità dei punti rispetto alla superficie del terreno, e sulla loro
successiva interpolazione. Tale approccio produce superfici lisce e maggiormente sensibili
all’azione dei parametri tipici di ogni metodo di interpolazione.
Il secondo approccio, che consiste nell’interpolazione dei dati originari e nella successiva
sottrazione della superficie ottenuta al DTM, produce superfici corrugate, che ricalcano
l’andamento del DTM stesso. Tali differenze a livello locale sono chiaramente identificate dalla
valutazione della derivata prima in direzione N-S e in direzione E-O delle superfici ottenute con
i due diversi approcci.
Una volta ottenute le superfici interpolate, sono state effettuate valutazioni di tipo qualitativo
(assenza di cuspidi e altre singolarità, ritenute irrealistiche) e quantitativo valutazione dello
scarto quadratico medio e cross-validazione) per giustificare in maniera critica la scelta del
metodo di interpolazione e dei parametri più adatti a descrivere l’andamento del substrato
roccioso e del livello di falda, evidenziando caratteristiche, pregi e difetti di ciascuna
metodologia affrontata
3D reconstruction of the Pollera cave, Italy
No full textThe Pollera cave is situated in the region of Liguria, Italy, and it is the subject of a strategy aimed at improving and promoting tourism in the area. In this project, 3D laser scans of some of the more easily accessible cave rooms were needed to create multimedi products such as movies, images and scenes for 3D virtual tours, and to generae geocartographic products for tourist excursions. To achieve this, the cave was scanned using a Z+F IMAGER 5010 high-precision laser scanner. Surveying and data processing proved to be particularly difficult and costly due to the underground environment, but by using free and open-sourced software a fully textured 3D model was successfully generated.The Pollera cave is situated in the region of Liguria, Italy, and is the subject of a strategy aimed at improving and promoting tourism in the area. In this project, 3D laser scans of some of the more easily accessible cave rooms were needed to create multimedia products such as movies, images and scenes for 3D virtual tours, and to generate geocartographic products for tourist excursions. To achieve this, the cave was scanned using a Z+F IMAGER 5010 high-precision laser scanner. Surveying and data processing proved to be particularly diffi cult and costly due to the underground environment, but by using free and open-sourced software a fully textured 3D model was successfully generated
HIGH-PRECISION LASER SCANNING FOR CAVE TOURISM 3D Reconstruction of the Pollera Cave, Italy
No full textAtmospheric precipitable water vapor tracking during 2023-2025 Amerigo Vespucci world tour
No full textThe 2023–2025 world tour undertaken by the Italian Navy’s Amerigo Vespucci vessel constitutes a unique and valuable opportunity to perform continuous monitoring of atmospheric Precipitable Water Vapor (PWV) at fine spatial and temporal resolutions. PWV represents a critical parameter for accurately monitoring and forecasting extreme precipitation events, assessing climate variability, and improving the positioning accuracy of Global Navigation Satellite Systems (GNSS). In this context, the installation onboard of a GNSS receiver equipped with external geodetic antenna and a weather station opened the possibility to track PWV along the world tour route with the final aim to to develop a comprehensive geo-DataBase (geoDB)of PWV values, spatially and temporally referenced to the ship trajectory across the globe. The GNSS-derived PWV values will be compared with outputs from meteorological models in order to assess their consistency, to evaluate the reliability of the derived results, and to consider the potential future assimilation into meteorological models
Toward a Sustainable Estimation of Significant Wave Height Through Photogrammetry
No full textMonitoring Sea wave conditions is critical for maritime safety, coastal management, and understanding ocean-atmosphere interactions. In this study, we introduce a stereophotogrammetric system for the estimation of significant wave height (SWH), leveraging a portable and flexible optical approach for reconstructing three-dimensional sea surface topography. The proposed method employs a dual-camera system with synchronized triggering, calibrated via MATLAB stereo toolbox, and supported by a robust image processing pipeline capable of generating disparity maps and dense point clouds. This system offers an innovative, non-invasive, and scalable alternative to conventional wave monitoring tools such as buoys and radar. We present preliminary results from controlled experiments and discuss ongoing developments, including further deep-learning integration for stereo matching and potential fusion with GNSS data for georeferencing. This photogrammetric strategy aligns with the goals of the UN Agenda 2030 for Sustainable Development by promoting accessible, eco-friendly technologies for environmental observation
Metodologia per la valutazione della massima risalita plano-altimetrica del moto ondoso su spiaggia per via fotogrammetrica e GPS
No full textThe present work shows the survey and the analysis of the results of a measurement campaign for the calculation of the maximum planimetric and altimetric lift of the wave motion on the beach in particular marine situations with respect to the mean sea level condition. The run-up measurement was carried out through different surveying techniques, to integration and verification: stereoscopic and monoscopic photogrammetry, GPS satellite positioning. The 3D model of the beach, the orthophotos and the GPS tracks related to both the reference line of the shoreline in normal conditions and the line of maximum expansion of the wave on the beach have been so obtained. The integration of the survey techniques has allowed a satisfactory assessment of the maximum planimetric and altimetric lift of the wave
A procedure to manage open access data for post-processing in GIS environment
No full textDataBases (DB) are a widespread source of data, useful for many applications in different scientific fields. The present contribution describes an automatic procedure to access, download and store open access data from different sources, to be processed in a GIS environment. In particular, it refers to the specific need of the authors to manage both meteorological data (pressure and temperature) and GNSS (Global Navigation Satellite System) Zenith Total Delay (ZTD) estimates. Such data allow to produce Precipitable Water Vapor (PWV) maps, thanks to the so called GNSS for Meteorology (G4M) procedure, developed through GRASS GIS software ver. 7.4, for monitoring in time and interpreting severe meteorological events. Actually, the present version of the procedure includes the meteorological pressure and temperature data coming from NOAA’s Integrated Surface Database (ISD), whereas the ZTD data derive from the RENAG DB, that collects ZTD estimates for 181 GNSS Permanent Stations (PSs) from 1998 to 2015 in the French-Italian boundary region. Several Python scripts have been implemented to manage the download of data from NOAA and RENAG DBs, their import on a PostgreSQL/PostGIS geoDB, besides the data elaboration with GRASS GIS to produce PWV maps. The key features of the data management procedure are its scalability and versatility for different sources of data and different contexts. As a future development, a web-interface for the procedure will allow an easier interaction for the users both for post-processing and real-time data. The data management procedure repository is available at https://github.com/gtergeomatica/G4M-dat
Influence of Data Preprocessing and Optimization in Multivariate Statistical Analysis of Landslide Susceptibility
No full textAs part of the PNRR – Extended Partnership RETURN, the research group is developing a procedure for producing landslide susceptibility maps in a GIS (Geographic Information System) environment. The use of the statistical technique of Logistic Regression has proved suitable for the purpose, but the reliability of the resulting models depends greatly on the input data and their pre-processing. To make the proposed procedure effectively usable by land managers, transferable to different areas, and allowing for the comparison of different scenarios, it is necessary to define a minimum standard for the input data, as well as some specifications for their preprocessing. The present work, based on the case study of the Province of Savona (IT), identifies the basic data requirements, and provides instructions for the preparation of spatial datasets (relative to the Italian territory) and for the processing flow for the effective use of Logistic Regression for statistical landslide prediction
Il contributo della geomatica alla valutazione delle allerte meteorologiche
No full textThere are various techniques, models and measures of atmospheric parameters used in weather forecasting: from observations on the ground to measures by weather balloons, from satellite images to weather radar. It’s well known that it is possible to estimates tropospheric zenith delay (Zenith Total Delay, ZTD) from the analysis of the signal observed by a network of GNSS Permanent Stations.
This paper analyze main passages for the assessment of Precipitable Water Vapor (PWV) from ZTD estimates, integrated by measurements of pressure and temperature on the ground, the latter described by the Digital Terrain Model (DTM).
The proposed solutions allow to create spatial-temporal maps of the potentially precipitable water vapor content, either as contribution to an atmospheric monitoring, that to provide useful information the triggering of predictive models to support decisions for nowcasting.
The application to a case study particularly significant for the city of Genoa will show maps of the evolution of these parameters in a territory orographically complex as that of the Alps
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