1,720,968 research outputs found
Tecniche di rilievo laser scanner a supporto del progetto di restauro conservativo dei beni culturali. L'esempio del Castello di Siviller e della Torre campanaria di Mores
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Pre-processing of high resolution satellite images for sea bottom classification
No full textIn order to monitor the coastal-sea environment it is necessary to check variations of the coastal line as well as the sea bottom. There are techniques for using remote sensing as a technique for the extraction of bathymetric information. However, these techniques require preliminary radiometric image processing in order to fulfill the model constraints. More precisely, atmospheric effects must be removed together with the water column correction in order to achieve radiometric values that are only representative of the sea depth and to homogenize the upwelling response from different bottom types. If sun-glint is present, the effect of the sun beams reflecting on the sea surface, it has to be corrected by a special procedure. This work is concerned with pre-processing the images, via the development of a module in IDL (Interactive Data Language). This module was subsequently embedded in the ENVI menu system. The model was applied to Ikonos and WorldView-2 scenes, representing respectively the Poetto beach near the city of Cagliari and the littoral of Marina di Altidona (the Marches, Italy). The results of pre-processing were evaluated using an unsupervised classification
An example of a tourist Location Based Service (LBS) with Open Source Software
No full textLocation-based services (LBS) provide information and data to the
user based on geographical position. These services are usually
based on a communication network and one or more positioning
technologies, combined with geographical information systems
which collect the information and present it to the end user. An
LBS service is implemented within an infrastructure which must
contain at least these five elements: a mobile device (e.g. a cell
phone or PDA), a communications network (GSM, GPRS, UMTS), a
positioning component (GPS receiver), a service provider and
finally, a data provider. On an international level, both the ISO
Technical Committee 211 and the Open Geospatial Consortium
(OGC) issued standards and specifications regarding the LBS
services. This work concerns the development of a client–server
framework compliant with the OpenLS OGC standard and built
entirely with free and/or open-source software. The LBS service is a
tourist information application for the city of Cagliari in Sardinia
(Italy)
Un servizio LBS (Location Based Service) info turistico con software Open Source
No full textIl lavoro che si presenta si colloca nell’ambito dei servizi noti come LBS (Location Based Services) e in particolare lo studio ha affrontato le problematiche legate alle diverse componenti di cui questi sono cosituiti e alla standardizzazione ed interoperabilità di un servizio di questo tipo. Si tratta di servizi a valore aggiunto che utilizzano la conoscenza della localizzazione geografica di un utente mobile per fornire dinamicamente a quest’ultimo risposte appropriate alle sue esigenze quali informazioni, mappe ecc..
A livello internazionale sia l’ISO/TC 211 sia l’Open Geospatial Consortium (OGC) hanno emanato direttive e standard per i servizi LBS. L’ISO/TC 211 si è occupata degli standard LBS nei documenti 19132 (Location based services possible standard), 19133 (Location based services tracking and navigation) e 19134 (Multimodal location based services for routing and navigation), mentre l’OGC si è occupata degi LBS emanando lo standard OpenLS.
L’applicazione pratica degli LBS è stata sviluppata in sistemi software da diverse società sia commerciali sia orientate al free/open software. I software di tipo commerciale tuttavia non pubblicizzano alcuna adesione allo standard OpenLS benché alcuni dei produttori siano essi stessi membri dell’OGC.
Per tali motivi, il gruppo di ricerca ha deciso di realizzare una piattaforma client-server aderente allo standard OpenLS. L’applicazione di esempio su cui è stata sviluppata la ricerca è un sistema info-turistico in cui l’utente può richiedere informazioni sulla locazione in cui si trova. Secondo la terminologia dell’OpenLS, questa applicazione si configura come caso particolare di Reverse Geocoding.
E’ stato sviluppato, quindi, un server in linguaggio python che implementa parte della specifica Location Utility Service per l’esecuzione dell’operazione di Reverse Geocoding. Per il lato client è stata implementata un’applicazione basata sul visualizzatore cartografico GvSIG Mini, che consenta di interrogare il servizio di Reverse Geocoding
INTEGRATION OF GEOMATIC TECHNIQUES FOR THE URBAN CAVITY SURVEY
No full textCagliari, county seat of Sardinia Region (Italy), situated in the southern part of the island, is characterized by a subsoil full of
cavities. The excavations in fact, which lasted more than 4000 years, had a great development due also to the special geological
characteristics of the city subsoil. The underground voids, which the city is rich in, belong to different classes such as hydraulic
structures (aqueducts, cisterns, wells, etc.), settlement works (tunnels, bomb shelters, tombs etc.) and various works (quarries, natural
caves, etc.). This paper describes the phases of the survey of a large cavity below a high-traffic square near the Faculty of
Engineering in the city of Cagliari, where the research team works. The cave, which is part of a larger complex, is important because
it was used in the thirteenth century (known as the Pisan age) as a stone quarry. There are traces of this activity that have to be
protected. Moreover, during the last forty years the continuous crossover of vehicles cracked the roof of the cave compromising the
stability of the entire area. Consequently a plan was developed to make the whole cavity safe and usable for visits. The study of the
safety of the cave has involved different professionals among which geologists, engineers, constructors. The goal of the University of
Cagliari geomatic team was to solve two problems: to obtain geometrical information about the void and correctly place the cave in
the context of existing maps. The survey and the products, useful for the investigation of the technicians involved, had to comply
with tolerances of 3 cm in the horizontal and 5 cm in the vertical component. The approach chosen for this purpose was to integrate
different geomatic techniques. The cave was surveyed using a laser scanner (Faro Photon 80) in order to obtain a 3D model of the
cave from which all the geometrical information was derived, while both classic topography and GPS techniques were used to
include the cave in the city map
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