1,720,986 research outputs found
Land use/cover change in the Tam Giang - Cau Hai Lagoon (Central Vietnam) by means of SPOT 5, Aster and Landsat images
Full text linkAbstract Number: EGG01617
A Geomatics Approach to Multitemporal Shoreline Analysis in Western Mediterranean: The Case of Platamona-Maritza Beach (Northwest Sardinia, Italy)
No full textThis study examines the shoreline change evolution at two spatiotemporal scales over ca. 18 km of Platamona-Maritza beach (northwest Sardinia, Italy). A multitemporal dataset spanning the period 1955–2010 was used and made up of archival aerial photographs, orthophotos, satellite imagery, light detection and ranging data, terrestrial laser scanner, Global Positioning System, and recent and historical topographic maps. We integrated this dataset by implementing a repeatable processing procedure, for which the global sensitivity for shoreline change estimation was evaluated (ca. 10 m as a product of time interval and change rate). The applied methodology indicates that the wet/dry boundary can be used as a good shoreline proxy. It is also demonstrated how reliable shoreline positional uncertainty (from 1.9 to 8.6 m) can be estimated whenever a large set of multitemporal data is available and geomatic tools are properly integrated.
Results showed how shoreline evolutionary trends affected the entire coastal zone and roughly migrated from east to west, with the largest rates between 1970 and 2000. Where long-term analysis provided higher erosion rates, a sediment volumetric change was estimated, although only for a 2-year window and for a 300-m-wide stretch of beach. An analysis of geomorphic features along the coast also indicates variable longshore drift direction as a consequence of changes in a combination of wind, wave, and current regimes. A direct relationship between the evolutionary trend of hydrometric and pluviometric data recorded at the study site highlight that, although rainfall regime is nearly constant, average discharge of main rivers underwent a dramatic decrease since 1965 in conjunction with land use change and upstream dam construction for agriculture and urban development. Therefore, it has been argued that river sediment supply also was reduced; hence, besides other natural and anthropogenic causes, it likely influenced erosion and accretion events in the southern sector of the Gulf of Asinara
Assessment of land-use and land-cover changes from 1965 to 2014 in Tam Giang-Cau Hai Lagoon, central Vietnam
No full textThis study integrates the use of multi-source and multi-resolution remote sensing, topographic and fieldbased
datasets to quantify land-use and land-cover (LULC) changes along a coastal stretch of Thua Thien Hue Province (central Vietnam).
The LULC change analysis involves the Tam Giang-Cau Hai lagoon, the largest lagoon system in Southeast Asia, which is running nearly 70 km along the coast and having about 22,000 ha of water surface. The LULC change analysis was performed by computer-aided visual interpretation for 5 years (1965, 1989, 2000, 2006 and 2014) using satellite imagery from LANDSAT MSS, TM, ETMþ and 8, ASTER and
SPOT5. National topographic maps were also used for the 1965 and 2000 years.
To adequately represent the LULC features and peculiarities of central Vietnam coastal areas, an adapted CORINE Land Cover nomenclature was used where new 3rd and 4th level classes were adopted. Due to their intrinsic relative high spatial and radiometric resolution, SPOT5 images from 2006 were assumed as a reference for interpretation keys and first delineation. Changes were mapped by editing
those vectors representing features which underwent LULC change prior or after 2006. Spatial and temporal changes were analyzed by post-classification approach and validated by ground truth information. High detail object-based classification was finally performed to infer the capability of medium spatial resolution imagery for extracting cadastral scale pond maps. The accuracy of classification was checked by a polygon by polygon comparison with an existing aquaculture facility inventory.
Five LULC maps were obtained by applying a legend of 21 classes including two newly defined: “Aquaculture ponds” and “Mangrove forest”. The overall classification accuracy of the LULC map is 85% while the KHAT statistics 0.81 for the year 2006. Accuracy of the object-based aquaculture facilities classification is 84% or better for the SPOT5 imagery and 47.9% for the ASTER imagery. The study provides
a synoptic LULC representation for the largest lagoon system of Southeast Asia and delivers quantitative
estimates of main changes occurred during the last 50 years. Moreover, it reveals the adaptability of the
CORINE Land Cover method outside European environment. Finally, SPOT5 provides good results to map
aquaculture features at cadastral scale, even if in some circumstances (e.g. tidal areas), the integration
with higher spatial resolution multispectral sensors should be envisaged.</br
Analisi spettrale di dati telerilevati ETM+ e ASTER nei granitoidi ercinici dell'Arcipelago della Maddalena (Sardegna)
No full textAi fini della fotointerpretazione geologica dell'Arcipelago della Maddalena, il presente lavoro ha sperimentato le potenzialità dell'analisi spettrale di immagini ASTER (Advanced Spaceborne
Thermal Emission and Refleclion Radiomefer) ed ETM+ (Enhanced Thematic Mapper Plus). L' integrazione dei risultati dell'analisi spettrale e della fotointerpretazione dei dati satellitari con il tradizionale rilevamento in situ, ha consentito di discernere le unità metamorfiche da quelle magmatiche granitiche e queste ultime al loro interno. È stato inoltre possibile cartografare i sistemi
filoniani principali, distinguendone la natura litologica. L'analisi spettrale ha evidenziato la buona corrispondenza tra le firme spettrali ricostruite a partire dalle immagini, quel1e acquisite sui
campioni raccolti in campagna e quelle appartenenti a librerie di riferimento
Analisi spettrale ed interpretazione di immagini ETM+ ed ASTER come supporto al rilevamento geologico del Foglio 412 – Isola Maddalena
No full textImmagini Landsat ETM+ e NDVI differencing per lo studio della deforestazione nel Mato Grosso meridionale (Brasile).
No full textContribution of geological remote sensing to the analysis of geothermal sites
No full textAbstract Number: GTR01606
Studio multitemporale di uso e copertura del suolo della laguna di TamGiang - Cau Hai (Vietnam centrale) attraverso immagini multispettrali SPOT 5, Aster e Landsat ETM+
No full textMultitemporal shoreline change and erosion/accretion rates in North Sardinia, by integration of digital photogrammetry, remote sensing and GPS
No full textApplicazione del metodo di NDVI differencing per la valutazione della deforestazione nel Mato Grosso meridionale (Brasile).
No full text- …
