1,724,045 research outputs found
Robust surface roughness indices and morphological interpretation
Full text linkGeostatistical-based image/surface texture indices based on variogram (Atkison and Lewis, 2000; Herzfeld and
Higginson, 1996; Trevisani et al., 2012) and on its robust variant MAD (median absolute differences, Trevisani
and Rocca, 2015) offer powerful tools for the analysis and interpretation of surface morphology (potentially not
limited to solid earth). In particular, the proposed robust index (Trevisani and Rocca, 2015) with its implementation
based on local kernels permits the derivation of a wide set of robust and customizable geomorphometric indices
capable to outline specific aspects of surface texture. The stability of MAD in presence of signal noise and abrupt
changes in spatial variability is well suited for the analysis of high-resolution digital terrain models. Moreover, the
implementation of MAD by means of a pixel-centered perspective based on local kernels, with some analogies to
the local binary pattern approach (Lucieer and Stein, 2005; Ojala et al., 2002), permits to create custom roughness
indices capable to outline different aspects of surface roughness (Grohmann et al., 2011; Smith, 2015). In the
proposed poster, some potentialities of the new indices in the context of geomorphometry and landscape analysis
will be presented. At same time, challenges and future developments related to the proposed indices will be
outlined.
Atkinson, P.M., Lewis, P., 2000. Geostatistical classification for remote sensing: an introduction. Computers & Geosciences 26, 361-371.
Grohmann, C.H., Smith, M.J., Riccomini, C., 2011. Multiscale Analysis of Topographic Surface Roughness in the
Midland Valley, Scotland. IEEE Transactions on Geoscience and Remote Sensing 49, 1220-1213.
Herzfeld, U.C., Higginson, C.A., 1996. Automated geostatistical seafloor classification - Principles, parameters,
feature vectors, and discrimination criteria. Computers and Geosciences, 22 (1), pp. 35-52.
Lucieer, A., Stein, A., 2005. Texture-based landform segmentation of LiDAR imagery. International Journal of
Applied Earth Observation and Geoinformation 6, 261–270.
Ojala, T., Pietikäinen, M. & Mäenpää, T. 2002. "Multiresolution gray-scale and rotation invariant texture
classification with local binary patterns", IEEE Transactions on Pattern Analysis and Machine Intelligence, vol.
24, no. 7, pp. 971-987.
Smith, M.W. 2014. "Roughness in the Earth Sciences", Earth-Science Reviews, vol. 136, pp. 202-225.
Trevisani, S., Cavalli, M. & Marchi, L. 2012. "Surface texture analysis of a high-resolution DTM: Interpreting an
alpine basin", Geomorphology, vol. 161-162, pp. 26-39.
Trevisani, S., Rocca, M. 2015. MAD: robust image texture analysis for applications in high resolution geomorphometry. Comput. Geosci. 81, 78–92. doi:10.1016/j.cageo.2015.04.003
Il Respiro di uno spazio / Livella il cielo
No full textl Respiro di uno spazio / Livella il cielo è un progetto di Luca Trevisani ideato nel 2011 e donato al MoRE museum nel 2014. L’artista attraverso la sua metodologia lavorativa; quindi partendo da un dato scientifico, elabora un sistema di tubature che passano attraverso un’edificio, la rete di tubi è sezionata e accoglie la pioggia e le altre intemperie, il livello dell’acqua cambia quindi in base agli eventi atmosferici. L’acqua tra l’altro è anche il soggetto di un libro d’artista di Luca Trevisani, Water Ikebana Stories about solid & liquid things, uscito nel 2014. Il progetto donato al museo non è stato realizzato per la mancanza di un committente e di un luogo adatto allo sviluppo dell’opera.Il Respiro di uno spazio / Livella il cielo is a project created by Luca Trevisani in 2011 and donated to the museum MoRE in 2014. The artist through his working methodology, that starts here from a scientific data, designs a system of pipes that pass through a house, the network of tubes is sectioned and receives the rain and other weather elements, the water level therefore changes according to atmospheric events. The water, among other things, is also the subject of an artist book, Water Ikebana Stories about solid & liquid things (Humboldt Books, 2014), published by Luca Trevisani.
The project donated to the museum has not been realized due to the lack of a commisioner and of a suitable location for the development of the work
Terrain Analysis According to Multiscale Surface Roughness in the Taklimakan Desert
No full textSurface roughness, interpreted in the wide sense of surface texture, is a generic term referring to a variety of aspects and scales of spatial variability of surfaces. The analysis of solid earth surface roughness is useful for understanding, characterizing, and monitoring geomorphic factors at multiple spatiotemporal scales. The different geomorphic features characterizing a landscape exhibit specific characteristics and scales of surface texture. The capability to selectively analyze specific roughness metrics at multiple spatial scales represents a key tool in geomorphometric analysis. This research presents a simplified geostatistical approach for the multiscale analysis of surface roughness, or of image texture in the case of images, that is highly informative and interpretable. The implemented approach is able to describe two main aspects of short-range surface roughness: omnidirectional roughness and roughness anisotropy. Adopting simple upscaling approaches, it is possible to perform a multiscale analysis of roughness. An overview of the information extraction potential of the approach is shown for the analysis of a portion of the Taklimakan desert (China) using a 30 m resolution DEM derived from the Copernicus Glo-30 DSM. The multiscale roughness indexes are used as input features for unsupervised and supervised learning tasks. The approach can be refined both from the perspective of the multiscale analysis as well as in relation to the surface roughness indexes considered. However, even in its present, simplified form, it can find direct applications in relation to multiple contexts and research topics
New Data about the Age and Palaeoenvirnment of the “Pesciara di Bolca” Fossil-Lagerstätte
No full textThe “Pesciara di Bolca” (Verona Province, Northern Italy) is one of the most famous fossil-lagerstätten, known since the mid XVI century for its spectacularly-preserved fish faunas. The latter were extensively studied during past years (e.g. Sorbini, 1972), but little or no attention at all was deserved to the invertebrate microfauna (especially foraminiferans) and to the facies analysis.The larger foraminiferans present in the Pesciara succession were since now neglected because, showing signs of transport, they were considered as reworked. A careful analysis of the field and microfacies features allowed us to conclude the foraminiferans are certainly mostly transported, but with no signs of a real reworking. Moreover, the alveolinas assemblages from all the collected samples belong to the same biozone (Alveolina dainellii Zone, SBZ 11 or Middle Cuisian). The only exception regards some extraclasts in the lower portion of the succession, where silicified alveolinas indicate the underlying SBZ 10 (Alveolina oblonga Zone, Early Cuisian).Previously, the age of the Pesciara was given as Early-Middle Eocene, relying on a single-sample attribution to the nannoplankton zone NP 14 (Discoaster sublodoensis Zone; Medizza, 1975). Now, the alveolina assemblages recognized over the whole succession allow a more stable datation.The facies analysis allowed us to distinguish between strictly autochthonous micritic limestones and allochthonous biocalcarenites-biocalcirudites. The former represents the fish-bearing levels, probably settled within an oxygen-depleted paleoenvironment accounting for the exceptional preservation of fossils. The latter, containing the larger foraminiferans, were probably the result of storm-induced transport from nearby very shallow sea bottom.The presence of emerged lands close to the Pesciara “basin” is testified by several continental fossils of both plants and animals (especially insects). The recent discovery of amber within the Pesciara limestones reinforces this interpretation (Trevisani et al., 2005, in press).ReferencesMedizza F (1975) Il nannoplancton calcareo della Pesciara di Bolca (Monti Lessini). St Ric Giacim Terz Bolca 2:433-444Sorbini L (1972) I fossili di Bolca. Mus Civ St Nat Verona, Verona, 133 ppTrevisani E, Papazzoni CA, Ragazzi E, Roghi G (2005) Early Eocene amber from the “Pesciara di Bolca” (Lessini Mountains, Northern Italy). Palaeogeogr Palaeoclimatol Palaeoecol, in press
Relationships between the Pesciara di Bolca and the Monte Postale Fossil-Lagerstätten (Lessini Mts., northern Italy)
No full textVery close (about 300 m) to the world-famous Pesciara di Bolca Fossil-Lagerstätte, the Monte Postale is the only locality where it is possible to follow a more or less complete sedimentary succession. Despite their closeness, the geological and stratigraphical relationships between the Pesciara and the Monte Postale are still poorly known. This is mainly due to the widespread volcanic and volcanoclastic deposits that, together with tectonic movements of different ages, extensively dismembered and displaced the sedimentary rocks. Therefore, there is no continuity between the limestone of the Pesciara succession and the similar rocks of the Monte Postale, on the opposite side of the valley.At present, the stratigraphy of the Monte Postale succession is still founded on the sketch and description of Fabiani (1914). More recently, Massari & Sorbini (1975) described only a part, about 30 m thick, of the Monte Postale succession.We recently re-examined the whole succession, measuring a composite stratigraphic section made up by two sections (lower and upper) separated by a fault (the Monte Postale fault). The preliminary results of the study of the samples collected revealed that the upper section, bearing quite rich Alveolina assemblages could be dated to the SBZ 11 biozone, i.e. Middle Cuisian (Ypresian). The upper section contains laminated micritic limestone with fish and plants, which are therefore contemporary to the similar limestone of the Pesciara section.The characters of the Monte Postale laminated limestone (MPLL) are in some way different from that of the Pesciara (PLL), because the MPLL bear often bad-preserved fishes (Massimo Cerato, pers. comm.) as compared with the ones coming from the PLL. Moreover, the Monte Postale succession includes a significant thickness of “normal” limestone, very rich in benthonic fossils (especially Alveolina), witnessing the prolonged conditions of normally oxygenated sea bottom, with some intervals of oxygen depletion marked by the MPLL.In the Pesciara section, all the larger foraminifers and other benthic fossils were transported and redeposited in an anoxic environment with terrigenous inputs mainly due to aeolian transport (Schwark et al., 2009).According to these data, we can provisionally conclude that the Monte Postale succession represents a palaeoenvironment more open to marine circulation and consequently better oxygenated than the Pesciara “basin”. More detailed analyses are required to better precise the palaeoenvironmental evolution in the Monte Postale succession.ReferencesFabiani, R. 1914: La serie stratigrafica del Monte Bolca e dei suoi dintorni. Memorie dell’Istituto di Geologia della Regia Università di Padova 2 [1913], 223-235.Massari, F. & Sorbini, L. 1975: Aspects sédimentologiques des couches à poissons de l’Éocène de Bolca (Vérone – Nord Italie). IX Congres International de Sedimentologie, Nice, 55-61.Schwark, L., Ferretti, A., Papazzoni, C.A. & Trevisani, E. 2009: Organic geochemistry and paleoenvironment of the Early Eocene “Pesciara di Bolca” Konservat-Lagerstätte, Italy. Palaeogeography, Palaeoclimatology, Palaeoecology 273 (3-4), 272-285
Le piú antiche piattaforme carbonatiche del Lessini Shelf: biostratigrafia e paleoambiente dello “Spilecciano” di Spilecco (M. Lessini, Provincia di Verona)
No full textScopo di questa nota preliminare è di aggiornare l’attribuzione biostratigrafica e fornire un’interpretazione paleoambientale alle caratteristiche facies dello “Spilecciano” nella località tipo. “Spilecciano” è un termine alquanto controverso per la stratigrafia del Paleogene veneto; fu proposto da Fabiani (1912), che lo considerava un piano equivalente all’Eocene inferiore (intendendo con questo l’intervallo compreso fra il tetto del Cretacico e la base dell’Eocene medio). Fu usato in letteratura fino alla fine degli anni ’60 (Bosellini et al., 1967; Barbieri & Medizza, 1969), dopo essere stato attribuito al Paleocene superiore da Schweighäuser (1953) e Cita & Bolli (1961). Su proposta di questi ultimi autori lo “Spilecciano” fu abbandonato per la frammentarietà degli affioramenti, la potenza estremamente ridotta, la scarsa estensione areale, la peculiarità delle faune e la sostanziale non rappresentatività dell’intervallo di tempo indicato da Fabiani (1912). Lo “Spilecciano” nella località tipo è rappresentato da alcuni piccoli affioramenti (noti in letteratura fin dalla seconda metà dell’ottocento), discontinui ed isolati dalla vegetazione, intorno alla località di Spilecco (toponimo quasi mai indicato nella cartografia ufficiale), a meno di mezzo km a NW di Bolca, nei Lessini veronesi. Si tratta di caratteristici calcari marnosi tufacei rossastri con una ricca fauna a macroforaminiferi, articoli di crinoidi e denti di selaci, intercalati a calcilutiti grigio verdastre a foraminiferi planctonici con sottili livelli a macroforaminiferi e diffusa presenza di glauconite in entrambe le litologie. Dopo un rilievo di tutta l’area intorno al colle di Spilecco, è stata campionata in dettaglio quella che si ritiene essere, attualmente, la più completa e meglio esposta sezione stratigrafica dell’area. Ciò ha permesso di stabilire che i calcari marnosi rossastri rappresentano veri e propri slump risedimentati all’interno di un bacino dove si depositavano le calcilutiti grigio verdastre a foraminiferi planctonici. Le principali evidenze sono rappresentate da ripiegamento degli strati, discordanza angolare con le calcilutiti sottostanti, rapida chiusura laterale degli strati, ecc. Inoltre le calcilutiti sotto e sopra gli slump sono interessate da episodi minori di risedimentazione costituiti da sottili livelli a macroforaminiferi isorientati. La fauna a macroforaminiferi identificata comprende Nummulites bolcensis Oppenheim, N. spileccensis Oppenheim, N. oppenheimi (Rozlozsnik), N. pernotus Schaub, Assilina custugensis (Massieux), Discocyclina tenuis Douvillé, Orbitoclypeus multiplicatus (Gümbel), O. munieri (Schlumberger), O. schopeni (Checchia-Rispoli), Asterocyclina taramellii (Munier-Chalmas).Tra le forme riconosciute, N. bolcensis e N. spileccensis sono specie endemiche, raramente rinvenute al di fuori della località tipo, mentre Asterocyclina taramellii è la più antica specie di questo genere conosciuta nella Tetide europea (Less, 1987). Nonostante l’evidente risedimentazione, l’associazione Nummulites-Discocyclina-Orbitoclypeus-Asterocyclina sembra compatibile con una provenienza di tutti i macroforaminiferi dalla parte più esterna di una piattaforma carbonatica, di cui attualmente non restano altre tracce.L’associazione permette di individuare un’età riferibile alla biozona SB 7 di Serra-Kiel et al. (1998), ovvero all’Ilerdiano medio 1, corrispondente alla base dell’Eocene inferiore. L’età è anche in ottimo accordo con i dati del nannoplancton calcareo (NP 10) e dei foraminiferi planctonici (P5) riportati da Barbieri & Medizza (1969).Si ritiene che tutti questi risedimenti di provenienza neritica rappresentino le uniche testimonianze delle prime piattaforme carbonatiche del Lessini Shelf (la piattaforma carbonatica terziaria del Veneto e del Trentino; Bosellini, 1989), successivamente smantellate dall’erosione e conservate unicamente come risedimenti all’interno del bacino. Si ritiene inoltre che le calcilutiti grigio verdastre a foraminiferi planctonici possano essere ascritte alla Scaglia cinerea nel senso di Trevisani (1994), ossia depositi di peripiattaforma che bordavano queste prime piattaforme. Esiste una sostanziale coincidenza fra l’età di questi risedimenti neritici e il secondo periodo di attività vulcanica terziaria dell’area veneto-trentina (Barbieri et al., 1982; Barbieri et al., 1991), quindi si ritiene verosimile che i materiali vulcanici abbiano funzionato come punti d’innesco di queste proto-piattaforme successivamente erose. BibliografiaBosellini A. (1989): S.E.P.M. Spec. Publ., 44, 3-13. Bosellini A., Carraro F., Corsi M., De Vecchi G. P., Gatto G. O., Malaroda R., Sturani C., Ungaro S. & Zanettin B. (1967) - Note illustrative della Carta Geologica d'Italia, Foglio n. 49 "Verona", sc. 1:100.000. Serv. Geol. Ital. Barbieri G. & Medizza F. (1969): Mem. Ist. Geol. Min. Univ. Padova, 27, 1-36.Barbieri G., De Zanche V., Medizza F. & Sedea R. (1982): Rend. Soc. Geol. It., 4 (1981), 267-270.Barbieri G., De Zanche V. & Sedea R. (1991): Rend. Soc. Geol. It., 14, 5-12. Cita M, B. & Bolli H. M. (1961): Riv. Ital. Paleont., 67, 369-392. Fabiani R. (1912): Atti Acc. Ven. Trent. Istr., 5, 94-125. Less Gy. (1987): Geol. Hungarica, (Palaeont.), 51, 1-373.Schweighäuser J. (1953): Schweiz. Paläont. Abh., 70, 1-97. Serra-Kiel J., Hottinger L., Caus E., Drobne K., Ferrández C., Jauhri A.K., Less Gy., Pavlovec R., Pignatti J.S., Samsó J.M., Schaub H., Sirel E., Strougo A., Tambareau Y., Tosquella J. & Zakrevskaya, E (1998): Bull. Soc. géol. Fr., 169 (2), 281-299.Trevisani E. (1994): Mem. Sci. geol., 46, 1-15
Variogram maps from LiDAR data as fingerprints of surface morphology on scree slopes
No full textHerein, an aerial LiDAR topographic dataset is analysed and interpolated by means of geostatistical techniques in order to examine the morphology of a scree slope area in the Eastern Italian Alps. The LiDAR-derived digital terrain model (DTM) is analysed using variogram maps as spatial continuity indexes. This allowed for evaluation of the reproduction of spatial variability of topography and for the characterization and comparison of different morphological features occurring in the study site. The results indicate that variogram maps efficiently synthesise the spatial variability of topography in a local search window, representing suitable "fingerprints" of surface morphology
Hacking the topographic ruggedness index
Full text linkThe topographic ruggedness index (TRI) is widely adopted for the analysis of digital elevation models, providing information on local surface spatial variability. In this work, the TRI is interpreted according to a geostatistical perspective, highlighting its main characteristics and drawbacks. TRI can be interpreted as an omnidirectional short-range spatial variability index, computed according to a pixel centered perspective. The simplicity and interpretability of the index, free from user-dependent selections, promoted its implementation in several software environments and its application in a wide set of case studies. However, the index has several drawbacks for its application in earth sciences, such as a strong dependency on local slope (it is basically an average adjacent neighbor slope algorithm) and the selection of different lag distances in the computation of spatial variability along the main directions and the diagonal ones. We propose a new metric radial roughness (RRI) in order to solve the main drawbacks of TRI but maintaining its main philosophy (i.e., pixel centered perspective and simplicity of the algorithm). The new index corrects for the differences in lag distances and resolves the dependency on trend using increments of order 2. The code of the index, implemented in R statistical language, and test data are provided with the paper (https://doi.org/10.5281/zenodo.7132160) to promote its implementation in other software environments
Test bichimiques d'identification du Campylobacter pylori en endoscopie pratique au cabinet médical.
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