1,720,974 research outputs found
Registration of single landscape photographs with 3D landscape models
No full textTerrestrial imagery found in public databases is an alternative and complementary data source for environmental studies. Compared to usual data source, such as airborne images, terrestrial pictures may have higher temporal and spatial resolutions. They are especially valuable in studying the past, when airborne acquisitions were more rare or inexistent. Nevertheless, terrestrial image databases are typically imperfectly georeferenced, if at all. Hence, it is difficult to retrieve images of interest in a database. Moreover, georeferencing processes proposed for these images are either totally manual or rely on the existence of a collection of similar and overlapping images. The first is time-consuming and the second is appropriate only for particular sets of images. An alternative and more general georeferencing procedure is the registration of a picture with a landscape model. In this thesis, we propose to use as the reference a 3D virtual globe and our aim is to retrieve the orientation and the location of the camera. The location and orientation of a picture can be computed with correspondences that a user recognizes and clicks in a picture and in an orthoimage. However, these two distinct types of images are difficult to match because of the distortions resulting from the different viewpoints. Hence, we provide a navigation tool to scroll through a 3D model to ease this task. Indeed, to find the orientation of a picture, users typically exploit the skyline which appears only in a 3D view. In imitation, we develop a novel skyline-matching technique, based on Dynamic Time Warping, to compute the fine orientation of a picture. In a second phase, we assess whether the similarities between a 3D synthetic image and real images can be used to compute the orientation of a picture. The matching of real images with a model is challenging. We show how images shared on the web can be inserted in the landscape model to ease the georeferencing. Finally, all of the presented pose estimation schemes assume that every location of the map is as likely to be a shooting spot. However, we show that geographic indicators related to accessibility and morphology are correlated with a database of picture locations. Exploiting these relations, our last contribution is a map of the attractiveness. In this thesis, we observed that pose estimation from the automatic registration of a real image with a landscape model cannot compete with the accuracy reached by an operator or a standard photogrammetric workflow. However, the proposed methods can greatly reduce the operator workload for the manual georeferencing by finding automatically correspondences with a 3D landscape model. Second, they are a valid alternative if the required conditions for Structure-from-Motion are not respected. Finally, the accuracy obtained is sufficient to explore image databases with spatial queries and to add geographic information in the pictures. Registration of landscape images with landscape models has previously received limited attention. The tools developed in this thesis can ease the work of archivists (in the management and provision of efficient image databases), environmental scientists (for the extraction of georeferenced information from pictures) and the general public (to browse collections of augmented images inserted in a virtual globe).LASI
A novel GIS method to determine an urban centrality index applied to the Barcelona metropolitan area
Get PDFEvents occurring in a city, such as car accidents, attacks on the security or activities locations are channelled in the urban network. The goal of this report is to provide a GIS tool able to compute densities and diversities in a network space rather than in the euclidean one. The network space created to support these calculations is a shortest path tree for a given bandwith. On the basis of this shortest path tree, three parameters are calculated: the density and the diversity of activities and the density of edges. The case study of this report is the city of Barcelona. The activities of this city were projected on the network. Indeed, activities like other events in the urban space tend to follow the network. The Human Space Lab (HSL) of the Politecnico di Milano (IT) has applied its Multiple Centrality Assessment to Barcelona's network. Thus, edges become a value of centrality. The network density of the edges presented in this report will take into account these attributes such as the value of population used in other available GIS density tools. The further idea, is to weigh the events (activities or edges) by their distances, as in a standard kernel density estimation. The network approach reveals a spatial distribution of the values sensitive to the favourite direction of the network. The diversity measured along the network make out particular area of the city as residential or commercial zones.LASIGSIE-
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Conception d'un outil informatique pour la diusion de bonnes pratiques en production propre et symbioses industrielles
No full textPour diminuer l'impact environnemental des industries, deux approches sont aujourd'hui conseillées en écologie industrielle : les symbioses industrielles et les techniques de production plus propre. Pour mettre en pratique de telles approches, il faut réaliser un travail d'identification d'opportunités, d'évaluation de faisabilité et d'élaboration de plan d'action. Un outil informatique facilitant ce travail peut promouvoir ces concepts et encourager les entreprises à investir dans de telles démarches. Mais il peut aussi contribuer au partage de connaissances et d'expériences en centralisant tous les projets existants et les techniques efficientes sur une même plateforme. Ce projet de master présente le concept d'un tel outil. Tout d'abord, les fonctionnalités répondant aux besoins détectés sont identifiées puis un modèle conceptuel est élaboré. Une suggestion de technologies à utiliser est par la suite proposée pour guider les développeurs. Cet outil, contrairement à la majorité des logiciels existants, propose des fonctionnalités SIG sur l'exemple de l'application SymbioGIS, référence pour la conception du programme. Un prototype a été développé au cours du projet pour proposer de nouvelles fonctionnalités spatiales. Cette implémentation a ainsi attesté du bon fonctionnement des technologies proposées et a démontré l'intérêt et le potentiel des systèmes d'informations géographiques dans un tel outil.LASI
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
sMapShot ::Georeferenzierung historischer Landschaftsbilder durch Crowdsourcing
No full textHistorische Landschaftsbilder haben einen hohen historischen und geografischen Wert. Sie enthalten genaue Informationen über Landschaftsveränderungen und sind eine wertvolle Informationsquelle für Raum- und Stadtplaner, Geographen und Historiker. Grosse Mengen von historischen Landschaftschaftsbildern sammeln derzeit Staub in vielen Archiven der Schweiz. Des weiteren fehlen effiziente Suchmaschinen in Bildarchiven, welche schon Landschaftsbilder digitalisiert haben. Ein Grund dafür ist, dass die Bilder nicht georeferenziert sind oder nur grob nach einem Ortsnamen, der in den Metadaten des Bildes vorkommt, katalogisiert sind. In unserem Projekt wollen wir das geographische Wissen von freiwilligen Teilnehmern nutzen, um die genaue 3D-Georeferenzierung von historischen Bildern herauszufinden. Diese Georeferenzierung wird dann verwendet, um einen virtuellen Globus der Vergangenheit aufzubauen und um die genauen Ortsnamen zu berechnen, die im Bild sichtbar ist
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