1,720,955 research outputs found
The contribution of GIS in flood mapping. Two approaches using open source GRASS GIS software
No full textThe first step of a risk assessment analysis is the evaluation of flood-prone areas. Its importance is considered for both managing and planning emergency activities, such as hydraulic risk reduction management, and also town planning. Nowadays, using GIS technology for risk assessment analysis is very common. However, it is not widely used for defining inundated areas. LiDAR data, such as Digital Elevation Models (DEM), makes GIS numerical models attractive methods for obtaining a flooded area automatically. Using GIS tools, is beneficial for effective processing and accuracy assessment in comparison to the traditional methods which are based on topographic maps and field surveys.
A first approach (Federici & Sguerso, 2007; Marzocchi et al. 2009) is the use of a GIS module in order to create perifluvial flood maps, having as prerequisites (i) the conformation of the river floodplain by a high resolution DEM and (ii) a water surface profile along the river axis calculated for a given water discharge through a generic one-dimensional (1D) hydraulic model (HEC-RAS, Basement, MIKE 11, etc). On the other hand, a second approach is the use of a 2D model GIS embedded in order to create flooded areas due to a dam break (Cannata & Marzocchi, 2012). This module solves the conservative form of the 2D Shallow Water Equations (SWE) using a Finite Volume Method (FVM). The intercell flux is computed by a one-side upwind conservative scheme extended to a 2D problem (Ying et al., 2004). The new developed GIS module gives as an output maximum intensity maps which can be directly used during the risk assessment process. Both models implemented in GRASS GIS software (GRASS, 2013) and two new commands (r.inund.fluv and r.damflood) have been created. They are all available on the official GRASS website and they are distributed under the terms of the GNU General Public License (GPL).
In this work we present a comparison between the two models mentioned above. We analyse the possibility of integrating these two approaches. We intend to use the 1D model, GIS embedded if possible, to calculate the water surface profile along the river axis and the 2D numerical one to analyse inundation beside the river levees
Comparison of one-dimensional and two-dimensional GRASS GIS models for flood mapping.
No full textThe first step of a risk assessment analysis is the evaluation of flood-prone areas. Nowadays, using Geographic Information System (GIS) technology for risk assessment analysis is very common. However, it is not widely used for defining inundated areas. LiDAR data, such as digital elevation models (DEM), makes GIS numerical models attractive methods for obtaining a flooded area automatically. A first approach (Federici & Sguerso, 2007; Marzocchi, 2009) uses a GIS module in order to simulate perifluvial flood maps, having as prerequisites (i) the conformation of the river floodplain by a high-resolution DEM and (ii) a water surface profile
along the river axis calculated for a given water discharge through a generic one-dimensional (1D) hydraulic model (HEC-RAS, Basement, MIKE 11, etc.). On the other hand, a second approach uses a GIS-embedded two-dimensional (2D) model in order to simulate flooded areas due to a dam break (Cannata&Marzocchi, Nat Hazards 61(3):1143–1159, 2012).
This module solves the conservative form of the 2D shallow water equations (SWE) using a finite volume method (FVM).
We present a comparison between the two models mentioned above, and we analyse the possibility of integrating these two approaches
Gestione e pubblicazione di dati geografici con GFOSS software: l'esempio della Provincia di Imperia nell'ambito del progetto strategico Alcotra-RiskNat.
No full textThe effective use of information and communication technologies (ICT) is an evolutionary trend which many countries of the European Union (EU) are currently experiencing, including Italy. In this contribution, we deal with the options of applying GRASS GIS and other Geographic Free OpenSource Software (GFOSS) in the process of informatisation of public administration (PA).
The activities have been carried out on the behalf of the EU Alcotra - RiskNat strategic cross-border project, under the guidance of the Imperia Province (Liguria, Italy). The main focus is the design and creation of a geographical database (DB) for managing spatial and non spatial information, using PostgreSQL/ PostGIS, GRASS and Quantum GIS (QGIS).
A few geowebservices have been published according to the OGC Web Services (OWS) standards using the GeoServer platform. INSPIRE guidelines and specifications have been implemented for the related metadata files. The aim is to enable interoperability and reuse of geographical data and services which are also inserted as a layer in the RiskNat geoportal.
A digital DVD ATLAS has been created for further navigation and interrogation of the various thematic layers of the cross-border basin of Roia river, using OpenLayers
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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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