1,720,996 research outputs found
VERIFICA DEI PARAMETRI DI TRASFORMAZIONE DA WGS84 AL SISTEMA NAZIONALE (ROMA40-GAUSS-BOAGA)
No full textMultiscale representation: a data generalization workflow and quality evaluation experience in GIS enviroment
No full textConcerning geographic data representation, what a user need is specific tools for the representation and evaluation of the data on which the decision process relies. In cartographic applications, users need to deal with maps of the same geographic region at different levels of abstractions. Usually it’s used to maintain one database per level detail; a multiscale representation GIS would allow storing all original geographical information in a single database, and enforce the consistency of the different representations through appropriate, automatic generalization processes.
In this paper we deal with the problem of geographic data generalization, beginning from a generalization workflow by improving specific routines.
To aim the goals of the generalization process, we used the ESRI ArcGIS 8.1 platform. Inside this enviroment it have been implemented some generalization functionalities by improving appropriate ruotines in Visual Basic language. After a presentation of the generalization workflow, all cartographic constraints, of geometric, topological and semantic nature, governing the generalization process, are specified. In the next step these constraints will be translated into tools for assessing the need and the quality of generalization solutions. These tools are associated with a particular data model. For that data model the constraints can be best translated to measures and generalization algorithms and parameterized. This framework is based on constraints that are used to control the process and represent the user requirements in a way the system can manage to reach a quality close to these requirements; it reflects the idea that more than one acceptable solution may exist to a given generalization problem. The goal was the production of a topographic map at scale 1:50000, 1:100000 and 1:250000 from the “Carta Tecnica Regionale”, CTR, (official regional cartography) of the “Regione Autonoma della Sardegna”, RAS, (Regional Administration of Sardinia), at scale 1:10000, in a GIS environment.
According with the official national and international standards, we provide the definition of the characteristics and associated quality evaluation tool to be used in order to validate the geographic data
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Survey of a local network to check the stability of marker no 7545 situated in the Cagliari Astronomical Observatory for the Wegener/Medlas project
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