Automatic Representation of Geographical Data from a Semantic Point of View through a New Ontology and Classification Techniques     

Rainer Larin Fonseca  Eduardo Garea Llano 《Transactions in GIS》2011,15(1):61-85

Providing Geographical Information Systems with mechanisms for processing geo‐data based on their semantics may help to solve problems like heterogeneity. This is because GIS could process geo‐data focusing on their meaning and not on their syntax and/or structure. An important aspect for achieving these objectives is the establishment of an automatic means of correspondence between geo‐data and their conceptualization in Higher Levels Ontologies (HLO). In this article, a new type of Ontology is proposed (Data‐Representation Ontology (DRO)). This Ontology describes the semantic embedded in geo‐data, which cannot be represented in current types of Ontologies. Across this Ontology, heterogeneous geographical data can be integrated in the semantic space contributing positively to the development of solutions for the problems of interoperability between heterogeneous systems. Likewise, we propose a new method for the automatic generation of the DRO and its interrelationships with HLO, based on pattern classification techniques. The experiments show that once the DRO is generated, the classifier can classify all data correctly. Thus, these data are semantically enriched. Moreover, this article shows how the topological relationships can enrich the semantics in the generated Ontology and increase the effectiveness of spatial analysis.  相似文献   

Ecological quality assessment of small estuaries from the Portuguese coast based on fish assemblages indices     

Cardoso I  Pais MP  Henriques S  da Fonseca LC  Cabral HN 《Marine pollution bulletin》2011,62(5):992-1001

The importance of establishing the ecological quality of estuarine systems has been widely acknowledged and led to the development of several fish community-based multimetric indices. Nevertheless, a question rose about the accuracy of these tools when natural disturbance is acting upon the organization of the systems’ communities. Four multimetric indices were used to examine their ability to differentiate the ecological status of five small estuarine systems (southern Portugal), and also to test if they reflected the level of anthropogenic pressures. Fish assemblages from Mira, Odeceixe and Aljezur (in the Southwest coast), Gilão and Bensafrim (in the South coast) estuaries were sampled seasonally for one year, and anthropogenic sources of pressure were identified and quantified. We found that although the applied indices provided information on ecological condition differentiation among systems, they are unable to explain different classes of ecological status in systems with equivalent pressure levels.  相似文献   

Methods to determine the angular resolution of the HEGRA extended air shower scintillator array     

M. Merck  A. Karle  S. Martinez  F. Arqueros  K. H. Becker  M. Bott-Bodenhausen  R. Eckmann  E. Faleiro  J. Fernandez  P. Fernandez  V. Fonseca  V. Haustein  G. Heinzelmann  I. Holl  F. Just  F. Krennrich  M. Kühn  E. Lorenz  H. Meyer  N. Müller  R. Plaga  J. Prahl  M. Probst  M. Rozanska  M. Samorski  H. Sander  K. Sauerland  C. Sesea  W. Stamm 《Astroparticle Physics》1996,5(3-4):379-392

A precise knowledge of the angular resolution of scintillator arrays used to observe extended air showers (EAS) is of key importance in the search for VHE/UHE γ point sources. Four independent methods have been used to determine the mean resolution for which a value of ΔΘ₆₃ of 0.8°(1.0°) at a proton threshold of 50 (40) TeV has been found for the HEGRA EAS-array.  相似文献   

Reference data enhancement for geographic information retrieval using linked data   总被引：1，自引：0，他引：1       下载免费PDF全文

Tiago H. V. M. Moura  Clodoveu A. Davis Jr.  Frederico T. Fonseca 《Transactions in GIS》2017,21(4):683-700

Gazetteers are instrumental in recognizing place names in documents such as Web pages, news, and social media messages. However, creating and maintaining gazetteers is still a complex task. Even though some online gazetteers provide rich sets of geographic names in planetary scale (e.g. GeoNames), other sources must be used to recognize references to urban locations, such as street names, neighborhood names or landmarks. We propose integrating Linked Data sources to create a gazetteer that combines a broad coverage of places with urban detail, including content on geographic and semantic relationships involving places, their multiple names and related non‐geographic entities. Our final goal is to expand the possibilities for recognizing, disambiguating and filtering references to places in texts for geographic information retrieval (GIR) and related applications. The resulting ontological gazetteer, named LoG (Linked OntoGazetteer), is accessible through Web services by applications and research initiatives on GIR, text processing, named entity recognition and others. The gazetteer currently contains over 13 million places, 140 million attributes and relationships, and 4.5 million non‐geographic entities. Data sources include GeoNames, Freebase, DBPedia and LinkedGeoData, which is based on OpenStreetMap data. An analysis on how these datasets overlap and complement one another is also presented.  相似文献   

Species richness of the genus Molgolaimus (Nematoda) from local to ocean scale along continental slopes     

Gustavo Fonseca  Agnes W. Muthumbi  & Ann Vanreusel 《Marine Ecology》2007,28(4):446-459

This study investigated the distribution of Molgolaimus species (Nematoda) at different hierarchical spatial scales and observed the turnover of species along bathymetrical transects and among transects in two separate geographical regions. Samples from six transects (200–2000 m) from the Southern Oceans (SO) and four bathymetric transects (50–2000 m) from the Western Indian Ocean (WIO) were compared. Of the 30 species recorded, only one was common to both regions. WIO had higher local species richness than the SO. In both regions, the local scale was the greatest contributor to the total species richness. In the SO, there was no difference between species turnover at the different spatial scales, however, in the WIO, the turnover along bathymetrical transects was higher than among separated transects. For the particular genus studied, the evidence suggests that the study area in WIO has more widespread species and was better sampled, while the SO has many restricted species and it is most probably characterized by different biogeographical provinces. At the ocean scale (i.e. WIO versus SO), evolutionary histories may have strongly influenced nematodes species composition, while at local and regional scales, ecological processes are probably promoting species co‐existence and speciation. The high co‐existence of certain species at local scale is partially explained by species preference for different sediment layers.  相似文献   

A preliminary evaluation of wave attenuation by four species of seagrass   总被引：1，自引：0，他引：1  

Mark S. Fonseca  Jennifer A. Cahalan   《Estuarine, Coastal and Shelf Science》1992,35(6)

  相似文献   

From Geo-Pragmatics to Derivation Ontologies: New Directions for the GeoSpatial Semantic Web     

Frederico Fonseca  rea Rodriguez 《Transactions in GIS》2007,11(3):313-316

  相似文献   

Soil geochemical prospecting for gold at Marrancos (Northern Portugual)     

A. P. Reis  A. J. Sousa  E. Cardoso Fonseca 《Journal of Geochemical Exploration》2001,73(1)

This paper discusses some geochemical mapping techniques and their effectiveness in detecting of gold and its pathfinder's geochemical anomalies. The study area (Marrancos area) is situated in Northern Portugal. Gold occurs in a quartz breccia with pyrite and arsenopyrite hosted by metamorphic rocks (hornfels) and it is present in these two sulphide minerals as inclusions or disseminated in the crystal lattice. In this area, the geochemical anomalies obtained by isoconcentration mapping of single elements were difficult to interpret. The use of alternative geochemical mapping such as multielement halos (additive halos) proved to be effective in the definition of Au, As, Bi, Sb, Te and Se secondary geochemical signature.  相似文献   

Geochemical signatures and mechanisms of trace elements dispersion in the area of the Vale das Gatas mine (Northern Portugal)   总被引：2，自引：1，他引：2  

P. Freire vila  J.M. Santos Oliveira  E. Ferreira da Silva  E. Cardoso Fonseca 《Journal of Geochemical Exploration》2005,85(1):17-29

A geochemical survey involving the collection and analysis of 170 stream sediment samples was carried out in Vale das Gatas area in order to delineate geochemical signatures and to detect pollution hazards due to mining.Factor analysis applied to the data showed that the most important variables accounting for the first factor are Ag, Pb, Bi, As, W, Cd, Zn and Cu. These variables represent the most significant metalliferous elements of the original paragenesis, which still maintain a close relationship in the secondary geological environment. The spatial distribution of the factor scores referred to factor 1 indicates that positive scores occur predominantly in the Vale das Gatas and Sabrosa streams and in the main Pinhão river. The results also show that the Vale das Gatas mine is the most important contamination source in the Vale das Gatas district.In order to study the dispersion, transfer and uptake mechanisms of trace elements from the Vale das Gatas mine, additional sample media were collected, i.e., stream sediments, tailings, coatings, waters (surficial and mine waters) and specific biological species. Four sample stations were selected, namely two in connection with abandoned adits of the Vale das Gatas mine, one located in the Vale das Gatas stream and one located in the Pinhão River. The results show that chemical reactions of leaching and precipitation took place controlling the heavy metals in areas near the Vale das Gatas mine.At the same time, positive anomalous patterns are visible along the Pinhão river for about 20 km. The mineralogical composition of the stream sediments suggests that processes of mechanical dispersion also interfere in the secondary distribution of the metalliferous elements in that media.  相似文献