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--- geopro:mario:gisdatamodels [2008/11/03 22:49] – mario
+++ geopro:mario:gisdatamodels [2008/11/03 23:49] (atual) – mario
@@ Linha 28: / Linha 28: @@
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 ==== Towards a General Field Model and its Order in GIS  ====
+| LIU, Y., GOODCHILD, M.F., GUO, Q., TIAN, Y. and WU, L., 2008, Towards a General Field model and its order in GIS. International Journal of Geographic Information Science, 22, pp. 623–643 |
 **Abstract:**
 Geospatial data modelling is dominated by the distinction between continuousfield and discrete-object conceptualizations. However, the boundary between them is not always clear, and the field view is more fundamental in some respects than the object view. By viewing a set of objects as an object field and unifying it with conventional field models, a new concept, the General Field (G-Field) model, is proposed. In this paper, the properties of G-Field models, including domain, range, and categorization, are discussed. As a summary, a descriptive framework for G-Field models is proposed. Then, some common geospatial operations in geographic information systems are reconsidered from the G-Field perspective. The geospatial operations are classified into order-increasing operations and non-order-increasing operations, depending on changes induced in the G-Field’s order. Generally, the order can be viewed as an indicator of the level of information extraction of geospatial data. It is thus possible to integrate the concept of order with a geo-workflow management system to support geographic semantics.
+**Resumo:**
+A partir da unificação dos conceitos de geo-campos e geo-objetos, o artigo propõe um novo conceito: //General Field (G-Field) //. Um framework para os modelos //G-Field// também é proposto, sendo que enfoca também conceitos de implementação. Goodchild argumenta que todas as informações geográficas podem ser decompostas em conjuntos de pontos ou geo-átomos.
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 ==== Large-Scale Earth Science Services – A case for Databases ====
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 **Abstract:**
 Earth sciences are about to follow the mapping domain where raster data increasingly get integrated in online services, contribute by far the largest volume. Interestingly, although more and more raster services are getting online, there is few work on a comprehensive model of raster services, rather architectures are of ad-hoc style and optimized towards very narrow applications, such as fast zoom and pan on seamless maps. We claim that databases introduce a new quality of service on high-volume multi-dimensional earth science raster data, characterized by clear and understandable concepts, extensibility, and scalability. To support this, we present a comprehensive conceptual model for raster data in earth science and discuss how an efficient architecture can be derived from it, which is implemented in the rasdaman system. Further, we show how such concepts play a role in the development of OGC's geo raster services, WCS and WCPS. Finally, we discuss some research challenges.
+**Resumo:**
+Propõe um modelo conceitual para dados Raster. Discute como uma arquitetura eficiente pode ser derivada a partir deste modelo. Implementado no sistema Rasdaman, o modelo possui algumas características importantes:
+  * Baseado em arrays n-dimensionais, podendo ter qualquer dimensão, qualquer extensão e qualquer tipo de célula;
+  * Permite particionamento em blocos, não necessariamente regulares. Usa índices geo para rapidamente determinar os blocos consultados;
+  * Opcionalmente, blocos e também resultados de consultas podem ser comprimidos;
+  * Oferece paralelismo entre consultas e estudos pretendem aplicar o paralelismo dentro de uma mesma consulta.
+Propõe também uma extensão do modelo WCS (Web Coverage Service), permitindo análise e navegação não-trivial em Rasters de larga-escala, bem como outras melhorias.