Diferenças

Aqui você vê as diferenças entre duas revisões dessa página.

--- geopro:pedro:giscience [2009/01/30 16:18] – created pedro
+++ geopro:pedro:giscience [2009/02/17 03:19] (atual) – pedro
@@ Linha 1: / Linha 1: @@
 ====== GIScience ======
+====Concepts and paradigms in spatial information: Are current geographic information systems truly generic?====
+|P. A. Burrough and A. U. Frank, 1994| IJGIS|
+\\
+**Abstract.** This article considers the philosophical and experiential foundations of human
+perception of geographical phenomena and their abstraction and coding in geographical
+information systems. It examines the role of culture and language in describing geographical
+reality and explores the ways geographical data models reflect how people view the world.
+Differences between those who see the world as made of exact entities and smooth continuous
+surfaces, and those who prefer to view reality as a dynamic and complex are explored in terms of
+five aspects of spatial data, namely (i) objects versus fields, (ii) single scale versus multiple scales,
+(iii) Boolean versus multivalued logic, (iv) static versus dynamic descriptions and (v) determinism
+versus uncertainty. These five aspects are further divided into nine factors of geographical data
+which indicate the differences in the way people perceive spatial data. Eight "typical" GIS
+applications and four generic methods of handling spatial data are examined in terms of these nine
+factors to define a GIS "hyperspace". The locations of the typical applications and the generic
+methods in this hyperspace show why no single generic approach to spatial data handling is
+sufficient for all possible applications. The analysis reinforces the authors' contention that spatial
+data analysis tools need to be chosen and developed to match the way users perceive their domains:
+these tools should not impose alien thought modes on users just because they are impressively
+"high tech". The implications of this conclusion for choosing or developing spatial information
+systems, for data standardization and generalisation and for the further development of "GIS" as a
+discipline in its own right are presented as topics for further discussion.
+\\
+====Point-set topological spatial relations====
+|M. J. Egenhofer and R. D. Franzosa, 1991| IJGIS|
+\\
+**Abstract:** Practical needs in the realm of Geographic Information Systems (GIS) have driven
+the efforts to investigate formal and sound methods to describe spatial relations. After an
+introduction of the basic ideas and notions of topology, a novel theory of topological relations
+between sets is developed in which **the relations are defined in terms of the intersections of
+the boundaries and interiors of two sets**. By considering empty and non-empty as the values of the
+intersections, a total of sixteen topological spatial relations are described, each of which can be
+realized in RxR. This set is reduced to nine relations if the sets are restricted to spatial regions,
+a fairly broad class of subsets of a connected topological space having application to GIS. It is
+shown that these relations correspond to some of the standard set-theoretic and topological spatial
+relations between sets such as equality, disjointness, and containment in the interior.
+\\
+The framework is independend of the existence of a distance function.
+====Progress in Computational Methods for Representing Geographic Concepts====
+|M. J. Egenhofer and J. Glasgow and O. Gunther and J. R. Herring and D. J. Peuquet, 1999| IJGIS|
+\\
+**Abstract:** Over the last ten years, a subfield of GIScience has been recognized that addresses the linkage
+between human thought regarding geographic space and the mechanisms of implementing these in computational
+models. This research area has developed an identity through a series of successful international conferences and
+the establishment of a journal. It has also been complemented through community activities such as an international
+standardization efforts and GIS interoperability. Historically, much of the advancement in computational methods has
+occurred at - or close to - the implementation level, as exemplified by the attention on the development of spatial access
+methods. Significant progress has been made at the levels of spatial data models and spatial query languages, although we
+note the lack of a comprehensive theoretical framework comparable to the relational data model in database management
+systems. The difficult problems that need future research efforts are the highly abstract level of capturing semantics of
+geographic information. A cognitive motivation is most promising as it shapes the focus on the user's needs and points of
+view, rather than on efficiency as in the case of a bottom-up system design. We also identify the need for new research in
+fields, models of qualitative spatial information, temporal aspects, knowledge discovery, and the integration of GIS with
+database management systems.
+\\
+A spatial join takes two sets of spatial objects as input and produces a set of pairs of spatial objects as output, such that
+each pair fulfils the given spatial predicate. Examples include, "Find all houses that are less than 10Km from a lake" or
+"Find all buildings that are located within a wetland."
+Early proposals for multidimensional data structures, such as k-d tree or quadtrees, focused on memory-resident data and,
+therefore, do not take secondary storage management explicitly into account.
+The focus of GIS has to rely on cognitive considerations, rather than making small increments to established algorithms
+and data structures.
+====Why not SQL!====
+|M. J. Egenhofer, 1992| IJGIS|
+\\
+**Abstract:** The application of traditional database query languages, primarily the SQL, for GIS and other non-standard
+database applications has been tried unsuccessfully, therefore, several extensions to the relational SQL have been proposed
+to serve as a spatial query language. It is argued that the SQL framework is inappropriate for an interactive query language
+for GIS and an extended SQL is at best a short term solution. Any spatial SQL dialect has a number of serious deficiencies,
+particularly the patches to incorporate the necessary spatial concepts into SQL.
+\\
+A criterion for evaluating the suitability of a query language for a non-standard application domain is: "How useful are the
+database operations provided by the query language for the particular application?"
+====Higher Order Functions Necessary for Spatial Theory Development====
+|A. U. Frank, 1997| Proceedings of Auto-Carto 13|
+\\
+**Abstract:**The tool we use influences the product. This paper demonstrates that higher
+order functions are a necessary tool for research in the GIS area, because higher
+order functions permit to separate the treatment of attribute data from the
+organisation of processing in data structures. Higher order functions are
+functions which have functions as arguments. A function to traverse a data
+structure can thus have as an argument a function to perform specific
+operations with the attribute data stored. This is crucial in the GIS arena, where
+complex spatial data structures are necessary. Higher order functions were
+tacitly assumed for Tomlin’s Map Algebra.
+The lack of higher order functions in the design stage of GIS and in the
+implementation is currently most felt for visualization, where the problems of
+the interaction between the generic computer graphics solutions and the
+particulars of the application area preclude advanced solutions, which combine
+the best results from both worlds. Similar problems are to be expected with the
+use of OpenGIS standardized functionality.
+This paper demonstrates the concept of higher order functions in a modern
+functional programming language with a class based (object-oriented) type
+concept. It shows how the processing of data elements is completely separated
+from the processing of the data structure. Code for different implementations of
+data structures can be freely combined with code for different types of
+representation of spatial properties in cells. The code fragments in the paper are
+executable code in the Gofer/Haskell functional programming language.
+\\
+In C++ a special ‘iterator’
+concept is provided (but tricky to use) to save the programmer the difficulties
+with passing functions as parameters. The programming languages used for
+implementation are based on variables and statements and functions remain
+second class citizens.
+**higher order functions allow to separate the part of
+operations specific to the data structure from the code of the operations which
+is specific to the data type stored. GIS are large data collections and must use
+complex spatial data structures. It is beneficial to separate the code which
+traverses the data structure from the code which operates on the feature data.**
+====Fiat and Bona Fide Boundaries====
+|B. Smith and A. C. Varzi, ????| Philosophy and Phenomenological Research|
+\\
+**Abstract:** We argue that the basic typology of spatial boundaries involves an opposition
+between bona fide (or physical) boundaries on the one hand,
+and fiat boundaries on the other, the latter being exemplified especially
+by boundaries induced through human demarcation, for example
+in the geographic realm. The classical metaphysical problems connected
+with the notions of adjacency, contact, separation and division
+can be resolved in an intuitive way by recognizing this two -sorted ontology
+of boundaries. Bona fide boundaries yield a notion of contact
+that is effectively modeled by classical topology; the analogue of contact
+involving fiat boundaries calls, however, for a different account,
+based on the intuition that fiat boundaries do not support the
+open/closed distinction on which classical topology is based. In the
+presence of this two -sorted ontology it then transpires that mereotopology—
+topology erected on a mereological basis—is more than a
+trivial formal variant of classical point-set topology.
+\\