Diferenças

Aqui você vê as diferenças entre duas revisões dessa página.

--- geopro:pedro:giscience [2009/02/02 20:01] – pedro
+++ geopro:pedro:giscience [2009/02/17 03:19] (atual) – pedro
@@ Linha 49: / Linha 49: @@
 The framework is independend of the existence of a distance function.
@@ Linha 79: / Linha 81: @@
 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.
+\\