Andrew U. Frank

Geographic Objects with Indeterminate Boundaries

Current geographical information systems GIS deal almost exclusively with well-defined, static geographical objects ranging from physical landscapes to towns and transport systems. Such objects, exactly located in space, can easily be handled by modern GIS, yet form only a small proportion of all the possible geographical objects.; This book challenges the assumption that the world is compsed of exactly defined and bounded geographic objects such as land parcels, rivers and countries. ignoring the essential complexity of the world, current GIS do not adequately address problems as diverse as the resolution of crime between national boundaries, or the interpretation of views of people from different cultures. This work, bringing together a range of specialists from fields such as linguistics, computer science, land surveying, cartography and soil science, examines current research into the challenges of dealing with geographical phenomena that cannot easily be forced into one of the two current standard data models.

Theories and Methods of Spatio-Temporal Reasoning in Geographic Space

theories and methods of spatio temporal reasoning in geographic space international conference gis from space to territory theories and methods of spatio temporal reasoning pisa italy september 1992 proceedings. Book lovers, when you need a new book to read, find the book here. Never worry not to find what you need. Is the theories and methods of spatio temporal reasoning in geographic space international conference gis from space to territory theories and methods of spatio temporal reasoning pisa italy september 1992 proceedings your needed book now? Thats true; you are really a good reader. This is a perfect book that comes from great author to share with you. The book offers the best experience and lesson to take, not only take, but also learn.

Spatial Infromation Theory - A Theoretical Basis for GIS

An improved document support system for use in a character by character printer of the type that employs a rear striking hammer to drive the document, at the printing position, into contact with a selected symbol on a rotating type font. Typically, the type font would be on the surface of a constantly rotating wheel. In application, a front paper guide is provided which limits and defines the normal spacing between the document and the type font in the area of the printing position; the said spacing normally being quite small. A rear paper guide is supported by the hammer structure and is spring biased towards the front paper guide. Both paper guides include cutouts or openings so that the printing hammer can drive the document towards the selected character of the font to effect a printing action. The paper guides cooperate to maintain the document in a fixed location, relative to the type font, and serve to compress the document pack which may comprise an original document, carbons, and multiple copies, so that there are no separations, or air pockets, therebetween at the printing position. The paper guides enable the production of a more uniform appearing print of improved quality. Supporting and holding the document in a known position allows a constant portion of the kinetic energy of the print hammer to be available for affecting a print action, thus increasing the quality of the print.

Qualitative spatial reasoning about distances and directions in geographic space

Abstract Most known methods for spatial reasoning translate a spatial problem into an analytical formulation in order to solve it quantitatively. This paper describes a method for formal, qualitative reasoning about distances and cardinal directions in geographic space. The problem addressed is how to deduce the distance and direction from point A to C, given the distance and direction from A to B and B to C. We use an algebraic approach, discussing the manipulation of distance and direction symbols (e.g. ‘N’, ‘E’, ‘S’ and ‘W’, or ‘Far’ and ‘Close’) and define two operations, composition and inverse , applied to them. After a review of other approaches, the desirable properties of deduction rules for distance and direction values are analyzed. This includes an algebraic specification of the ‘path’ image schema, from which most of the properties of distance and direction manipulation follow. Specific systems for composition of distance are explored. For directions, a formalization of the well-known triangular concept of directions (here called cone-shaped directions) and an alternative projection-based concept are explored. The algebraic approach leads to the completion of distance or direction symbols with an identity element, standing for the direction or distance from a point to itself. The so completed axiom system allows deductions, at least ‘Euclidean-approximate’, for any combination of input values.

Qualitative spatial reasoning: cardinal directions as an example

ABSTRACT Abstract. Geographers use spatial reasoning extensively in large-scale spaces, i.e., spaces that cannot be seen or understood from a single point of view. Spatial reasoning differentiates several spatial relations, e.g. topological or metric relations, and is typically formalized using a Cartesian coordinate system and vector algebra. This quantitative processing of information is clearly different from the ways human draw conclusions about spatial relations. Formalized qualitative reasoning processes are shown to be a necessary part of Spatial Expert Systems and Geographical Information Systems. Addressing a subset of the total problem, namely reasoning with cardinal directions, a completely qualitative method, without recourse to analytical procedures, is introduced and a method for its formal comparison with quantitative formula is defined. The focus is on the analysis of cardinal directions and their properties. An algebraic method is used to formalize the meaning of directions. The standard ...

Tiers of ontology and consistency constraints in geographical information systems

Consistency constraints placed on a database to assure, that values incorporated in the database are consistent, are a well known foundation of Geographical Information Systems. Unfortunately in real situations rules for consistency constraints are not so clear, and inconsistent ontologies are common place, not least in geographical information, covering as it does a much wider realm than many other information systems I have suggested elsewhere 5-tiers of ontology for GIS. Such an ontology can integrate different ontological approaches in a unified system. In this paper the relation of the 5-tier ontology and consistency constraints is explored, and it is shown that different constraints are appropriate to different tiers.

Qualitative Spatial Reasoning with Cardinal Directions

Following reviews of previous approaches to spatial reasoning, a completely qualitative method for reasoning about cardinal directions, without recourse to analytical procedures, is introduced and a method is presented for a formal comparison with quantitative formulae. We use an algebraic method to formalize the meaning of cardinal directions. The standard directional symbols (N, S, E, W) are extended with a symbol 0 to denote an undecided case, which greatly increases the power of inference. Two examples of systems to determine and reason with cardinal directions are discussed in some detail and results from a prototype are given. The deduction rules for the coordination of directional symbols are formalized as equations; for inclusion in an expert system they can be coded as a look-up table (given in the text). The conclusions offer some direction for future work.

A topological data model for spatial databases

There is a growing demand for engineering applications which need a sophisticated treatment of geometric properties. Implementations of Euclidian geometry, commonly used in current commercial Geographic Information Systems and CAD/CAM, are impeded by the finiteness of computers and their numbering systems. To overcome these deficiencies a spatial data model is proposed which is based upon the mathematical theory of simplices and simplicial complexes from combinatorial topology and introduces completeness of incidence and completeness of inclusion as an extension to the closed world assumption. It guarantees the preservation of topology under affine transformations. This model leads to straightforward algorithms which are described. The implementation as a general spatial framework on top of an object-oriented database management system is discussed.

Concepts and paradigms in spatial information: are current geographical information systems truly generic?

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 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 multi-valued 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 t...

Multiple representations for cartographic objects in a multi-scale tree—An intelligent graphical zoom

Abstract In Geographic Information Systems, a function to draw cartographic sketches quickly and in arbitrary scales is needed. This calls for cartographic generalization, a notoriously difficult problem. Efforts to achieve automatic cartographic generalization were successful for specific aspects, but no complete solution is known, nor are there any expected within the immediate future. In practical applications, a base map is stored and its scale is changed. Without major distortions, only changes to twice or half the original scale are feasible by simple numeric scale change. Everything beyond this requires adaptation of symbols, selection of objects, placements of labels, etc. Extending ideas of hierarchies or pyramids, where representations of the same objects at different scales are stored, a multi-scale, hierarchial spatial model is proposed. Objects with increasing detail are stored in levels and can be used to compose a map at a particular scale. Applied to the particular problem of cartographic mapping, this results in a multi-scale cartographic tree. The same concept can be used equally well for other applications, which require rendering of objects at different levels of detail. The structure of the multi-scale tree is explained. It is based on a trade-off between storage and computation, replacing all steps which are difficult to automate by essentially redundant storage. The dominant operation is ‘zoom,’ which moves towards a more detailed level, intelligently replacing the current graphical representation with the more detailed one, appropriate for the selected new scale. Methods to select objects for rendering are based on the principle of equal information density. Principles of possible implementations are presented.