The concept of Open GIS depends on precise definitions of data, operations and interfaces. This paper argues for the use of functional programming languages as specification and prototyping tools for Open GIS components. It shows how functional programming languages fulfill the key requirements for formal specification languages and allow for rapid prototyping in addition. So far, it has never been possible to integrate specification and prototyping in a single, easy to use environment. Most existing specification methods lack appropriate tools for checking and prototyping, while existing tools lack either sound semantics or usability or both. The paper discusses the role of specifications in GIS, requirements for specification languages, and a survey of algebraic specifications as well as of functional languages. It then describes how functional languages can be used for writing and executing algebraic specifications. A brief example of a GIS data type specification in a functional la...

Integration of geographic information has increased in importance because of new possibilities arising from the interconnected world and the increasing availability of geographic information. Ontologies support the creation of conceptual models and help with information integration. In this paper, we propose a way to link the formal representation of semantics (i.e., ontologies) to conceptual schemas describing information stored in databases. The main result is a formal framework that explains a mapping between a spatial ontology and a geographic conceptual schema. The mapping of ontologies to conceptual schemas is made using three different levels of abstraction: formal, domain, and application levels. At the formal level, highly abstract concepts are used to express the schema and the ontologies. At the domain level, the schema is regarded as an instance of a generic data model. At the application level, we focus on the particular case of geographic applications. We also discuss the in¯uence of ontologies in both the traditional and geographic systems development methodologies, with an emphasis on the conceptual design phase. Keywords: systems ontologies, geographic conceptual models, geographic data modeling, geographic information 1.

Guarino for their prompt responses to my questions. Third, to all my colleagues and friends in the Department of Spatial Information Science I would like to thank you for sharing the good and bad moments of my study life. I feel fortunate for having being part of a friendly environment that made my Ph.D. program an enjoyable and unforgettable experience. iii Fourth, I thank the support and funding from the University of Concepcin, Chile, and the initial funding from the Fulbright foundation. Further funding from the National Center of Geographic Information and Analysis, the National Imagery and Mapping Agency, and Lockheed Martin are gratefully acknowledged. Most important, I thank the continuous support, love, and patience of Christian and Alicia. This long journey would not have been possible without them. iv Table of Contents Acknowledgments .......................................................................................................ii List of Figu

The need to share and integrate spatial data has spurred an interest in metadata. This paper documents the acquisition and modeling of metadata from eleven digital geodata sources in Austria. It shows how the information was modeled according to the proposed CEN standard on metadata, how it was encoded in a database, and what problems were encountered during these processes. The paper concludes with a discussion of recent developments around metadata and of the option to make meta-databases available on the world-wide web.

Interoperability is a crucial problem for geographic information systems. The transfer of data and models between different systems requires the ability to set up a correspondence between concepts in one system to concepts in the other. Concept matching is helped by ontologies. However, the challenge of making ontologies themselves interoperable continues. In other words, given two geo-ontologies, the basic question is: to which degree are these two geo-ontologies interoperable? In this paper, we consider that a geo-ontology describes things that can be assigned to locations on the surface of the Earth and relations between these things. A geo-ontology has concepts that correspond to physical and social phenomena in the real world. We suggest a classification of these concepts based on their use for describing geo-objects. We present a basic set of concepts for a geographical ontology, based on descriptions of the physical world and of the social reality. We also present a framework for measuring the degree of interoperability between geo-ontologies. We consider that this problem is a special case of Bernstein’s model management algebra for metadata descriptions. We propose to use a matching operator for measuring

Formal specifications are difficult to read.Executable specifications allow to see the behavior of the specified objects and help the domain specialist to detect errors quickly. We present here a method which allows to write axiomatic specifications which can be executed and discuss the limitations in expressive power imposed by the restriction to constructive axioms and how it can be circumvented. The method results from practical efforts to formalize the meaning of object types for Geographic Information Systems. If such data are shared betweenorganisations, differences in the semantics become apparent and formal methods for their definition become necessary. Most formal methods are based on first order languages. Software engineering often uses algebraic methods, but tools practically used for data exchange standard definitions are restricted to signatures and do not capture the behavior of the operations. We present here an algebraic approach using a functional programming language...

The formal specification of spatial objects and spatial relations is at the core of geographic data exchange and interoperability for geographic information systems (GIS). It is necessary that the representation of such objects and relations comes close to how people use them in their everyday lives, i.e., that these specifications are built upon elements of human spatial cognition. Image schemata have been suggested as highly abstract and structured mental patterns to capture spatial and similar physical as well as metaphorical relations between objects in the experiential world. We assume that image-schematic details for large-scale (geographic) space are potentially different from image-schematic details for small-scale (table-top) space. This paper reviews methods for the formal description of spatial relations, integrates them in a categorical view, and applies the methods arrived at to formally specify image schemata for large-scale (LOCATION, PATH, REGION, and BOUNDARY) as well ...

This paper presents a practical application of context for the evaluation of semantic similarity. The work is based on a new model for the assessment of semantic similarity among entity classes that satisfies cognitive properties of similarity and integrates contextual information. The semantic similarity model represents entity classes by their semantic relations (is-a and part-whole) and their distinguishing features (parts, functions, and attributes). Context describes the domain of an application that is determined by the user's intended operations. Contextual information is specified by a set of tuples over operations associated with their respective entity-class arguments. Based on the contextual information, a partial word-sense disambiguation can be achieved and the relevance of distinguishing features for the similarity assessment is calculated in terms of the features' contribution to the characterization of the application domain.

A number of attempts have been made to provide standard terms or definitions for real world entities to aid in data sharing. However, the information communities model of the OpenGIS Consortium recognizes that individual user groups will have their own set of definitions and language, and that translations between these will be necessary (OpenGIS Consortium, 1996). In order for translations to be successful, a method for capturing the semantics of database elements is required. Simple definitions have been shown to be inadequate (Mark, 1993; Kuhn, 1994). An alternative method for the representation of element semantics uses inclusion rules, and is based on psychological theory of concept attainment, and particularly on a model proposed by Klausmeier, Ghatala and Frayer (1974). The method identifies inclusion rules as being the basis for concept attainment, and combines these rules into predicates to represent element semantics. The method allows cross referencing between predicates that define element semantics, so reduces reliance on the expression style of individual participants in the data sharing activity. In addition to providing a method for representation of element semantics, the inclusion rules method allows the relationships between element semantics to be determined. This determination is necessary in order for semantic translation to occur. An example using topographic elements indicates that rules can be defined and predicates formed to represent element semantics with limited dependence on individual expression. The example then shows that predicates can be used to translate element semantics to allow data sharing between heterogeneous communities.

Abstract: GIS eased into geography without much discord until the 1990s, when a flurry of commentaries about the relative merits of GIS made their way into a number of geographic journals. The ensuing decade was marked by varying degrees of friction between GIS practitioners and their critics in human geography. Despite the methodological chasm between the two groups, little discussion of the implications of these differences has ensued. This article fills that gap with a historiographic examination of critiques of GIS. Critiques of GIS are organized into three waves or periods, each characterized by distinct arguments. The first wave, from 1990 to 1994, was marked by the intensity of debate as well as an emphasis on positivism. By 1995, the conversation waned as the number of critics grew, while GIS practitioners increasingly declined comment. This second wave marked the initiation of a greater degree of co-operation between GIS scholars and their critics, however. With the inception of the National Center for Geographic Information Analysis (NCGIA) Initiative 19, intended to study the social effects of GIS, many critics began to work closely with their peers in GIS. In the third wave, critiques of GIS expressed a greater commitment to the technology. Throughout the decade, debates about the technology shifted from simple attacks on positivism to incorporating more subtle analyses