David M. Mark

The extraction of drainage networks from digital elevation data

The extraction of drainage networks from digital elevation data is important for quantitative studies in geomorphology and hydrology. A method is presented for extracting drainage networks from gridded elevation data. The method handles artificial pits introduced by data collection systems and extracts only the major drainage paths. Its performance appears to be consistent with the visual interpretation of drainage patterns from elevation contours.

Analysis of Axial Orientation Data, Including Till Fabrics

An error in the significance test associated with a rotational vector procedure for analysis of axial orientation data is pointed out and explained. An alternative approach already well established in the geologic literature, which does not require that sense be assigned to the axial data, is discussed; the results of the application of both methods to 36 till fabrics are compared. It is concluded that the alternative approach is superior because it is statistically sound and more efficient with regard to computer time required; it also provides more information about the fabric than does the rotational vector procedure.

Spatial Information Theory. Cognitive and Computational Foundations of Geographic Information Science

Landmarks and Navigation.- Large-Scale Navigation: The Insect Case.- Route Navigation Using Motion Analysis.- The Nature of Landmarks for Real and Electronic Spaces.- Route Directions.- Pictorial and Verbal Tools for Conveying Routes.- Elements of Good Route Directions in Familiar and Unfamiliar Environments.- The Production of Route Instructions in Underground and Urban Environments.- Abstraction and Spatial Hierarchies.- One Step up the Abstraction Ladder: Combining Algebras - From Functional Pieces to a Whole.- Formalizing Regions in the Spatial Semantic Hierarchy: an AH-Graphs implementation approach.- Abstraction, Levels of Detail, and Hierarchies in Map Series.- Topological Relations in Hierarchical Partitions.- Spatial Reasoning Calculi.- A Predication Calculus for Qualitative Spatial Representations.- Simple Models for Simple Calculi.- Terminological Default Reasoning about Spatial Information: A First Step.- Reasoning about Cardinal Directions Using Grids as Qualitative Geographic Coordinates.- Ontology of Space.- The Role of Identity Conditions in Ontology Design.- Atomicity vs. Infinite Divisibility of Space.- The Mereotopology of Discrete Space.- Agglomerations.- Ontology and Geographic Objects: An Empirical Study of Cognitive Categorization.- Modes of Connection.- Visual Representation and Reasoning.- Representation and Reasoning about Shapes: Cognitive and Computational Studies in Visual Reasoning in Design.- An Algebraic Interpretation of Semantic Networks.- Data Characterization Schema for Intelligent Support in Visual Data Analysis.- Maps and Routes.- Recognition-Triggered Response and the View-Graph Approach to Spatial Cognition.- A Formal Model of the Process of Wayfinding in Built Environments.- A Spatial Model Based on the Notions of Spatial Conceptual Map and of Objects Influence Areas.- Granularity and Qualitative Abstraction.- Granulation for Graphs.- On Ontology and Epistemology of Rough Location.- Qualitative Spatial Representation for Situational Awareness and Spatial Decision Support.- Qualitative Motion Representation in Egocentric and Allocentric Frames of Reference.

Do Mountains Exist? Towards an Ontology of Landforms

The authors begin the paper with the question ‘Do mountains exist?’ They show that providing an answer to this question is surprisingly difficult and that the answer that one gives depends on the context in which the question is posed. Mountains clearly exist as real correlates of everyday human thought and action, and they form the archetype for geographic objects. Yet individual mountains lack many of the properties that characterize bona fide objects, and ‘mountains’ as a category also lacks many of the properties that characterize natural kinds. In the context of scientific modeling of the environment, especially of such phenomena as surface hydrology and fluvial erosion and deposition, mountains are not picked out as constituents of reality in their own right at all; rather, they are just parts of the field of elevations whose gradients shape the direction of runoff and influence the intensity of erosion. Thus, although an object-based ontology of mountains and other landforms is required to do justice to our everyday conceptions of the environment and to support spatial reasoning and natural language processing, topographic databases designed to support environmental modeling can be field-based at geographic scales.

Cognitive models of geographical space

This paper reviews research in geographical cognition that provides part of the theoretical foundation of geographical information science. Freestanding research streams in cognitive science, behavioural geography, and cartography converged in the last decade or so with work on theoretical foundations for geographical information systems to produce a coherent research community that advances geographical information science, geographical information systems, and the contributing fields and disciplines. Then, we review three high-priority research areas that are the topics for research initiatives within the NCGIAs Project Varenius. Other topics consider but ranked less important at this time are also reviewed.

On the misuse of regression in earth science

Simple least-squares regression analysis is applied to almost all empirical curve-fitting problems in earth science (and related fields). Its use, however, should be restricted to predictive situations. For comparisons with theory or among fitted lines, the related technique termed functional analysisshould be employed. To apply this method, the ratio of the random components of the variances of the variables must be estimated. Principles are illustrated with examples from geomorphometry, especially the stream frequency-drainage density relation.

On size and scale in geomorphology

Progress in scientific understanding is made by either deductive or inductive reasoning. The former leads to necessary statements embodied in theories: the latter expresses formal relations (i.e. relations that are not analytically rigorous) amongst phenomena that have been observed empirically. The rational elegance of textbooks notwithstanding, most inquiries, at least in the field sciences, are initially prompted by the observation of formal relations. Such relations commonly reveal correlations amongst geometric or functional aspects of systems of interest. An important approach in contemporary geomorphology is to seek empirical ’equilibrium’ relations amongst landform parameters, or between landform parameters and supposed governing processes. It is the purpose of this paper to examine some of these formal relations in terms of the information that they indicate must be included in geomorphological theories, and the constraints imposed by the requirements of sound mechanical theories.

Geomorphometric Parameters: A Review and Evaluation

AbstractAll aspects of surface form can be considered to reflect surface roughness. Horizontal variation includes the concepts of texture and grain, while vertical variation is discussed under reli...

Cognitive Aspects of Human-Computer Interaction for Geographic Information Systems

Keywords: Human-Computer Interaction (HCI) ; GIS ; cognition Reference Record created on 2005-06-20, modified on 2016-08-08

Modelling conceptual neighbourhoods of topological line-region relations

Abstract Based on the 9-intersection for binary topological relations, two models of conceptual neighbourhoods among topological relations between a line and a region are developed. The snapshot model derives the neighbourhoods by comparing pairs of topological relations and selects neighbours based on least noticeable differences, whereas the smooth-transition model develops neighbourhoods based on the knowledge of the deformations that may change a topological relation. The resulting similarity diagrams show some differences, which were compared with the results from tests in which human subjects were asked to organized line-region relations into groups of similar relations. The groupings the subjects made indicate that the smooth-transition model captures more important aspects of the similarity of topological line-region relations than the snapshot model.