Multidimensional representation of geographic features
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Multidimensional Representation of Geographic Features. E. Lynn Usery Research Geographer U.S. Geological Survey. Outline. Introduction Objectives Background Approach Theoretical Basis Implementation Strategy Application – DLG-F usage Conclusions. Introduction.

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Multidimensional Representation of Geographic Features

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Multidimensional representation of geographic features

Multidimensional Representation of Geographic Features

E. Lynn Usery

Research Geographer

U.S. Geological Survey

ISPRS Congress 2000


Outline

Outline

  • Introduction

  • Objectives

  • Background

  • Approach

    • Theoretical Basis

    • Implementation Strategy

  • Application – DLG-F usage

  • Conclusions

ISPRS Congress 2000


Introduction

Introduction

  • Need for geoinformation theory

    • UCGIS Research Priority on “Geographic Representation”; proposed theme on ontology.

    • Need to handle 3 dimensions and time

    • Need to interface to geographic process models

      • Climate models

      • Growth models

      • Biologic models

      • Watershed/water quality models

ISPRS Congress 2000


Introduction1

Introduction

  • Geographic reality consists of entities and processes

  • We represent entities as objects and processes as models

    • Mathematical (process)

    • Data driven (map, spatial, or GIS)

    • Combinations

ISPRS Congress 2000


Objectives

Objectives

  • Advance development of theory of geographic information supporting multiple representations.

  • Validate theory in multiple applications.

  • Develop implementation around specific application for feasibility testing.

  • Use current GIScience knowledge as base from which to extend representation ideas.

ISPRS Congress 2000


Background

Background

  • Significant work toward a theory

    • Peuquet, 1988; Molenaar, 1991; Mark, 1993; Usery, 1996; Frank, 1998.

    • Geography

      • Place, attribute, time as fundamental basis for spatial analysis from Berry (1964), basis of current GIS

      • Region theory

    • Cartography

      • Abstraction and generalization concepts

ISPRS Congress 2000


Background1

Background

  • Cognitive psychology

    • Basic level of categorization exists

    • For geography, that level is geographic entities or features

      • Roads

      • Streams

      • Buildings

      • Watersheds

ISPRS Congress 2000


Problems

Problems

  • How to advance theory of geoinformation?

  • Limits of commercial GIS software systems

    • Map model of reality

    • Geometry (raster or vector) based objects with attached attributes

  • Needs to advance

    • ,,Z,t or X,Y,Z,t coordinates for entities

    • Motion and process

ISPRS Congress 2000


Feature approach

Feature Approach

  • Feature is geographic entity and object representation

  • One feature, many objects

    • Multiple resolutions

    • Multiple geometries

    • Access from single identity

ISPRS Congress 2000


Multidimensional representation of geographic features

Definitions

ISPRS Congress 2000


Multidimensional representation of geographic features

ISPRS Congress 2000


Requirements to move from theoretical concepts to implementation

Requirements to Move from Theoretical Concepts to Implementation

  • Theory of sufficient completeness to support application needs

  • Transition framework from theoretical concepts to a data model

  • Implementation methodology from the data model

ISPRS Congress 2000


Theoretical completeness

Theoretical Completeness

  • Components of theory available

    • Feature concepts

    • Human understanding

      • Category theory

      • Metaphor

      • Algebraic formalisms

  • Missing links

    • Feature to feature relations

      • Some work on topological relations

    • Thematic, temporal relations

ISPRS Congress 2000


Transition framework

Transition Framework

  • Dimensions

  • Concepts

  • Data Models

  • Data Structures

ISPRS Congress 2000


Multidimensional representation of geographic features

ISPRS Congress 2000


Implementation methodology

Implementation Methodology

  • Feature processing system

    • Create, select, manipulate, analyze features

    • Use existing databases

      • Spatial, thematic, temporal attributes and relationships

      • Vector geometry (,,Z,t lists)

      • Raster geometry (pixel matrices)

    • Heuristics, procedures, models

ISPRS Congress 2000


Multidimensional representation of geographic features

ISPRS Congress 2000


Application of the framework

Application of the Framework

  • Watershed/water quality modeling application

  • Test site in Little River, Georgia, USA

    • 340 sq. km.

    • Traditional data layers

      • Soils, land cover, elevation, precipitation

    • Derived information

      • Slope, aspect, flow directions, flow paths, flow planes

    • Multiple geometries and resolutions

      • Vector

      • Raster at 3, 30, 60, 120, 210, 240, 480, 960, 1920 m cells

ISPRS Congress 2000


Multidimensional representation of geographic features

ISPRS Congress 2000


Multidimensional representation of geographic features

ISPRS Congress 2000


Multidimensional representation of geographic features

ISPRS Congress 2000


Multidimensional representation of geographic features

ISPRS Congress 2000


Multidimensional representation of geographic features

ISPRS Congress 2000


Multidimensional representation of geographic features

ISPRS Congress 2000


Implementation of watershed features

Implementation of Watershed Features

  • Use USGS DLG-F structures

  • Apply to raster geometry

  • Build attributes and relations specific to defined features

  • Develop parameters for water models

ISPRS Congress 2000


Multidimensional representation of geographic features

ISPRS Congress 2000


Multidimensional representation of geographic features

ISPRS Congress 2000


Multidimensional representation of geographic features

ISPRS Congress 2000


Multidimensional representation of geographic features

ISPRS Congress 2000


Multidimensional representation of geographic features

ISPRS Congress 2000


Multidimensional representation of geographic features

ISPRS Congress 2000


Multidimensional representation of geographic features

ISPRS Congress 2000


Multidimensional representation of geographic features

ISPRS Congress 2000


Multidimensional representation of geographic features

ISPRS Congress 2000


Conclusions

Conclusions

  • Conceptual framework (addition to theory) supporting multiple geometries and multidimensional representation developed.

  • Geographic feature is unique entity;basis of theory

    • Feature has multiple object representations

  • Transition framework from concepts to data model developed

  • Data model to data structure transition developed

ISPRS Congress 2000


Conclusions1

Conclusions

  • Framework being implemented for watershed/water quality modeling

  • Features developed

  • Data structures for features developed from USGS DLG-F and are being implemented against raster geometry.

ISPRS Congress 2000


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