Author(s)

G.A. ACHILLEOS

Abstract

The existence of elevation errors in Digital Elevation Models (DEMs) is usually ignored during spatial analysis of problems concerning planning through a sustainable sense of development. Examples of such analyses are: slope analysis for site selection, designing infrastructure works on physical terrains, 3D calculations on a basic surface like the terrain, sitting and zoning definition through elevation, etc. As a result, conclusions are extracted, decisions are made and actions are designed and executed, while the problem is examined theoretically, away from reality. This article describes the attempt to introduce a new model, the Digital Elevation Error Model, which incorporates elevation uncertainty and fuzziness, and accompanies a DEM, uniquely. The use of uncertain terrains combined with a probabilistic soft-decision theory, eliminates the risk of taking decisions that do not apply to the real problem under examination. The research on this subject has shown deviations from the results, from those of a hard-decision theory, up to 20–50% for volume measurements, area measurements, definition of boundaries, visibility calculations, etc. The absence of an integrated geographic information system, able to manage data uncertainty, makes it necessary to use alternative approaches to the problem but not the appropriate and scientific ones.

Keywords

coastal zone, Digital Elevation Models, elevation errors, uncertain volume calculation, uncertainty, visibility analysis