Chapter Eight - Digital Mapping: Visualisation, Interpretation and Quantification of Landforms

Abstract

Extensive uptake of geographical information systems (GIS) and techniques for digital processing, along with a proliferation of satellite imagery and digital elevation models (DEMs), has led to a dramatic rise in the use of remote sensing technologies for geomorphological mapping and, specifically, digital mapping. This chapter outlines the rationale for operator-based, manual, mapping and highlights two primary constraints upon the detectability of individual landforms: (i) expertise of an interpreter and (ii) the data source(s) used. An organisational framework is then provided for digital geomorphological mapping within a GIS based upon on-screen digitising of landforms. Such mapping records an abstraction of the underlying data, with landforms digitised as vector features (points, lines and polygons). Methods to best visualise satellite imagery and DEMs are then presented; ‘non-illuminated’ techniques for initial mapping, later augmented by relief shading, are recommended. The final sections review the quantification of landforms (calculations of vector geometry) and potential sources of error (completeness, classification and location).