AUTOMATED DIGITAL TERRAIN MODELLING OF COASTAL ZONES
Martin J. Smith and David A. Waldram
Institute of Engineering Surveying and Space Geodesy
University of Nottingham
University Park
Nottingham
NG7 2RD
United Kingdom
Commission IV, Working Group 4
KEY WORDS: Coast, Geology, Surveying, Modelling, DEM/DTM, Softcopy, Digital Photogrammetry
ABSTRACT
Coastal geomorphology is the study of coastal landforms, their evolution, the processes at work on them and the
changes now taking place. The coastal zone is a constantly changing environment. An awareness of the issues
associated within the coastal zone and the need to deal with them in an integrated way, are becoming more prominent
in coastal studies. The need for research into coastal processes is now widely recognised and photogrammetry can be
used for the recording and interpreting of coastal change.
The process of gradual evolution from analogue to digital photogrammetry has brought about many changes in terms
of the characteristics of photogrammetry, more notably the conversion to softcopy photogrammetry. This change
brings about many potential benefits, such as improvements in accuracy, flexibility, more efficient processing and
eventually a reduction in cost.
The Land-Ocean Interaction Study (LOIS) project has been implemented by the Natural Environment Research Council
(NERC). The broad aim of LOIS is to gain an understanding of, and the ability to predict the nature of environmental
changes in the coastal zone of the UK. The Coastal Geology Group at the British Geological Survey (BGS) are
seeking ways of terrain modelling the coastal environment. One of the main objectives is to establish the history of
coastal sedimentation.
The general aim of this research is to develop techniques using digital photogrammetry to survey and model the
coastal zone in order to assess both cliff erosion and sediment movement along the beach. Repeated, detailed cliff
profile surveys are time consuming and individual profile erosion rates have, in the past, been generalised to represent
the erosion rate along entire coastlines. Digital terrain modelling of the coastal environment using new digital
photogrammetric techniques, may offer an efficient method of quantifying sediment yield. This paper present results
from some of the research presently being undertaken.
1. INTRODUCTION the North Sea towards Northern Europe. The area is well
known for the very rapid rate of erosion of its cliffs
The Land-Ocean Interaction Study (LOIS) is one of the — (Pringle 1981). They are composed of boulder clay and
largest and most ambitious projects implemented by the silts, which upon cliff erosion are taken up into
Natural Environment Research Council (NERC). The suspension by the waves, and along with sands and
broad aim of LOIS is to gain an understanding of, and gravels provide the main source of beach material. An
the ability to predict the nature of environmental changes — appreciation of the changes in cliff and beach
in the coastal zone of the UK. The Coastal Geology morphology are fundamental in understanding the very
Group at the BGS are involved with the NERC LOIS rapid erosion of this coastline.
project and are seeking ways of modelling the coastal
environment and its geology. One of the main objectives Many problems in coastal geomorphology require long
is to establish a history of coastal sedimentation. This ^ term investigation continuing over several years, with
data could then be integrated with the geological data for ^ repeated surveys of landforms to identify and measure
analysis of erosion rates and material movement along changes and relate these to correlative studies of
the beach. This is expected to be undertaken in a processes. Perhaps the most sensitive mechanism of
computer aided modelling system, so any models of the the coastline are along the beaches. They react rapidly
coastal area need to be in a form suitable for inclusion in to changes in sediment type or its supply rate. Beach
such a system. morphology is not an isolated system, a change in one
area will be transmitted down the shore line to a whole
The Holderness coast lies on the eastern side of the UK succession of beaches.
between Bridlington and Spurn Head facing East across
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International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996