Monitoring Coastal Morphological Changes
517
(i) point measurement of changes in the foredune/backshore line used as a coastline
marker in particular locations
(ii) measurement of surface changes in the foredune either on the seaward face
(marine erosion) or on the landward face (inland migration)
(iii) temporal changes of foredune volume, DTM construction and evaluation of
sediment budget.
(iv) spatial changes of volume, relocation, etc. shown by chart differencing analysis
i.e. overlay
Annual rates will be calculated for all these measurements and the result will be
presented as maps to facilitate international comparison. Additionally the results will
be used to produce animations to allow a fuller understanding of the patterns of
change.
Sources and Methodology
The diversity of the sources of information used to meet these objectives and the need
for integrated data processing makes the use of a GIS virtually essential even though
some data require pre- or post-processing before integration into the GIS. For our study
area the sources and techniques used were:
Cartography: although cartography at 1:1000 is rare in non-urbanized coastal
areas, we have found two reference documents with a 1m. contour interval which
have provided a planimetric and geometric basis for the GIS
1
.
i) a topographic map at 1:1000 from the Ministry of Public Works used
for the application of the Coastal Law of 1989. The map is based on field
survey by classical topographic instrumentation and it was provided in
analogue format. The map was digitzed and integrated into the GIS for
subsequent analysis.
ii) a topographic map 1:1000 from the new Andalusian Cartographic
Institute produced by stereoplotting from air photographs and supplied in
digital format.
1 Projection is UTM, co-ordinates UTM zone 29