494
C. Johnston and A. Davison
Where there were known to be sublittoral cliffs along the eastern edges of Loch Duich,
with deep soft sediment on the seabed below, the interpolated acoustic data close to the
shoreline were misleading. The acoustic system, because it was directed vertically
downwards from the sea surface, could not detect the cliffs, and showed only the soft
sediment adjacent to them. This was felt to be misleading when represented on the
maps, therefore a blanked-out buffer zone of 50m width was applied to the maps
within the GIS along the whole coastline of Lochs Duich and Alsh. This method was
thought valid as acoustic data were not obtained consistently very close to the shoreline
during the survey. This was not, however, implemented for the Loch Long data,
because acoustic data were obtained close to the shore in this case, and as the loch is so
narrow, this procedure would remove all data for some narrow stretches of the Loch.
C. Johnston and A. Davison
Where there were known to be sublittoral cliffs along the eastern edges of Loch Duich,
with deep soft sediment on the seabed below, the interpolated acoustic data close to the
shoreline were misleading. The acoustic system, because it was directed vertically
downwards from the sea surface, could not detect the cliffs, and showed only the soft
sediment adjacent to them. This was felt to be misleading when represented on the
maps, therefore a blanked-out buffer zone of 50m width was applied to the maps
within the GIS along the whole coastline of Lochs Duich and Alsh. This method was
thought valid as acoustic data were not obtained consistently very close to the shoreline
during the survey. This was not, however, implemented for the Loch Long data,
because acoustic data were obtained close to the shore in this case, and as the loch is so
narrow, this procedure would remove all data for some narrow stretches of the Loch.