381
Dynamic Segmentation in the Coastal Information System
units which represented barrier beaches. The 'from' and 'to' distances of these units
were modified to increase the extent of these units by 4 km and 10 km in each
direction respectively, for the two queries. These newly created event tables were then
used with the complete coastal unit event database in the OVERLAYEVENTS
command using the INTERSECT subcommand. The resulting tables contained records
of all coastal units found that were within the boundaries of the extended barrier limits.
The ArcInfo FREQUENCY command was then run on the resulting tables to analyze
qualitatively for dominant coastal forms.
In this application of the OVERLAYEVENTS command, a coastal unit may
exist within the expanded extents of more than one barrier and, therefore, more than
one record will be created for that unit in the resultant table. Because a particular unit
may be counted more than once, a higher frequency of that type of unit is produced
precluding frequency data from being used quantitatively.
A total of 141 records with the form 'barrier' occur in the database for the
study area. The two most predominant forms found within 10 km of barriers are steep,
unconsolidated cliffs in the backshore and fringing beaches in the foreshore. In
descending order of occurrence these forms are followed by: steep, solid cliffs in the
backshore; solid outcrops in the foreshore; steep, solid cliffs in the foreshore; and solid
platforms in the foreshore. The two most predominant forms found within 4 km of
barriers are lagoons and fringing beaches in the foreshore. These are followed, in
descending order of occurrence, by: steep, unconsolidated cliffs in the backshore;
smooth, unconsolidated slopes in the backshore; flats in the foreshore; and wetlands.
In general terms, query on the 10 km extent demonstrates the dominant solid
forms that characterize the coast and includes unconsolidated coastal forms which may
nourish the barriers. The results from the 4 km extent query provide more coastal form
information specific to the barrier itself, as reflected in the predominance of lagoons,
foreshore flats and wetlands.
Dynamic Segmentation in the Coastal Information System
units which represented barrier beaches. The 'from' and 'to' distances of these units
were modified to increase the extent of these units by 4 km and 10 km in each
direction respectively, for the two queries. These newly created event tables were then
used with the complete coastal unit event database in the OVERLAYEVENTS
command using the INTERSECT subcommand. The resulting tables contained records
of all coastal units found that were within the boundaries of the extended barrier limits.
The ArcInfo FREQUENCY command was then run on the resulting tables to analyze
qualitatively for dominant coastal forms.
In this application of the OVERLAYEVENTS command, a coastal unit may
exist within the expanded extents of more than one barrier and, therefore, more than
one record will be created for that unit in the resultant table. Because a particular unit
may be counted more than once, a higher frequency of that type of unit is produced
precluding frequency data from being used quantitatively.
A total of 141 records with the form 'barrier' occur in the database for the
study area. The two most predominant forms found within 10 km of barriers are steep,
unconsolidated cliffs in the backshore and fringing beaches in the foreshore. In
descending order of occurrence these forms are followed by: steep, solid cliffs in the
backshore; solid outcrops in the foreshore; steep, solid cliffs in the foreshore; and solid
platforms in the foreshore. The two most predominant forms found within 4 km of
barriers are lagoons and fringing beaches in the foreshore. These are followed, in
descending order of occurrence, by: steep, unconsolidated cliffs in the backshore;
smooth, unconsolidated slopes in the backshore; flats in the foreshore; and wetlands.
In general terms, query on the 10 km extent demonstrates the dominant solid
forms that characterize the coast and includes unconsolidated coastal forms which may
nourish the barriers. The results from the 4 km extent query provide more coastal form
information specific to the barrier itself, as reflected in the predominance of lagoons,
foreshore flats and wetlands.