NAME

       gshhg_dp - Line reduction using the Douglas-Peucker algorithm

SYNOPSIS

       gshhg_dp input.b tolerance output.b [-v]

DESCRIPTION

       gshhg_dp  reads  the binary coastline (GSHHS) or political boundary or river (WDBII) files
       and and reduces the complexity of the line by applying the Douglas-Peucker algorithm.   It
       automatically handles byte-swabbing between different architectures.

       input.b
              GSHHS or WDBII binary data file as distributed with the GSHHG data supplement.  Any
              of the 5 standard resolutions (full, high, intermediate, low, crude) can be used.

       tolerance
              tolerance is maximum mismatch in km.  The larger the value the more reduction  will
              take place.

       output.b
              The reducted data set.

OPTIONS

       -v     Reports progress and statistics while running.

EXAMPLES

       To simplify the full GSHHS data set with a custom tolerance of 2 km, try

       gshhg_dp gshhs_f.b 2 gshhs_2km.b

REFERENCES

       Douglas,  D.  H.,  and T. K. Peucker, Algorithms for the reduction of the number of points
       required to represent a digitized line of its  caricature,  Can.  Cartogr.,  10,  112-122,
       1973.

AUTHOR

       This implementation of the D-P algorithm has been kindly provided by Dr. Gary J. Robinson,
       Environmental Systems Science Centre, University of Reading, Reading, UK (gazza@mail.nerc-
       essc.ac.uk); his subroutine forms the basis for this program.

SEE ALSO

       GMT(1), gshhg(1), gshhgtograss(1)