GSHHS_DP(1gmt)
NAME
gshhs_dp - Line reduction using the Douglas-Peucker algorithm
SYNOPSIS
gshhs_dp input.b tolerance output.b [-v]
DESCRIPTION
gshhs_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 byteswabbing between different architectures.
- input.b
- GSHHS or WDBII binary data file as distributed with the GSHHS 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
gshhs_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.