GSHHG_DP(1) Generic Mapping Tools GSHHG_DP(1)NAMEgshhg_dp - Line reduction using the Douglas-Peucker algorithm
SYNOPSISgshhg_dp input.b tolerance output.b [-v]
DESCRIPTIONgshhg_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 carica‐
ture, 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 ALSOGMT(1), gshhg(1), gshhgtograss(1)GMT 4.5.14 1 Nov 2015 GSHHG_DP(1)
