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)