gshhs_dp(1) - Linux man page

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 byte-swabbing 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.