GSHHS_DP(1gmt)						       Generic Mapping Tools						    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 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 cari-
       cature, 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), gshhs(1), gshhstograss(1)

GMT 4.5.7							    15 Jul 2011 						    GSHHS_DP(1gmt)