Geo::Distance::XS(3pm)					User Contributed Perl Documentation				    Geo::Distance::XS(3pm)

NAME

       Geo::Distance::XS - speed up Geo::Distance

SYNOPSIS

	   use Geo::Distance::XS;

	   my $geo = Geo::Distance->new;
	   my $distance = $geo->distance(mile => $lon1, $lat1 => $lon2, $lat2);

DESCRIPTION

       The "Geo::Distance::XS" module provides faster C implementations of the distance calculations found in "Geo::Distance".	See the
       documentation for that module for usage.

       NOTE: As of version 0.13, Geo::Distance automatically uses this module if it is installed.

FORMULAS

       In addition to the formulas offered in "Geo::Distance", this module implements the additional formulas:

   alt: Andoyer-Lambert-Thomas Formula
       This is faster than the Vincenty formula, but trades a bit of accuracy.

PERFORMANCE

       This distribution contains a benchmarking script which compares "Geo::Distance::XS" with "Geo::Distance" and "GIS::Distance::Fast". These
       are the results on a MacBook 2GHz with Perl 5.14.2:

	   ---- [ Formula: hsin ] ------------------------------------
	   perl     - distance from LA to NY: 2443.08796228363 miles
	   xs	    - distance from LA to NY: 2443.08796228363 miles
	   gis_fast - distance from LA to NY: 2443.08796228363 miles

		       Rate gis_fast	 perl	    xs
	   gis_fast   24802/s	    --	   -70%     -98%
	   perl       81919/s	  230%	     --     -92%
	   xs	    1003704/s	 3947%	  1125%       --

	   ---- [ Formula: tv ] ------------------------------------
	   perl     - distance from LA to NY: 2448.24135235512 miles
	   xs	    - distance from LA to NY: 2448.2413523656 miles
	   gis_fast - distance from LA to NY: 2448.24135235512 miles

		       Rate	perl gis_fast	    xs
	   perl      18101/s	   --	  -19%	   -95%
	   gis_fast  22330/s	  23%	    --	   -94%
	   xs	    345717/s	1810%	 1448%	     --

	   ---- [ Formula: polar ] ------------------------------------
	   perl     - distance from LA to NY: 2766.02509696782 miles
	   xs	    - distance from LA to NY: 2766.02509696782 miles
	   gis_fast - distance from LA to NY: 2766.02509696782 miles

		       Rate gis_fast	 perl	    xs
	   gis_fast   19200/s	    --	   -78%     -98%
	   perl       87682/s	  357%	     --     -93%
	   xs	    1214700/s	 6227%	  1285%       --

	   ---- [ Formula: cos ] ------------------------------------
	   perl     - distance from LA to NY: 2443.08796228363 miles
	   xs	    - distance from LA to NY: 2443.08796228363 miles
	   gis_fast - distance from LA to NY: 2443.08796228363 miles

		       Rate gis_fast	 perl	    xs
	   gis_fast   24435/s	    --	   -69%     -98%
	   perl       78913/s	  223%	     --     -93%
	   xs	    1147836/s	 4597%	  1355%       --

	   ---- [ Formula: gcd ] ------------------------------------
	   perl     - distance from LA to NY: 2443.08796228363 miles
	   xs	    - distance from LA to NY: 2443.08796228363 miles
	   gis_fast - distance from LA to NY: 2443.08796228363 miles

		       Rate gis_fast	 perl	    xs
	   gis_fast   18270/s	    --	   -75%     -98%
	   perl       74472/s	  308%	     --     -93%
	   xs	    1102769/s	 5936%	  1381%       --

	   ---- [ Formula: mt ] ------------------------------------
	   perl     - distance from LA to NY: 2443.08796228363 miles
	   xs	    - distance from LA to NY: 2443.08796228363 miles
	   gis_fast - distance from LA to NY: 2443.08796228363 miles

		       Rate gis_fast	 perl	    xs
	   gis_fast   17935/s	    --	   -75%     -98%
	   perl       71739/s	  300%	     --     -94%
	   xs	    1135525/s	 6231%	  1483%       --

       This distribution contains another benchmarking script which compares only the XS formulas over several different coordinates:

		   Rate    tv  hsin   alt   cos    mt	gcd polar
	   tv	  16906/s    --  -90%  -90%  -91%  -91%  -91%  -92%
	   hsin  165414/s  878%    --	-4%   -8%  -10%  -13%  -17%
	   alt	 172032/s  918%    4%	 --   -5%   -7%   -9%  -14%
	   cos	 180326/s  967%    9%	 5%    --   -2%   -5%  -10%
	   mt	 184357/s  991%   11%	 7%    2%    --   -3%	-8%
	   gcd	 189253/s 1019%   14%	10%    5%    3%    --	-6%
	   polar 200386/s 1085%   21%	16%   11%    9%    6%	 --

	   Calculated length for short distance:
	       alt  : 40.3740136064528 miles
	       cos  : 40.3095459813536 miles
	       gcd  : 40.3095459813294 miles
	       hsin : 40.3095459813294 miles
	       mt   : 40.3095459813536 miles
	       polar: 46.7467797109043 miles
	       tv   : 40.3740136384531 miles

	   Calculated length for long distance:
	       alt  : 2448.24135691376 miles
	       cos  : 2443.08796228363 miles
	       gcd  : 2443.08796228363 miles
	       hsin : 2443.08796228363 miles
	       mt   : 2443.08796228363 miles
	       polar: 2766.02509696782 miles
	       tv   : 2448.2413523656 miles

	   Calculated length for nearly antipodes:
	       alt  : 12340.6455133245 miles
	       cos  : 12340.327635068 miles
	       gcd  : 12340.327635068 miles
	       hsin : 12340.327635068 miles
	       mt   : 12340.327635068 miles
	       polar: 12368.4764642469 miles
	       tv   : 12340.7483034002 miles

	   Calculated length for antipodes:
	       alt  : 12429.86673988 miles
	       cos  : 219.005548031861 miles
	       gcd  : 12438.0476860875 miles
	       hsin : 12438.0475680956 miles
	       mt   : 219.005548031861 miles
	       polar: 12438.0476860875 miles
	       tv   : 12370.1885059814 miles

	   Calculated length for polar antipodes:
	       alt  : 12429.86673988 miles
	       cos  : 12438.0476860875 miles
	       gcd  : 12438.0476860875 miles
	       hsin : 12438.0476860875 miles
	       mt   : 12438.0476860875 miles
	       polar: 12438.0476860875 miles
	       tv   : 12429.8667398787 miles

SEE ALSO

       Geo::Distance

       http://blogs.esri.com/esri/apl/2010/09/28/fast-times-at-geodesic-high/ <http://blogs.esri.com/esri/apl/2010/09/28/fast-times-at-geodesic-
       high/>

REQUESTS AND BUGS

       Please report any bugs or feature requests to http://rt.cpan.org/Public/Bug/Report.html?Queue=Geo-Distance-XS
       <http://rt.cpan.org/Public/Bug/Report.html?Queue=Geo-Distance-XS>. I will be notified, and then you'll automatically be notified of
       progress on your bug as I make changes.

SUPPORT

       You can find documentation for this module with the perldoc command.

	   perldoc Geo::Distance::XS

       You can also look for information at:

       o   GitHub Source Repository

	   http://github.com/gray/geo-distance-xs <http://github.com/gray/geo-distance-xs>

       o   AnnoCPAN: Annotated CPAN documentation

	   http://annocpan.org/dist/Geo-Distance-XS <http://annocpan.org/dist/Geo-Distance-XS>

       o   CPAN Ratings

	   http://cpanratings.perl.org/d/Geo-Distance-XS <http://cpanratings.perl.org/d/Geo-Distance-XS>

       o   RT: CPAN's request tracker

	   http://rt.cpan.org/Public/Dist/Display.html?Name=Geo-Distance-XS <http://rt.cpan.org/Public/Dist/Display.html?Name=Geo-Distance-XS>

       o   Search CPAN

	   http://search.cpan.org/dist/Geo-Distance-XS/ <http://search.cpan.org/dist/Geo-Distance-XS/>

COPYRIGHT AND LICENSE

       Copyright (C) 2009-2012 gray <gray at cpan.org>, all rights reserved.

       This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

AUTHOR

       gray, <gray at cpan.org>

perl v5.14.2							    2012-04-14						    Geo::Distance::XS(3pm)