/ 
Geo-Distance-XS-0.12
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/ Geo::Distance::XS

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/

REQUESTS AND BUGS

Please report any bugs or feature requests to 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:

COPYRIGHT AND LICENSE

Copyright (C) 2009-2014 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>