/ 
Geo-Distance-XS-0.10
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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  23209/s       --     -72%     -98%
perl      82707/s     256%       --     -92%
xs       998734/s    4203%    1108%       --

---- [ Formula: tv ] ------------------------------------
perl     - distance from LA to NY: 2448.24135235512 miles
xs       - distance from LA to NY: 2448.48844386882 miles
gis_fast - distance from LA to NY: 2448.24135235512 miles

            Rate     perl gis_fast       xs
perl      18797/s       --     -13%     -95%
gis_fast  21525/s      15%       --     -94%
xs       344063/s    1730%    1498%       --

---- [ 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   19166/s       --     -78%     -98%
perl       87682/s     357%       --     -93%
xs       1226609/s    6300%    1299%       --

---- [ 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   23424/s       --     -71%     -98%
perl       80388/s     243%       --     -93%
xs       1117090/s    4669%    1290%       --

---- [ 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   18101/s       --     -75%     -98%
perl       73770/s     308%       --     -93%
xs       1092266/s    5934%    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   17454/s       --     -75%     -98%
perl       70149/s     302%       --     -94%
xs       1147836/s    6476%    1536%       --

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

        Rate    tv  hsin   alt    mt   cos   gcd polar
tv     16593/s    --  -90%  -91%  -91%  -91%  -91%  -92%
hsin  170328/s  927%    --   -4%   -7%   -7%  -13%  -17%
alt   177535/s  970%    4%    --   -3%   -3%   -9%  -14%
mt    182781/s 1002%    7%    3%    --   -1%   -6%  -11%
cos   183794/s 1008%    8%    4%    1%    --   -6%  -11%
gcd   194708/s 1073%   14%   10%    7%    6%    --   -6%
polar 206279/s 1143%   21%   16%   13%   12%    6%    --

Calculated length for short distance:
    alt  : 40.3547210428874 miles
    cos  : 40.3095459813536 miles
    gcd  : 40.3095459813294 miles
    hsin : 40.3095459813294 miles
    mt   : 40.3095459813536 miles
    polar: 46.7467797109043 miles
    tv   : 40.3780884309995 miles

Calculated length for long distance:
    alt  : 2445.82594045448 miles
    cos  : 2443.08796228363 miles
    gcd  : 2443.08796228363 miles
    hsin : 2443.08796228363 miles
    mt   : 2443.08796228363 miles
    polar: 2766.02509696782 miles
    tv   : 2448.48844386882 miles

Calculated length for nearly antipodes:
    alt  : 12354.157484494 miles
    cos  : 12340.327635068 miles
    gcd  : 12340.327635068 miles
    hsin : 12340.327635068 miles
    mt   : 12340.327635068 miles
    polar: 12368.4764642469 miles
    tv   : 12341.9938071999 miles

Calculated length for antipodes:
    alt  : 12431.1212380871 miles
    cos  : 219.005548031861 miles
    gcd  : 12438.0476860875 miles
    hsin : 12438.0475680956 miles
    mt   : 219.005548031861 miles
    polar: 12438.0476860875 miles
    tv   : 12371.4369809266 miles

Calculated length for polar antipodes:
    alt  : 12431.1212380871 miles
    cos  : 12438.0476860875 miles
    gcd  : 12438.0476860875 miles
    hsin : 12438.0476860875 miles
    mt   : 12438.0476860875 miles
    polar: 12438.0476860875 miles
    tv   : 12431.1212380419 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) 2009-2012 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>