/ 
Image-Maps-Plot-FromPostcode-0.021
River stage zero No dependents
/ Image::Maps::Plot::FromPostcode

NAME

Image::Maps::Plot::FromPostcode - where in the world are London.pm members?

SYNOPSIS

use Image::Maps::Plot::FromPostcode;

new Image::Maps::Plot::FromPostcode (MAP=>"THE WORLD","PATH"=>"E:/src/pl/out.html");

# or

Image::Maps::Plot::FromPostcode::all("E:/src/pl/");
__END__

DESCRIPTION

Plots postcode-defined points on JPEG maps, and creates an HTML page with an image map to display the image.

I was bored and got this message:

From: london.pm-admin@london.pm.org
[mailto:london.pm-admin@london.pm.org]On Behalf Of Philip Newton
Sent: 21 June 2001 11:44
To: 'london.pm@london.pm.org'
Subject: Re: headers

Simon Wistow wrote:
> It's more a collection of people who have the common connection
> that they live and london and like perl.
> In fact neither of those actually have to be true since I personally
> know two people on the list who don't program Perl and one of whom
> doesn't even live in London.

How many off-London people have we got? (Well, also excluding people who
live near London.)

From outside the UK, there's Damian, dha, Paul M, I; Lucy and lathos
probably also qualify as far as I can tell. Marcel used to work in London
(don't know whether he still does). Anyone else?

Cheers,
Philip
--
Philip Newton <Philip.Newton@datenrevision.de>
All opinions are my own, not my employer's.
If you're not part of the solution, you're part of the precipitate.

In the twenty-second weekly summary of the London Perl Mongers mailing list, for the week starting 2001-06-18:

In other news: ... a london.pm world map ...

PREREQUISITES

Data::Dumper;
File::Basename;
GD;
strict;
warnings.
WWW::MapBlast

DISTRIBUTION CONTENTS

In addition to this file, the distribution relies upon the included files:

.earth.dat
london_postcodes.jpg
uk.jpg
world.jpg

EXPORTS

None. They're dirty dirty dirty.

CAVEATS

The exmaple map, london_postcodes.jpg, is inaccurate.

Whilst degrees of latitude are accurate to two decimal places, Degrees of longitude are taken to be 69 miles. This will be adjusted in a later version.

All images must be JPEGs - PNG or other support could easily be added.

USEAGE METHODS

new

Not really a constructor, as it does not return a new object of this class, but does the whole job of loding, creating and saving the files, so maybe it shouldn't be called new.

Accepts arguments in a hash, where keys/values are as follows:

MAP

Either THE WORLD, THE UK, A BAD MAP OF LONDON, or any other key to the %MAPS hash defined elsewhere, and documented below.

PATH

The path at which to save - will use the filename you supply, but please include an extension, coz I'm lazy. You will receive a .jpg and .html file in return.

DBNAME

Name of the configuration/db file - defaults to .earth.dat, which comes with the distribution.

CHAT

Set if you want rabbit on the screen.

CREATIONTXT

Text output onto the image. Defaults to 'Created on <date> by <package>.';

TITLE

Title text to include on the image (in bold) and as the content of the HTML page's TITLE element: is appended with the name of the map. This defaults to London.pm, where this module originates.

INCLUDEANCHOR

Set if you wish the map's anchor point to be included in the output.

FNPREFIX

Filename prefix - added to the start of all files output except the db file. Default is m_.

&all (base_path,base_url)

A subroutine, not a method, that produces all available maps, and an index page.

It accepts four arguments, a path at which files can be built, a filename prefix (see "new"), a title, and blurb to add beneath the list of hyperlinks to the maps.

The following files are produced:

    m_MAPNAME.jpg * number of maps m_MAPNAME.html * number of maps m_index.html

where MAPNAME is ... the name of the map. The m_ prefix is held in the instance variable FNPREFIX. You may also wish to look at and adjust the instance variable CREATIONTXT.

&save_db

A subroutine, not a method, that saves the database to the filename specified as the only arguemnt.

Returns nothing, but does die on failure.

&add_entry

A subroutine, not a method, that accepts: $name, $country, $postcode

Looks up on MapBlast.com the supplied details, and adds them to the db.

If an entry already exists for $name, will return undef unless the global scalar $ADDENTRY is set to it's default value of MULTIPLE, in which case $name will be appended with $country and $postcode.

Does not save them to file - you must do that manually ("save_db").

Incidentaly returns a reference to the new key.

&remove_entry

A subroutine, not a method, that accepts the name field of the entry in the db, and returns 1 on success, undef if no such entry exists.

NOTES ON LATITUDE AND LONGITUDE

After http://www.mapblast.com/myblast/helpFaq.mb#2:

    Zero degrees latitude is the equator, with the North pole at 90 degrees latitude and the South pole at -90 degrees latitude. one degree is approximately 69 miles. Greenwich, England is at 51.466 degrees north of the equator.

    Zero degrees longitude goes through Greenwich, England. Again, Each 69 miles from this meridian represents approximately 1 degree of longitude. East/West is plus/minus respectively.

Actually, latitude and longitude vary depending upon the degree in hand: see The Compton Encyclopdedia for more information.

ADDING MAPS

The next version, if there is one, may allow you to pass map data to the constructor. In the meantime, adding maps is not in itself a big deal, perl-wise. Add a new key to the %MAPS hash, with the value of an anonymous hash with the following content:

FILE

scalar file name of map

DIM

anon array of dimensions of map in pixels [x,y]. You could create DIM on the fly using GD, but there's probably no point, as you're almost certainly going to have to edit the map to align it with longitude and latitude (if you find a stock of public-domain maps that are already aligned, please drop the author a line).

SPOTSIZE

scalar number for the size of the map-marker spots, in pixels

ANCHOR_PIXELS

anon array of the pixel location of the arbitrary anchor pont [x,y]

ANCHOR_LATLON

anon array of the latitude/longitude of the arbitrary anchor pont [x,y]

ANCHOR_NAME

scalar name of the anchor, when marked on map

ANCHOR_PLACE

scalar place name of the anchor, when marked on map

ONEMILE

scalar representation of 1 mile in pixels

SEE ALSO

perl(1); GD; File::Basename; Acme::Pony; Data::Dumper; WWW::MapBlast.

THANKS

Thanks to the London.pm group for their test data and insipration, to Leon for his patience with all that mess on the list, to Philip Newton for his frankly amazing knowledge of international postcodes.

Thanks also to About.com, The University of Texas, and The Ordnance Survey for their public-domain maps.

AUTHOR

Lee Goddard <lgoddard@cpan.org>

COPYRIGHT

Copyright (C) Lee Goddard, 2001. All Rights Reserved.

This module is supplied and may be used under the same terms as Perl itself.

The public domain maps provided with this distribution are the property of their respective copyright holders.