Image/Maps/Plot/FromPostcode version 1

Image/Maps/Plot/FromPostcode version 1
======================================

NAME
Image::Maps::Plot::FromPostcode - plots postcodes on world/regional map
images/HTML

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

# Create a single map

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

# Create all possible maps

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

# Add a user to the db

Image::Maps::Plot::FromPostcode::load_db (".earth.dat");
Image::Maps::Plot::FromPostcode::add_entry ('Peter Smith','United Kingdom','BS7 29JT');
Image::Maps::Plot::FromPostcode::save_db (".london.pm.dat");

__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 on a list:

From: [email protected]
[mailto:[email protected]]On Behalf Of Philip Newton
Sent: 21 June 2001 11:44
To: '[email protected]'
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 <[email protected]>
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 ...

Hence the module.

PREREQUISITES
Data::Dumper;
File::Basename;
GD;
strict;
warnings.
WWW::MapBlast 0.02
Image::GD::Thumbnail 0.011

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 with thumbnails.

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

An index page will be produced, linking to the following files for each
map:

m_"MAPNAME".jpg m_"MAPNAME"_t.jpg m_"MAPNAME".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".

&load_db

A subroutine that loads a database hash from the specified path.

Returns nothing, but does "die" on failure.

&save_db

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

Note tha tyou may want to load a db before saving.

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 (the section on
"save_db"), but note that you may wish to load the db before adding to
it and saving.

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

REVSIONS
0.25 Clean IMG path and double-header bugs 0.22 Added thumbnail images
to index page 0.23 Added more documentation; escaping of href text

SEE ALSO
perl(1); the GD manpage; the File::Basename manpage; the Acme::Pony
manpage; the Data::Dumper manpage; the WWW::MapBlast manpage; the
Image::GD::Thumbnail manpage

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 <[email protected]>

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.