Displaying geographic routes

It consists of a Perl module GPS::Tracer that does collect and re-format routing data, and from examples of several JavaScript functions that display collected data using Google Maps.

The tool was developed primarily to read data from the customer web site provided by Guardian Mobility for their product "Tracer" (data are published there after they are collected from the Globastar satellites). However, it was made flexible enough that it can also read data from a simple CSV format ("comma-separated values") instead from their secured web site.

The original motivation for creating the tool was the Arctic student expedition FrozenFive (2007) where you can see their original route, created by the very same tool.

Architecture

Perl module

JavaScript

Google Map needs your own key

In order to display a Google Map in your web page, you need to sign up for a Google Maps API key here. Once you have it, put it directly into your page, in its head section. You may have more than one Google key if you want to show the same page from various web servers. For example:

<!-- make this page runable from several servers, with different Google Maps keys -->
<script language="javascript" type="text/javascript">
function include (script_url) {
   document.write ('<' + 'script');
   document.write (' language="javascript"');
   document.write (' type="text/javascript"');
   document.write (' src="' + script_url + '">');
   document.write ('</' + 'script' + '>');
}

var hostname = document.location.hostname;
var key;
if (hostname == "localhost")
   key = "ABQIAAAAZhe5F7Vv-1Xq9DDyIlEQXxT2yXp_ZAY8_ufC3CFXhHIE1NvwkxSg6J0s1S0DuVD-dFi2DIRpZq2LOg";
else if (hostname == "...")
   key = "...";
else if (hostname == "...")
   key = "...";
else if (hostname == "...")
   key = "...";

include ("http://maps.google.com/maps?file=api&v=2&key=" + key);
</script>

Loading function

We want to do some actions (such as prepare a Google Map) when a web page loads. There are two ways to do it. One is to call it directly in the body HTML tag, and one is to overwrite the window.onload function at the end of the page body. The latter case allows more flexibility (also it allows displaying a text, for example Loading..., during the loading time). The example uses the latter one, and the loading is in the file examples/loading.js.

Displaying Google Maps

It is done by functions in the file examples/tracer.js. Of course, these function need to get data produced by the Perl module GPS::Tracer. The JavaScript is hopefully self-explanatory. Just one comment: it has a hard-coded location of the map. However, it could be done better, by reading the first marker first and use its location as the map centre.

Displaying summary

It is done by functions in the file examples/summary.js. It just displays "so far travelled" kilometres as read from the examples/data/output-summary.xml file. As it is done, it uses a machine gun to kill a mosquito. It needs to read just one attribute from a very short XML file and it uses the full-flown tool examples/prototype.js to do it. One solution is to use the same functionality from the Google Maps API (even though this has nothing to do with any map).

HTML elements names

Last but not least, be aware that the example JavaScript files rely on some names of HTML elements in your web page. If you use different names, you need also to change the names in the scripts. The used names are errormsg, totalkms (used in summary.js file), and map, progressDisplay, markerCount, lastPoint, density (used in tracer.js file).

Sewing together Perl module and JavaScript

#!/usr/bin/perl -w
#
use strict;
use warnings;
use Net::FTP;

# --- Configuration section ---
my $server =     'YOUR_FTP_HOSTNAME';
my $user =       'YOUR_USER_NAME_FOR_THE_FTP_SERVER';
my $password =   '...AND_YOUR PASSWORD';
my $local_dir =  'data';
my $remote_dir = 'whatever/data';
# --- end of configuration ---

my @files = ('output-all.xml', 'output-distance.xml', 'output-oneperday.xml',
	     'output-summary.xml', 'output.csv', 'output-ozi.wpt',
	     'output-chart.png');

chdir $local_dir or die "Cannot cd to '$local_dir': $!\n";

my $ftp = Net::FTP->new ($server)
    or die "Cannot connect to $server: $@";
$ftp->login ($user, $password)
    or die "Cannot login: ", $ftp->message;
$ftp->pasv()
    or die "Cannot set passive mode: ", $ftp->message;
$ftp->binary()
    or die "Cannot set binary: ", $ftp->message;
$ftp->cwd ($remote_dir)
    or die "Cannot cd to '$remote_dir': ", $ftp->message;
foreach my $file (@files) {
    $ftp->put ($file)
	or die "Cannot upload '$file': ", $ftp->message;
}
$ftp->quit;

Comments and bug reports welcome