how to use the google maps api with greasemonkey to read a table of addresses and trace the route?

Question

There is a website which holds the buses routes for my city (Porto Alegre - Brazil) in a table.

ex: EPTC

Using Greasemonkey to load de Google Maps API, id like to show a fixed map at the top right corner of the screeen.

The script must read the street names from the table, strip de extra spaces (there are a lot of them), and draw the route in the right order.

Answer 1

Here is the Greasemonkey compatible script to accomplish the task: http://userscripts.org/scripts/show/116339

Key points:

1- find the table and loop through each cell to get the content
2- strip all the extra white spaces and save the text in an array
3- create two DIVs, one inside the other (otherwise the position will not be fixed)
4- append the DIVs to the page and call the API
5- "google" must be called with unsafeWindow (google = unsafeWindow.google)

API_js_callback = "http://maps.google.com/maps/api/js?sensor=false&region=BR&callback=initialize";

var script = document.createElement('script');
    script.src = API_js_callback;
    var head = document.getElementsByTagName("head")[0];
    (head || document.body).appendChild(script);

if (document.getElementsByTagName('TABLE')[0] != null) {
    var Tabela_1 = document.getElementsByTagName('TABLE')[0];
    var Tabela_1_cel = Tabela_1.getElementsByTagName('TD');
    var Tabela_1_lin = Tabela_1.getElementsByTagName('TR');
}

if (document.getElementsByTagName('TABLE')[1] != null) {
    var Tabela_2 = document.getElementsByTagName('TABLE')[1];
    var Tabela_2_cel = Tabela_2.getElementsByTagName('TD');
    var Tabela_2_lin = Tabela_2.getElementsByTagName('TR');
}

var DIVmapa = document.createElement('div');
    DIVmapa.id = 'DIVmapa';
    DIVmapa.style.border = '2px coral solid';
    DIVmapa.style.cursor = 'pointer';
    DIVmapa.style.display = '';
    DIVmapa.style.height = '75%';
    DIVmapa.style.margin = '1';
    DIVmapa.style.position = 'fixed';
    DIVmapa.style.padding = '1';
    DIVmapa.style.right = '1%';
    DIVmapa.style.top = '1%';
    DIVmapa.style.width = '30%';
    DIVmapa.style.zIndex = '99';

var DIVinterna = document.createElement('div');
    DIVinterna.id = 'DIVinterna';
    DIVinterna.style.height = '100%';
    DIVinterna.style.width = '100%';
    DIVinterna.style.zIndex = '999';

if (Tabela_1 || Tabela_2) {
    document.body.appendChild(DIVmapa);
    DIVmapa.appendChild(DIVinterna);
}

initialize = setTimeout(function () {
    google = unsafeWindow.google;
    directionsService = new google.maps.DirectionsService();
    directionsDisplay = new google.maps.DirectionsRenderer();

    var PortoAlegre = new google.maps.LatLng(-30.034176,-51.229212);
    var myOptions = {
        zoom: 14,
        mapTypeId: google.maps.MapTypeId.ROADMAP,
        center: PortoAlegre
    }

    map = new google.maps.Map(document.getElementById("DIVinterna"), myOptions);
    directionsDisplay.setMap(map);

    function calcRoute() {
        var start = Tabela_1_cel[1].getElementsByTagName('B')[0].innerHTML.replace(/\s{2,}/g, ' ') + ' Porto Alegre';
        var end = Tabela_1_cel[10].getElementsByTagName('B')[0].innerHTML.replace(/\s{2,}/g, ' ') + ' Porto Alegre';
        var waypts = [];
        //for (var i=1; i<Tabela_1_cel.length; i++) {
        for (var i=2; i<10; i++) {
            ponto_1 = Tabela_1_cel[i].getElementsByTagName('B')[0].innerHTML;
            semespacos_1 = ponto_1.replace(/\s{2,}/g, ' ') + ' Porto Alegre'; 
            waypts.push({location: semespacos_1, stopover: true});
        }

        var request = {
            origin: start, 
            destination: end,
            waypoints: waypts,
            optimizeWaypoints: false,
            travelMode: google.maps.DirectionsTravelMode.DRIVING
        };

        directionsService.route(request, function(response, status) {
            if (status == google.maps.DirectionsStatus.OK) {directionsDisplay.setDirections(response)};
            //alert(status);
        });
    }

    calcRoute();
}, 1000);

Enjoy! :)