从最近上传的KML文件初始化Google Maps API

Question

so I am making a simple website with the initial feature simply being thus:

The user uploads a KML file to the website. The Google Maps API is initialised using this KML file, so that a map is shown with their recent movements.

Now this sounds very simple but I'm having some trouble with the basics. This is more or less my first foray into web development so I'm trying to learn HTML, CSS, AJAX, PHP, Google Maps API V3, and of course the KML file format.

To initialise the Google Maps API using a KML file, one must first set up some basic information such as this:

function initialize() {
  var myLatlng = new google.maps.LatLng(40.65, -73.95);
  var myOptions = {
    zoom: 12,
    center: myLatlng,
    mapTypeId: google.maps.MapTypeId.ROADMAP
  };

The important bit to look at here being where to center the map.

As well as this, one must specify which KML file to use:

var nyLayer = new google.maps.KmlLayer(
      'http://www.searcharoo.net/SearchKml/newyork.kml',
      {  suppressInfoWindows: true,
         map: map});

These are of course just examples, not the data I will be using.

Now my problem is such. These values seem to be predetermined and static. To initialise the Google Maps API these values need to be known beforehand. But in my case, these values will not be known UNTIL the user uploads the KML file.

Thus far I have a simple PHP script to handle file uploads. I do not know how to pass control over to the JavaScript containing the setup for Google Maps, or how to write this code such that the values which are only known once the file has been uploaded are used to initilialise the map.

In summary, what I mean to achieve is this:

User browses to KML file. User presses "Upload" button. File is uploaded and then immediately used to initialise a map showing their movements.

I may have written too much but I figure it's best to write too much than not enough. Thanks in advance for your advice.

Answer 1

Given the code snippets you have posted, the KmlLayer should center and zoom to show the contents of the kml file. If it is not doing that, please provide enough information to reproduce the problem (the kml file and an html/js file that displays it).

EDIT: You wrote:

I need my php file upload script to save the name of the KML file, and then somehow I need to extract information regarding where the map should be centred,

You don't need to do that unless you don't like the default behavior of center and zoom the map to display all the content of the kml

and then call the Google Maps API (which I believe is JavaScript) with the information I've just extracted. This all needs to be done with one press of the Upload button.

Yes.

EDIT2:

Okay, but how? I don't know what to do. This is my first attempt at web development. I'm not asking for someone to write the code for me, but pointers on how to do this

Step 1: This example from the documentation shows how to display a kml file, replace the reference to 'http://gmaps-samples.googlecode.com/svn/trunk/ggeoxml/cta.kml' with the reference to the kml file you want to display.

Step 2: change your php to generate the html and javascript required to load and display it when the button is clicked. How that works will depend on where on your page you want to display it and whether you want it to be a hidden div that is displayed when the button is clicked, a new window, or something else.