CODEWITHSUNDEEP
htmlgeolocationip-geolocation
Morison
Morison

Reputation: 1165

geolocation in google map and HTML5

I am working on location based service. I couldn't find any clear answer related to my following queries and so am asking-

How to enable HTML5 geolocation in our own server? Or is there any central geolocation DB there which will provide location service by default (like DNS)?

I was stunned seeing the accuracy of geolocation in google map (http://html5demos.com/geo) in my laptop (obviously GPS free) which is within ~20M range. What is the technology? How to implement that in our own system?

When I used to search my IP location, it used to show the ISP office in the map which is ~15 KM further as opposed to recent situation where it is showing almost exact location. What might be the reason? could it be because I use my android phone using the same Wireles router and it takes the location from there? Or in HTML5 they started locating specific IP addresses (which seems somewhat unlikely).

Upvotes: 2

Views: 7029

Answers (5)

Jeevan Roy dsouza
Jeevan Roy dsouza

Reputation: 673

Try This Code

<!DOCTYPE html>
<html>
  <head>
    <title>Geolocation</title>
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no">
    <meta charset="utf-8">
    <style>
      html, body, #map-canvas {
        height: 100%;
        margin: 0px;
        padding: 0px
      }
    </style>
    <!--
    Include the maps javascript with sensor=true because this code is using a
    sensor (a GPS locator) to determine the user's location.
    See: https://developers.google.com/maps/documentation/javascript/tutorial#Loading_the_Maps_API
    -->
    <script src="https://maps.googleapis.com/maps/api/js?v=3.exp&sensor=true"></script>

    <script>
// Note: This example requires that you consent to location sharing when
// prompted by your browser. If you see a blank space instead of the map, this
// is probably because you have denied permission for location sharing.

var map;

function initialize() {
  var mapOptions = {
    zoom: 6
  };
  map = new google.maps.Map(document.getElementById('map-canvas'),
      mapOptions);

  // Try HTML5 geolocation
  if(navigator.geolocation) {
    navigator.geolocation.getCurrentPosition(function(position) {
      var pos = new google.maps.LatLng(position.coords.latitude,
                                       position.coords.longitude);

      var infowindow = new google.maps.InfoWindow({
        map: map,
        position: pos,
        content: 'Location found using HTML5.'
      });

      map.setCenter(pos);
    }, function() {
      handleNoGeolocation(true);
    });
  } else {
    // Browser doesn't support Geolocation
    handleNoGeolocation(false);
  }
}

function handleNoGeolocation(errorFlag) {
  if (errorFlag) {
    var content = 'Error: The Geolocation service failed.';
  } else {
    var content = 'Error: Your browser doesn\'t support geolocation.';
  }

  var options = {
    map: map,
    position: new google.maps.LatLng(60, 105),
    content: content
  };

  var infowindow = new google.maps.InfoWindow(options);
  map.setCenter(options.position);
}

google.maps.event.addDomListener(window, 'load', initialize);

    </script>
  </head>
  <body>
    <div id="map-canvas"></div>
  </body>
</html>

Upvotes: 0

Sheikh Ali
Sheikh Ali

Reputation: 1544

function GetGeolocation() {

navigator.geolocation.getCurrentPosition(GetCoords, GetError);

}

now check the GetCords function

function GetCoords(position){

alert('latitude: '+ position.coords.latitude);

alert('longitude: '+ position.coords.longitude);

alert('accuracy: '+ position.coords.accuracy);

FindmeOnMap(position.coords.latitude, position.coords.longitude);

}

Upvotes: 2

Colin Pickard
Colin Pickard

Reputation: 46633

You can find a lot of information on how this works and how to use it in your own websites in the excellent Dive Into HTML 5. This book recommends using Modernizr, a simple example of which is provided: 

function get_location() {
if (Modernizr.geolocation) {
navigator.geolocation.getCurrentPosition(show_map);
} else {
// no native support; maybe try Gears?
} 
}

The primary way it is working on your laptop is by using the known positions of local wireless access points. This varies a little from browser to browser - firefox has a good explanation here. They use positioning services from Google, which were created by mapping done by Google's Street View cars.

Upvotes: 3

Two pi
Two pi

Reputation: 256

It's actually pretty simple. The above example from Dive into HTML is incomplete, as it doesn't show the show_map function, which is a user-created function that actually reads the incoming data and does something with it. Here's a more complete example:

<!DOCTYPE HTML>

<html lang = "en">

<head>

  <title>location.html</title>

  <meta charset = "UTF-8" />

  <script type = "text/javascript">

  //<![CDATA[



  function getLoc(){

    navigator.geolocation.getCurrentPosition(showMap);

  } // end getLoc



  function showMap(position){

    var lat = position.coords.latitude;

    var long = position.coords.longitude;

    var linkUrl = "http://maps.google.com?q=" + lat + "," + long;

    var mapLink = document.getElementById("mapLink");

    mapLink.href = linkUrl;

    var embedMap = document.getElementById("embedMap");

    embedMap.src = linkUrl + "&z=16&amp;output=embed";

  } // end showMap



  //]]>

  </script>

</head>



<body onload = "getLoc()">

  <h1>Geolocation Demo</h1>



  <p>

    <a id = "mapLink"

       href = "http://maps.google.com">click for a map</a>

  </p>



<iframe id = "embedMap"

        width="800" 

        height="500" 

        frameborder="0" 

        scrolling="no" 

        marginheight="0" 

        marginwidth="0" 

        src= "">

</iframe><br />



</body>

</html>

This example (from my upcoming HTML5 book) has a getLoc() function called by the body onload mechanism. This uses the navigator.geolocation.getCurrentPosition() function to request a permission vector. It will pop up a permission dialog, which will be rejected if the user chooses not to share her current position. If the user does play along, the indicated callback function (in my case showMap) will be displayed.

The callback function automatically accepts a special position object as its only parameter. This object has a number of potentially useful attributes, but latitude and longitude are the most helpful. You can use these values to simply print out the current position. You can also concatenate these values into a Google maps URL to get a quick Google map of the current location. I also embedded a Google map into my current page, and changed the URL of the embedded (iframe) map to get immediate feedback.

Hope this helps!

Upvotes: 0

Barkermn01
Barkermn01

Reputation: 6822

// Check for geolocation support
if (navigator.geolocation) {
    // Use method getCurrentPosition to get coordinates
    navigator.geolocation.getCurrentPosition(function (position) {
        // Access them accordingly
        alert(position.coords.latitude + ", " + position.coords.longitude);
    });
}

From

http://robertnyman.com/2010/03/15/geolocation-in-web-browsers-to-find-location-google-maps-examples/

Upvotes: 1

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