Develop Reference

Use js variable in api request

I'm building an app where i want to use the users location in the api request.
I fetch the user position with
if (navigator.geolocation) {
navigator.geolocation.getCurrentPosition(successFunction, errorFunction);
} else {
alert('It seems like Geolocation, which is required for this page, is not enabled in your browser. Please use a browser which supports it.');
}
function successFunction(position) {
var lat = position.coords.latitude;
var long = position.coords.longitude;
console.log('Your latitude is :'+lat+' and longitude is '+long);
}
I then need to use the lat and long variables in the api call render(<Main source="https://api.darksky.net/forecast/[key]/[latitude],[longitude]"/>, document.getElementById('app'));
I haven't been able to figure this out since i obviously can't just put the variable in the url

Check if user device's GPS is on

I am developing an app using jQuery Mobile with PHP. I am not using Phonegap or other frameworks. I need to find user's geolocation. If user device's GPS is off, then I cant get a location. now I need to find user device's GPS is on or off.
this is what i using now.
function getLocation() {
if (navigator.geolocation) {
navigator.geolocation.getCurrentPosition(showPosition);
} else {
x.innerHTML = "Geolocation is not supported by this browser.";
}
}
function showPosition(position) {
var lat=position.coords.latitude;
var long=position.coords.longitude;
}

You can call this function on load
// Function to get location
function getLocation(){
navigator.geolocation.getCurrentPosition(function (pos) {
var lat = pos.coords.latitude;
var lng = pos.coords.longitude;
if (lat == null) {
alert("GPS not activated!");
} else {
alert("Latitude: "+ lat + " , Longitude: " + lng );
}
});
}

There is no way to check if the device has a GPS module or if it has it enabled through the browser's API. Your laptop will, for example, try to estimate the position based on the IP address with very poor accuracy.
You can, however, use a trick that will likely be good enough for many applications: instead of using the getCurrentPosition(), use the watchPosition() function with an options object { enableHighAccuracy: true } and set a threshold of accuracy that the measurement has to reach for you to accept it as most likely a result based on the GPS module.
What happens when you start to listen to the watchPosition() with enableHighAccuracy set to true is that if GPS module is available, the API will let it know that you're trying to get a measurement and after up to a few seconds the accuracy distance will go from very high (often thousands of meters - based on IP address, cell tower triangulation, etc.) to a very low (few meters - based on the GPS) and that means that the GPS kicked in. If the accuracy stays at hundreds or thousands of meters, it probably means that there is no GPS module available.
Here's the documentation for the GeolocationCoordinates object (the result within the callback passed to the watchPosition()) which comes with the accuracy field. I wrote a longer post that also contains a code snippet showing how I use the API within React.

I just solved this one. I am using:
navigator.geolocation.getCurrentPosition(successCallback, errorCallback, {maximumAge: 60000});
In the successCallback i written the codes for what it should do once I got the positions and in the error callback i wrote a simple alert message to prompt the user to turn the GPS on.

I Implemented This In Real World Project
KMaps-API GPS.js
<script>
function getLocationw() {
if (navigator.geolocation) {
navigator.geolocation.getCurrentPosition(showPositionw);
} else {
x.innerHTML = "Something Is Wrong";
}
}
function showPositionw(position) {
lat = position.coords.latitude;
if(lat != null){
document.write('<center><div class="alert alert-info" role="alert"> Please Turn On Your GPS </div></center>')
}
}
getLocationw();
</script>

constantly get the current position of a mobile phone

I would like to know how I can constantly get the current position of a mobile phone (latitude and longitude) using JavaScript.
Basically, when the phone is in a certain area I would like to start a timer. If the phone gets out of a certain area, the timer needs to stop. To do that, I need to constantly check each second, if the user is still in that area.
This is the code that I'm using to get the user's position:
if (navigator.geolocation){
navigator.geolocation.getCurrentPosition(showPosition);
}else{
alert("Geolocation is not supported by this browser.");
}
function showPosition(position) {
setInterval(function(){
lng = position.coords.longitude;
lat = position.coords.latitude;
geo.innerHTML="Latitude: " + lat +"<br>Longitude:" + lng;
myXhr.open("get", "Geo.php?lat="+lat+"&lng="+lng, true);
myXhr.send();}, 1000);
}
Moreover, when I tested it on my phone and I moved around a room, the coordinates did not change at all.
Thanks a lot for helping me out!

Get coordinates from Hardware GPS

I've found a lot of questions about GPS Coordinates but not one that confirms using the mobile hardware GPS instead of Web GPS like geoLocation and such like.
My actual method:
I'm using navigator.geolocation.getCurrentPosition(), the Lat/Long comes from the Web, here's the code:
function getGPS(funcCallBack)
{
if (navigator.geolocation)
{
var timeoutVal = getCookie("GPSTimeout");
navigator.geolocation.getCurrentPosition(sucess
,error
,{enableHighAccuracy: true
,timeout: timeoutVal
,maximumAge: 0}
);
}
else{
alert('GPS is turned off, or was not possible to find it. Now, doing the login without localization.');
window.gpsLat = 0;
window.gpsLng = 0;
window.gpsAcc = 0;
funcCallBack();
}
function sucess(position) //sucess
{
window.gpsLat = position.coords.latitude;
window.gpsLng = position.coords.longitude;
window.gpsAcc = position.coords.accuracy;
funcCallBack();
}
function error() //error
{
window.gpsLat = 0;
window.gpsLng = 0;
window.gpsAcc = 0;
funcCallBack();
}
}
My problem:
Sometimes when I do the login I am not getting the GPS Coordinates (they come 0) and sometimes I am getting coordinates with more than 2,000 Accuracy (that is not precise).
By the way, I am testing the GPS on a data internet service, when I do use a Wi-Fi connection it works perfectly with less than 100 Accuracy.
Details:
Maybe you are complaining about:
timeoutVal: it is a cookie with the number 5000 inside it.
funcCallBack: it is a function that continues the login operation.
window.gpsLat: it is a global var containing the Latitude value got from the geoLocation.
window.gpsLng: it is a global var containing the Longitude value got from the geoLocation.
window.gpsAcc: it is a global var containing the Accuracy value got from the geoLocation.
What do I want?
I want a solution in JavaScript or PHP that can get coordinates from the mobile hardware device, the Native GPS, not the geolocation, and when the Native GPS is turned off, ask the user to turn it on.

You should get the location with javascript not PHP. PHP is only capable of doing an IP lookup which is the least accurate method for determining location.
The way navigator.geolocation.getCurrentPosition() works is it uses the most accurate data currently available. In the case of a mobile device it will use GPS first if enabled, then wi-fi.
If native GPS is enabled javascript will access that data instead of the wi-fi data, but there is no way of preventing a check against the wi-fi data if the GPS data isn't available.
Your best solution is to check the accuracy field and if it's not within a range you're happy with ask the user to enable GPS.
Alternatively if you're building a hybrid app, most of the frameworks (PhoneGap .etc.) have APIs to query the device GPS directly. Use PhoneGap to Check if GPS is enabled

Geolocation API does not expose a direct way to check whether GPS is on or off, but you can catch the errors of geolocation and base on error type can draw conclusions from there.
E.g. POSITION_UNAVAILABLE (2) if the network is down or the positioning satellites can’t be contacted.
But its not sure short way you have to handle some conditions!
I will suggest use watchPostion { i agree its meant to watch and continuous to locate position} u can keep it on and if GPS throw the error u can prompt custom alert to make user turn on the GPS device/wifi/internet .. and if its come to success callback u can clear the watch.
var watch =null;
function success(position)
{
var lat = position.coords.latitude;
var lon= position.coords.longitude;
if (watch != null )
/*Need to take care .. as maybe there is no gps and user
want it off so keep attempt 3 times or some kind a way out otherwise it will
infinite loop */
{
navigator.geolocation.clearWatch(watch);
watch = null;
}
}
function getLatLon()
{
var geolocOK = ("geolocation" in navigator);
if ( geolocOK )
{
var option = {enableHighAccuracy:true, maximumAge: 0,timeout:10000 };
watch = navigator.geolocation.watchPosition(success, fails, option);
}
else {
//disable the current location?
}
}
function fails()
{
alert("please turn on the GPS !");
}
getLatLon();

Center Google Map Based on geocoded IP

Basically whenever someones opens up my (Google) map I want it default to their approximate location.
Is there an easy way to do it with Google's API or do I have to write a custom code (this is python based app)?

You can use Google API's built-in ClientLocation object:
if (GBrowserIsCompatible())
{
var map = new google.maps.Map2(document.getElementById("mapdiv"));
if (google.loader.ClientLocation)
{
var center = new google.maps.LatLng(
google.loader.ClientLocation.latitude,
google.loader.ClientLocation.longitude
);
var zoom = 8;
map.setCenter(center, zoom);
}
}

Check out http://www.ipinfodb.com/. You can get a latitude and longitude value by passing their services an IP address. I did something recently where I created a simple service that grabbed the current IP address and then passed it to the service ("api/location/city" is just a service that curls the ipinfodb service). Using jquery:
$.get("api/location/city", null, function(data, textStatus)
{
if (data != null)
{
if (data.Status == "OK")
{
var lat = parseFloat(data.Latitude);
var lng = parseFloat(data.Longitude);
$.setCenter(lat, lng, $.settings.defaultCityZoom);
manager = new MarkerManager(map, {trackMarkers : true });
var e = $.createUserMarker(map.getCenter());
e.bindInfoWindowHtml($("#marker-content-event").html());
var m = [];
m.push(e);
// map.addOverlay(e);
manager.addMarkers(m, 10);
manager.refresh();
}
else
{
$.setCenter($.settings.defaultLat, $.settings.defaultLng, $.settings.defaultZoom);
}
}
}, "json");
The key here is this line:
$.setCenter(lat, lng, $.settings.defaultCityZoom);
Just setting the center to the lat/lng of the result of the service call.

Per the docs, just map.setCenter(new GLatLng(37.4419, -122.1419), 13); or whatever other coordinates. Doing it in the page's Javascript is normally preferred.
If you mean translating an IP to lat and long, I don't think the Google API supports that, but there are other web services that do, such as maxmind, hostip, and many, many others. I don't know which one(s) to recommend -- try out a few, would be my suggestion!

If the user uses FireFox 3.5/google gears, you can retrieve the lat and lng from the browser itself.
You'll find details on another stackoverflow post here

IP Address Geocoding API for Google Maps: http://web3o.blogspot.com/2011/06/ip-address-geocoding-api-for-google.html