navigator.geolocation.getAccuratePosition

navigator.geolocation.getAccuratePosition

// navigator.geolocation.getAccuratePosition() is an improved version of navigator.geolocation.getCurrentPosition()
// 
// getAccuratePosition() is designed and tested for iOS.
//
// The problem with getCurrentPosition() is that it returns an inaccurate position even with "enableHighAccuracy" enabled.
// The problem with watchPosition() is that it calls the success handler every second, and it is resource-intensive.
// 
// getAccuratePosition() calls the callback only once, but uses watchLocation() internally to obtain a position that meets your accuracy needs.
// If the timeout is exceeded before a position meeting your accuracy is needed, the best position is returned to the
// success callback, and the error callback does not fire. If you really care about accuracy, you should check it
// yourself in your success callback.
//
// getAccuratePosition() has the same signature as getCurrentPosition() and watchPosition()
//   (see http://dev.w3.org/geo/api/spec-source.html#get-current-position)
// BUT allows specification of opts.accuracy, which is treated as a minium required accuracy (in meters)
// If no accuracy is specified, it defaults to 1000m if enableHighAccuracy=false, else 50m.
navigator.geolocation.getAccuratePosition = function(successF, errorF, opts)
{  
    opts.accuracy = opts.accuracy || (opts.enableHighAccuracy ? 50 : 1000);
    opts.timeout = opts.timeout || 10;
   
    var watcher;
    var bestPosition = {};
    var initialTimeMS = (new Date()).getTime();
   
    var mySuccessF = function(position) {
        console.log('watchPosition update: ' + $.toJSON(position));
        bestPosition = position;
        if (position.coords.accuracy <= opts.accuracy || ((new Date()).getTime() - initialTimeMS) > opts.timeout)
        {
            navigator.geolocation.clearWatch(watcher);
            successF(bestPosition);
        }
    };
    var myErrorF = function(error) {
        navigator.geolocation.clearWatch(watcher);     
        errorF(error);
    };
    watcher = navigator.geolocation.watchPosition(mySuccessF, myErrorF, opts);
};

Cool, thanks! Glad it was helpful.

…

On Dec 5, 2011, at 9:12 PM, gorelog wrote: Hello, I want to thank you for sharing this. I've been struggling to get accurate positioning and I'm hoping this will help. I noticed that the bestPosition returned was always the last one generated, so I added a little check before passing the current position to the bestPosition. https://gist.github.com/1436289 Thanks again. --- Reply to this email directly or view it on GitHub: https://gist.github.com/510278