500px.js

 $(document).ready(function () {
   var $loginBtn = $('#login');
   var $signInView = $('.sign-in-view');
   var $imageResultsView = $('.image-results-view');

   // initialize the SDK with our API key
  _500px.init({
    sdk_key: '8626d07001b7482e7707a6248a3b28bcaf22fd23'
  });

  _500px.getAuthorizationStatus(function (status) {
    if (status == 'authorized') {
      load()
    }
  });

  $loginBtn.on('click', function() {
    _500px.login(function (status) {
      if(status == 'authorized') {
        load();
      } else {
        // not authorized
      }
    });
  });

  function load() {

    $signInView.hide();
    $imageResultsView.show();

    if(navigator.geolocation) {
      navigator.geolocation.getCurrentPosition(function(position) {
        var radius = 50;
        var geo = position.coords.latitude +
                  ',' +
                  position.coords.longitude +
                  ',' +
                  radius +
                  'mi';

        console.log(geo);

        _500px.api('/photos/search', {geo: geo}, function(response) {
          console.log(response);
        });
      });
    } else {
      console.warn('browser doesnt support geolocation');
    }
  }
 });