MapsService.js

angular.module('atlasApp').service('MapsService', function(
  	$scope, 
  	$http,
  	LocationProvider,
  	BusInfoProvider) {
  var MapsService = {};
  
  MapsService.initMap = function() {
    console.log('Initializing');
    var mapOptions = {
      zoom: 15,
      center: $scope.mapCenter,
      mapTypeId: google.maps.MapTypeId.ROADMAP,
      disableDefaultUI: true,
    };

    MapsService.mapCanvas = document.getElementById('map-canvas');

    MapsService.map = new google.maps.Map(
      MapService.mapCanvas,
      mapOptions
    );
  }
  
  MapsService.showMap = function() {
    MapsService.mapCanvas.hidden = false;
  }
  
  MapsService.hideMap = function() {
    MapsService.mapCanvas.hidden = true;
  }
  
  MapsService.plotMarker = function(lat, lng, name) {
    var position = new google.maps.LatLng(lat, lng);

    $scope.marker = new google.maps.Marker({
      position: position,
      map: $scope.map,
      title: name
    });
    
    return  position;
  };

  MapsService.setCenter = function(position) {
    MapsService.map.setCenter(position);
  };

  return {
    initMap: MapsService.initMap,
    showMap: MapsService.showMap,
    hideMap: MapsService.hideMap,
    plotMarker: MapsService.plotMarker,
    setCenter: MapsService.setCenter
  };
});

The benefit of structuring the Service like this is:

• You can refer to MapsService.instanceVariable explicitly instead of this.instanceVariable. this is ambiguous and could be referring to a different object (like in the case of an anonymous inner function).
• In the return statement on line 49, you only return the functions and objects that are public. So in this gist's example, we do not expose MapsService.mapCanvas so that the user of this service isn't able to mess with that object and accidentally destroy / change it.