Unable to set a class var in $http callback

In the example below I am trying to set a variable defined in the below service, in the success callback. I am unable to set the var authMap in the service. What is happening here and how do I do it?

app.service("authorization", ['$http', function($http){
  this.authMap = [];
  $http.get('/authmap').success(function(data){this.authMap = data});

}]);

A new scope is created in your anonymous callback function, so this is different.
You could do something like:

app.service("authorization", ['$http', function($http){
  this.authMap = [];
  var that = this;
  $http.get('/authmap').success(function(data){ that.authMap = data });
}]);