d3.csv(locations, function(ldata){
    d3.csv(tripadvisor, function(tdata){
        for(i = 0; i< tdata.length; i++){
           var l = tdata[i];
           var j = ldata[l.locationID-1];
           var id = l.locationID ;
           if(id in user_ratings){
              user_ratings[id].evaluator.push[l.evaluator];
              user_ratings.id.rating.push [l.rating];
           } else{
              user_ratings.id = {};
              user_ratings.id.evaluator = [l.evaluator];
              user_ratings.id.rating = [l.rating];
           }
         }
     })
});