Error Message: nil cannot be coerced into float

textbooks_controller.rb

def show
   
    @textbook = Textbook.find(params[:id])
    @this_user = User.find_by_id(session[:user_id])

      @textbook.user_textbook_statuses.each do |attribute|
      @map = Map.new(:to_location_id => attribute.user.location_id, :from_location_id => 
      @this_user.location_id)
      @from_address = @map.from_location.as_json(:only => [:latitude, :longitude])
      @to_address = @map.to_location.as_json(:only => [:latitude, :longitude])
      @distance = Haversine.distance(@from_address['latitude'],
                                     @from_address['longitude'], 
                                     @to_address['latitude'], 
                                     @to_address['longitude'])
      @map.update_attributes(:distance => @distance)
      @map.save
        
        locations = [ @from_address, @to_address ]
          new_locations = locations.map do |marker| { lng: marker['longitude'], lat: marker['latitude'] 
                                                    }
          end

      @map = [new_locations]
      @location = @map.to_json
                
        
    end