Introduction

1.1 Overview

Nowadays, it becomes more and more popular to buy airline tickets through online travel agent. People enjoy buying airline tickets online because of the convenience brought by the Internet. Many travel sites, such as Expedia.com, Travelocity.com and Yahoo's Travel, provide services which help travelers find airline tickets for their travel plans. In addition to providing the same services that a traditional airline ticket booking system would provide, these websites provide enhanced services such as searching through a list of possible flights according to a user's constraints.  

      Figure1.1 Flight Information from expedia.com

      Figure1.2 Flight Information from travel.yahoo.com

       Figure1.3 Flight Information from travelocity.com

However, there is still some room for further improvement on their user interfaces. For example, one unnoticed design problem you may be amazed is nearly all of these websites display information of flight schedule by a textual, tabular format, rather than a graphical format commonly used in modern user interface. Tabular format of flight schedule is inherited from traditional character-based format for a flight schedule seen in airports. It has been used for many years, and no one complains about its effectiveness. Nevertheless, when the same format is used on the web pages, some researchers begin to doubt whether it is the most effective means of presentation, and argue that a graphical presentation can be more effective than a tabular presentation[2, 3, 13].

This project tried to verify this claim by proposing a visual display method called Flight-Lines, which shows each schedule of flight by a line segment. Flight-Lines is compared with Fare-Finder (Travelocity.com), a popular online airline tickets reservation system which displays the information in a tabular format. In the Flight-Lines, the length of a line segment represents the flight time, and the thickness represents the cost of the flight. The thicker the line segment, the more expensive the flight. The hypothesis is that Flight-Lines is better than Fare-Finder in presenting flight schedules, since Flight-Lines uses consistent visual displays by which users can utilize the cues they are familiar with such as proximity, overlapping and color. On the other hand, Flight-Lines can establish a good mapping between display of information and user's conceptual model of the information.

This experiment is designed to prove or disprove the hypothesis that Flight-Lines has better performance than Fare-Finder. First, the literature survey of this topic is presented in order to gain a deeper understanding of its previous research. Second, the experimental procedure and materials for the experiment is given. Afterward, the collected data is then analyzed by statistical methods such as t-test to see whether the experimental result supports or denies our hypothesis. Finally, the report concludes by giving suggestions for future study.

1.2 Background Survey

The survey is divided into two parts. The first part is about the websites of airline ticket reservations on the Internet and their presentation methods of flight scheduling. The second part is about past and present researches on timeline, a chonological display method.

1.2.1 Tools for Finding Airline Ticket

As mentioned before, many travel sites, such as Expedia.com, Travelocity.com and Yahoo's Travel, sell airline tickets on the Internet. These sites allow users to enter their departure and arrival places, and the departing and returning times for a round-trip flight, Then, all possible airline tickets that match the criteria will be displayed. Some of these sites also provide advanced search capabilities in which users can enter more constraints or even construct their own flight schedule. A list of airline tickets is usually displayed in textual and tabular format and sorted by the flights' prices. Users have to scan through the list to choose an airline ticket. They can load another list by changing the criteria. As far as we know, no travel site presents the list in a graphical format.

Only few research projects focus on investigating the method for visualizing airline flight schedules. Casner and Larkin[2] discussed the visualization of flight schedules for a single day, and argue that graphical presentations are more effective than tabular ones. BOZ[3], an automated graphic design and presentation tool, has been used to to design graphic presentations of airline schedule information to support five different airline reservation tasks. FareBrowser[13] is an interactive tool for finding and comparing airfares using a zoomable timeline with features such as zooming, details on demand and dynamic filtering to quickly focus on the best available fare. It presents an overview of available flight combinations for a specified time period. The user can zoom in to reveal additional details about the flight. Furthermore, users can interactively filter out the flights that do not meet the user's constraints. This study compared FareBrowser with Travelocity's FareFinder, a text based search tool. The result of the experiment suggests that novices find the simple menu-driven approach in Travelocity's Fare Finder easier to understand, but experienced users can perform complicated tasks more efficiently using FareBrowser.

1.2.2 Timeline

Many researchers have investigated methods for visualization of temporal data[4, 7, 1], and most of them suggest that chronological layout of the data such as in a timeline is a common and effective mean to visualize temporal data[15]. We often see that a timeline is used to present the historical development of an episode in the news and in other mass media. In project management, Gantt charts and PERT charts are typical examples of timelines in which the duration and type of tasks in the project are displayed. Some software tools such as Microsoft Project use these charts as their primary interface. Temporal-data visualization appears in systems for editing video data, composing music, and preparing animations[14]. A timeline is one of the fundamental components for the interfaces of these systems. Several generic visual programming controls of a timeline such as those developed by MediaCalc and V_Graph are available, and these controls are mainly used for developing interactive-multimedia authoring system.

The recent advance of timeline is on interactive timeline. Many researchers argue that interactive timelines, which employ techniques such as zooming, filtering, searching and details-on-demand, have many additional advantages over static timelines. Interactive timelines are found in LifeLines[10, 12, 8], a general visualization tool for personal histories. LifeLines applied multiple timeline representations to personal histories such as medical records. Its features such as horizontal and vertical zooming, focusing, and filtering enable users to represent complex histories. Lifelines supports exploration as well. By clicking a point on a timeline users can get detailed information about that point in time. Lifelines has been used to display the history records of youths for the Maryland Department of Juvenile Justice[10, 8], medical patient records[10, 12, 11, 9] and legal case histories[5]. R. B. Allen [1] suggested a number of ways the interactive timeline interface could enhance traditional paper timelines for information systems. R. L. Kullberg[6] devised and experimented a dynamic, three-dimensional timespace for historical information, based on conventional static, two-dimensional timeline.