• 沒有找到結果。

Image-Based Navigation

在文檔中 行動導航之示意地圖應用 (頁 23-0)

Chapter 2 Related Works

2.2. Image-Based Navigation

Many researchers studied the use of the photos as navigation aids in a navigation

system. Beeharee and Steed [7] described a navigation system with geo-tagged photos.

Their navigation system comes with a map view with route line and navigation

instructions, a route tab with complete route instructions, and a viewer tab shows

photos along the route. This system was then tested with and without photos. Their

results indicate that the photos had shortened the time required to complete the

navigation task and helped the users to reorient themselves more easily. The

participants used the photos to make and confirm decisions.

Hile et al, [8] described a navigation system with online geo-tagged photos. This

system has two modes - a map mode and a landmark mode. The landmark mode

shows photos of landmarks with related navigation instructions. During the test, the

participants were required to walk a route using these two modes. The test participants

found the landmarks mode useful in intersections and they would use them again.

Chen et al. [9] described a system using route videos as navigation aids. This

system provides 360-degree panoramas videos around the pre-selected landmarks

near intersections. The system displays a map of the route with thumbnails of

landmarks and a video of the route with dot moving along the path indicating the

location of the video. In addition to this, a list of navigation instructions (written

instructions and thumbnails of landmarks) is also included. They performed a test to

compare the performance of a map with videos and a map with photos. The

participants were asked to familiarize themselves with route using either the video

map or the photo map. After finished the familiarization step, the participants were

then asked to perform a virtual drive of the same route and they were asked to make

decisions on where to turn at intersections. In general, the participants performed

better with the video maps - they needed to check for instructions less often.

These researches show that photos and videos of landmarks are useful navigation

aids [24]. This method is especially useful for decision making near the intersections

and the verification of navigation choices. It should not replace the map, but to be

provided as additional geospatial information.

Chapter 3

Requirement Analysis

In Chapter 2 several related studies for mobile navigation were inspected. By

investigating the design and development methods of these apps, the decision on the

type of methodology to use in this thesis was made. In order to deliver an effective

communication of geospatial information via geolocation apps, along with the support

of technology, the needs, desires, and limitations of the end users of such systems

must be given extensive attention during the design process. An approach

User-Centered Design (UCD) fulfills these requirements, and there are an increasing

number of geolocation apps using it in their design process. I selected UCD as the

overarching methodology for this thesis.

This chapter first provides an overview of the principles of UCD. It begins with a

discussion about usability, and then several user-centered approaches are introduced.

Following on from this is a more detailed discussion about the purpose, expectations,

and research strategies of UCD.

The second part describes how UCD applied in this research. In order to create

geolocation apps with high usability, the users for such systems must be defined first.

A requirement analysis was carried out, and the user profile for the target users that

this system focusing on was created. To gain an understanding of the user’s

requirements for a geolocation app, semi-structured interviews and field-based user

shadowing were conducted. The results from these observations are included at the

end.

3.1. Fundamentals of User-Centered Design

UCD is an approach used in computer systems design. Its purpose is to address

these fundamental questions: ‘How do I understand the user?’ and ‘How do I ensure

this understanding is reflected in my system?’ [10]. In order to create a usable and

successful final product, the design process positions the end user at the center to

ensure the user can easily use the system to meet his or her needs [11]. Vredenburg et

al. defines UCD as the practices of “the active involvement of users for a clear

understanding of user and task requirements, iterative design and evaluation, and a

multidisciplinary approach” [12]. The system does not require users to adapt their

behaviors to use; instead, it is designed to support its users’ existing behaviors.

The techniques and ideas of UCD came from the early works of Gould and

Lewis (1985) [11] and Norman and Draper (1986) [13]. At that time, Gould and

Lewis proposed and discussed three basic principles for this emerging field: (1) an

early focus on understanding users and their tasks; (2) empirical measurement of

prototype by representative users; and (3) an iterative cycle of design, test and

measure and redesign. In 1988 Norman [14] further elaborated UCD and he suggested

every good design should follow these four main principles:

1. Make it easy to determine what actions are possible at any moment.

2. Make things visible, including the conceptual model of the system, the

alternative actions, and the results of actions.

3. Make it easy to evaluate the current state of the system.

4. Follow natural mappings between intentions and the required actions;

between actions and the resulting effect; and between the information that is

visible and the interpretation of the system state.

In addition to this, Norman also suggested the following seven design rules are

essential to facilitate the designer’s tasks:

1. Use both knowledge in the world and knowledge in the head. This principle

is based on the theory of mental models. The designer has a conceptual

model about the system, and during the use the user also develops a mental

model explaining the operation of the system. For the system to succeed, the

designer’s model must match with the user’s mental model. However, the

designer does not talk directly to the user. The designer can only

communicate with the user through the "system image”. The system image

is the designer’s materialized mental model, such as the system’s

appearance, operation, or the manuals included with it. The designer must

ensure that the system image is consistent with his or her conceptual model.

2. Simplify the structure of tasks. Tasks should be simple. Avoid requiring

difficult actions like planning and problem solving in them. Consider the

limits of the user’s short-term memory (STM) and long-term memory

(LTM). On average the user is able to remember five to nine unrelated

things at a short time. Keep the task consistent and provide mental aids for

easy retrieval of information from LTM.

3. Make things visible: bridge the gulfs of execution and evaluation. Consider

Norman’s stages model of actions in Figure 3.1. The left side of the figure

(intention to act, sequence of actions, and execution of actions) is the

execution part. The user interface should provide information for the user to

decide which actions he or she should undertake. The right side of the figure

(perceiving the state of the world, interpreting the perception, and

evaluation of the perception) is the evaluation part. The user interface

should provide feed to show the user what can be done and what the results

are.

Figure 3.1 Norman’s stages model of actions.

4. Get the mappings right. A natural mapping that leads to immediate

understanding should be used. The representation of the control’s

functionality should be made with careful considerations of cultural

standards and physical analogies.

5. Exploit the power of constraints, both natural and artificial. Design the

system to make the user feel that there is only one action possible or logical

to do.

6. Design for error. Assume that the user will make errors. The system should

be designed to allow the users to recover from any possible error made.

7. When all else fails, standardize. Create a universal standard for things

cannot be explained in any logical or culturally determined way.

In 1999 an international standard ISO 13407 was release, entitled

‘Human-Centered Design Processes for Interactive Systems’, providing a

standardized description of UCD [15]. ISO 13407 provides guidance for achieving a

high level of usability through UCD actions and strategies. This standard describes an

iterative cycle of development composed of five main activities of UCD. Four of

these activities are performed iteratively until the outcome meets the initially set

objectives. Every UCD project should carry out these activities from the beginning.

These activities are listed below and presented in Figure 3.2:

1. Plan the human centered process.

2. Understand and specify the context of use.

3. Specify the user and organizational requirements.

4. Produce design solutions.

5. Evaluate designs against requirements.

Figure 3.2 The five main activities of UCD (adapted from ISO 13407 [15]).

ISO 13407 aims to provide general guidelines for UCD, the detailed description

about the research methods and techniques required to conduct these activities is not

included [16]. In fact, there are many research methods and techniques available for

UCD, with Table 3.1 presenting a selection of them, grouped by the four main

activities described above. The detailed discussion about each of these methods is not

within the scope of this thesis, instead, only the details of those been selected and

considered for this research will be included in below and following chapters.

Table 3.1 Research methods for UCD (adapted from [17, 18, 19, 21, 20]).

3.2. UCD Methodologies Applied in This Research

The main objective of this thesis is to design and evaluate a cartographic UI for

geolocation apps that supports the geospatial activities of a pedestrian user in

unfamiliar surroundings. In order to achieve high usability in such a system, UCD

methods should be carefully applied. As the first step, requirement analysis was

conducted to determine the user's needs, characteristics, context of use and

preferences. Methods like user profiling, interviewing existing users, and user

shadowing were used. Regarding traditional methods such as interviewing or

surveying can fail to gain deep understanding of the use context; a field-based user

shadowing was applied additionally to users during their actual trip in unfamiliar

environments.

The UCD-based plan of this research is presented in Figure 3.3. Following this

plan, the rest of this Chapter describes the Requirement Analysis stage, including user

profiling (Section 3.3), interview (Section 3.4), and field-based user shadowing

(Section 3.5).

Figure 3.3 The UCD-based plan of this research.

3.3. User Profiling

Understanding the target users of a system is critical in the UCD approach, and a

careful selection of a representative user group for the system to focus on is required.

Geolocation apps have a wide range of users in the general population. A survey was

conducted by GlobalWebIndex to determine the most used smartphone app in the

world. A list of smartphone apps were selected and presented to the survey

participants, and they were asked to answer the question “Which of the following

mobile applications have you used in the past month?” Not surprisingly, Google Maps,

a typical geolocation app, is the most popular mobile apps in the world, with over

54% smartphone owners using at least once during the month of August 2013 [25].

Since it would be infeasible to include the entire population of the potential users, the

target user population is limited to a smaller and manageable size which only focusing

on certain types of geolocation apps. This is used as an initial description of the users

to create the user profile.

To identify a meaningful geolocation apps area to concentrate on, I conducted a

review of related researches and commercial implementations. The result shows that

the majority of both the research projects and the commercial geolocation apps

targeted on tourism and travel type applications. As tourism information is commonly

geospatial, there is a large scope for exploring usable representations of it. A selection

of these commercial travel-based geolocation apps are presented in Table 3.2. With all

these factors, this thesis will focus on the area ‘travel and navigation’ of the

geolocation apps.

Table 3.2 Examples of existing geolocation apps.

User profiling defines the use contexts, characteristics and preferences of the

potential end users who are going to use the cartographic interface. In addition to the

general profile of the users of interest in this research given in Chapter 1, a more

detailed description of the characteristics of the intended users is shown in Table 3.3.

Table 3.3 Characteristics of the potential target users group.

3.4. Interview

To further understand the user requirements and define the design goals,

semi-structured interviews were conducted. The interviews aim to assess how a user

plan and conduct their trip in an unfamiliar environment. A typical scenario can be a

traveller arriving by train in an unfamiliar city - as he or she exits the underground

railway station, it may not be easy for such a traveller to immediately know where he

or she is and which way to go. The orientation question of “where am I?” must be

addressed first before resolving all other geospatial problems such as how to reach a

desired destination from the current location.

Based on the objective of this thesis and the related works described in previous

 What kinds of geospatial information are required by the travelers when

they first arrive in an unfamiliar area?

 In which way do users use the mobile map to navigate?

 Do users find street photos and voice directions helpful?

 What information on the mobile maps and the mental maps of users are

important for navigation and wayfinding?

 Do users find it difficult to relate the mobile maps with the real world

surroundings?

 How often and when do users feel themselves lost orientation and what is

the reason for that?

 Do users find landmarks helpful?

 Do users have problems with the zooming and panning techniques in

mobile maps?

The objective of the interview is to obtain a more clear understanding about the

user needs for pedestrian navigation and wayfinding. The findings from these

interviews were later used in the design of the prototype.

3.4.1 Participants

As presented in the previously created user profile (see Table 3.3), the interview

participants should represent a particular group of geolocation app users who visit an

unfamiliar city. 10 participants are recruited to participate in this study. 5 of the

participants are female and 5 are male. Few of them are foreigners. The average age is

32.4, with a minimum of 20 and maximum of 50. All participants owned touch-screen

smartphones and had used a geolocation app like Google Maps before. However, they

may have different levels of experience and knowledge with mobile devices, digital

maps, cartography, and navigation and wayfinding techniques. Table 3.4 and Table 3.5

present the profiles of these participants and their experiences with different fields

related to this study.

Table 3.4 Profiles of the interview participants.

Table 3.5 Interview participants’ experiences in fields related to this study.

3.4.2 Findings

I discovered common user behaviors from the interviews. In general, the

majority of participants plan their trips using a computer, tablet, or guidebook at home

before they travel to an unfamiliar city, and the rest of the participants only do this if

the preparation time allows. Most of them use digital maps on the screen of a

computer or tablet, and some use the printed paper map on the guidebook. They use

the map to find POIs and the routes from the public transportation stations to their

hotels. In order to learn about all the best POIs to visit, they search on the web, find

information on travel websites like TripAdvisor or Lonely Planet, or ask others who

have already been to the city for recommendations. To prepare for the actual

navigation, they ask friends who have visited the city about important landmarks that

can help them to stay oriented. They also look for the street photos of the POIs for the

reason that it could help them to recognize the places more easily.

Upon their arrival to the unfamiliar city, some participants use paper maps to do

the navigation, some use the navigation apps on their mobile phones. Four of the

participants (P1, P4, P5, P9) find using the paper maps difficult, they sometimes still

get lost in the unfamiliar environment. Most participants find the mobile navigation

system more helpful than paper maps. They only use the paper maps when they have

no access to a mobile navigation system.

In the case of using a mobile navigation system, the participants use the mobile

phones to search for the desired destination on the go. They often use mobile devices

as a tool to figure out the next destination. For example, at restaurant, they search for

good coffee shops to go after the meal. If they are at the hotel, they commonly look

for the navigation guidance on a computer or tablet before heading out. The

destination often described as landmarks, places, or POIs. Once decided on a

destination, three of the participants start the turn-by-turn navigation immediately; the

other seven of the participants preview the navigation instructions and the route on

map before they start. Street images and landmarks are important at the decision

points along the calculated route, such as the final destination and the turning points

where the moving direction changes. If panoramic street images are provided, they

rotate the street images from different viewing angles to look for business logos and

obvious landmarks. They find the street images toward their point of view more

useful and meaningful than street images from other viewing angles.

The participants find the details available on the street map much less important;

they normally concentrate more on the highlighted route that represents the directions

for turn-by-turn navigation. They look for street names, landmarks, and the

intersections before the next turning point to make sure that they are aware of the turn

beforehand. This inspired me to remove unnecessary map details in the design of

TopoNav.

Sometimes the participants still get lost, even with the help of maps and mobile

navigation system. When this happens, if using a paper map, six of them try to find

their way by using the street name information or landmarks nearby to relocate

themselves on the map; if using a mobile navigation system, the system commonly

would recalculate the route to destination and show its user how to get back to the

correct path.

3.5. User Shadowing

In order to complement the findings from the interview and better understand the

context of use, I additionally shadowed users during their actual trips. As presented in

Table 3.2, there are already many geolocation apps available in the market.

Considering the equipment available in this requirement analysis, only those

applications compatible with iOS 7.1 and Android 4.4 were investigated.

For this study, an existing geolocation app was selected for the participants to

perform real world navigation tasks in the context of a traveller to an unfamiliar city.

The application was selected based on the following features:

 Covers the study area (Taipei City)

 Availabilities to the participants and researchers

 Turn-by-turn navigation

 Voice directions

 Street images

 Zooming and panning functions

Google Maps (Figure 3.4) was selected for that it supports all the features listed

above and is the most popular mobile application currently available.

above and is the most popular mobile application currently available.

在文檔中 行動導航之示意地圖應用 (頁 23-0)