Chapter 3 Requirement Analysis
3.6. Results of the Requirement Analysis
This section summarizes the findings from the semi-structured interviews and the
user shadowing observations to answer the questions presented in Section 3.4.
Only current route matters - all participants in the interview find most details
on the traditional street map unimportant. During the shadowing observation,
seven of the participants pan and zoom the map to see the street names along the
calculated route. These results indicate that current route has an overwhelming
importance over other parts on the street map.
Identifying the destination and turning points is necessary - in the interview,
all participants report street images and landmarks helpful at the destination and
turning points. However, when I shadowed travelers, Street View was not used.
The reason might be that there is no Street View provided for turn-by-turn
navigation on the current mobile version of Google Maps. The participants are
discussing their experience from desktop Street View in the interview.
Fragmented attention to mobile devices while walking - I observed that the
voice directions are not used, and people often just holding the mobile device in
hand or keeping it in the pocket during the trip. They only interact with the
mobile device when they feet lost. From both the interview and the shadowing
observation, I learned that most participants often preview the route before they
start to navigate. It shows that route preview is a usable and effective navigation
tool for travelers.
Chapter 4
Implementation and Evaluation
Based on the user requirements collected, I found that generally the travelers
consider the calculated route significantly more important, look for an intuitive way to
identify the decision points such as destination and turning points, and only pay
fragmented attention to the mobile device while walking. I argue that existing
solutions such as digital street maps and turn-by-turn navigation systems are not the
best way to guide a pedestrian from A to B. To provide an alternative approach to this
problem, I propose TopoNav: a pedestrian navigation system on a mobile device that
uses a topological map.
4.1. Design Implications from Requirements Analysis
With the requirements analysis, I observed that travelers look for an easy way to
learn critical information about the calculated route. Instead of providing all the
unneeded details on a street map, the following describes the properties that a
pedestrian navigation system on mobile devices should follow:
Focus on the calculated route - I found that the majority of the travelers ignore
most details on the street map before and during their trip. To obtain a quick
overview of the calculated route, travelers typically look for navigation cues such
as street names and landmarks along the route. Although the calculated route is
highlighted in a typical navigation system, I believe more details on the map can
be omitted to keep users away from distractions. The system should try to focus
on providing only the information required by travelers in the first place, and a
topological map might be well suited for this purpose.
Identify the destination and turning points - from the observation, identifying
the destination and turning points are critical for any travelers who wish to
navigate to a destination. In an unfamiliar environment, travellers need to be
notified in advance when approaching a turning point or the destination along the
route. They typically look for street names, landmarks, and street images around
these locations. Therefore, the system should provide the possibility for its users
to quickly and conveniently identify these decision points.
Represent information in a clear and simple way - due to the limited display
size, modern mobile devices cannot display all the required information at once.
The observed travelers often need to repeatedly pan and zoom the map to get a
complete overview of the calculated route. Additionally, it requires travelers to
change their focus away from the activities in the real world to interact with their
mobile phones. This can be dangerous if the user interface is cluttered with
information and demands the user’s full attention. In order to provide a higher
usability while users being mobile, I assume the system should provide a user
interface that remains simple and requires minimum interactions.
No constant attention to the mobile screen is required - in the navigation
scenarios, the observed participants are constantly on the go. Their main focus is
not always on the mobile devices and they are often busy at doing something else.
While walking, they rarely check the map and never use the voice directions on
the mobile devices. Considering their short attention spans, the system should
not require the users to frequently to interact with.
Reduce cognitive burden - to navigate with a 2D map, it requires travelers to
relate the information provided by the map to their physical environment. The
travelers do not have to worry about the relationship between the map and the
surroundings with voice directions. However, I found that no participants use it
in navigation regardless of it being provided during the observation. The reason
might be that it requires users to be actively attentive to the system, and
sometimes the users may not be prepared for directions (e.g. chatting with
friends). The system should provide any kind of navigation aids that helps to
reduce the cognitive load from users.
4.2. Implementation
The TopoNav prototype is implemented on iOS and runs on a standard Apple
iPhone 5 (iOS version 7.1). With a 13 GHz dual core A6 processor, the device
provides smooth operations over existing map applications. It has built in GPS
receiver to determine the latitude and longitude coordinates of one’s current position.
Also a digital compass has been integrated to the device to obtain the direction that
one is facing, which can be useful when used with a map application. A web-based
solution is adopted which uses Google Map API to obtain geographic data for
TopoNav. Conceptually, this application can be ported to other platforms which have
built in GPS receivers and digital compasses.
With the user requirements collected I take the next step. The goal of TopoNav is
to investigate the usage of topological map in mobile navigation. I implemented
TopoNav along with following design concepts.
Quick access to the desired destination - in order to help travelers find the
destination they look for as soon as possible, I try to make the selection of the
destination in TopoNav intuitive. The destination can be searched via text-entry,
similar to traveler’s previous experience with existing map applications such as
Google Maps or Nokia Maps.
There are two rationales behind this design decision. First, the observed travelers
all have experience with existing map applications. Users often create mental
models before they start use software and these mental models come from their
previous experience with similar software. These mental models are later
referred by the users to predict what they should do with the software. Second,
instead of general areas, observed travelers often select specific business or
address as their destination. Therefore, I assume that travelers would prefer to
have text-entry search in the navigation system.
The screenshots in Figure 4.1 show the implementation of this design concept.
There is a textbox in the view. While typing the name of the business, the address
of the place, or the category that the user is looking for, a list of options matching
the text entered displays below the textbox. Tapping one of the options on the list
will select the POI as the destination, and then the system will launch route
preview from the user’s current location to the selected POI.
Figure 4.1 Screenshots of TopoNav.
Simplify map to focus on the calculated route - in order to make the TopoNav
easy to use on mobile devices, I eliminate as many unnecessary information on
the map as possible. Instead of using a traditional 2D street map, I choose to
represent the calculated route on a topological map.
From the requirement studies, the observed travelers often only looked for
information along the calculated route to destination. If travelers would like to
know how to get to the destination, they only require a general overview along
the route as guidance. It is not necessary to precisely represent every detail in the
area; instead, providing a rough outline of the calculated route in the map is
mandatory. In addition to this, simplifying the map can help to overcome the
limitations of the small screen on mobile devices. The resulting map should be
easier and clearer to read.
The user interface of the navigation view (Figure 4.1) is implemented following
this concept. Once the user selected a destination, the system calculates the route
and displays it on the map. Only the route to destination is drawn on the map,
other details, such as streets in the area, are omitted. By default, the map is at the
zoom level that the complete route can be displayed at once on the mobile device.
Based on the positioning methods available on the device, such as GPS, a blue
dot is displayed on the map to indicate the user’s current location. A red pin is
displayed on the map to indicate the destination.
The route is composited by multiple line segments. Each line segment represents
a street or road along the route. Naively placing every street name label along the
route might be problematic - labels might overlap with each other excessively,
and the resulting map is difficult or even impossible to read. To overcome this
label placement problem, labels are placed in order of their importance. Major
roads and the coming up street in next step are assigned with higher priorities. If
needed, a street name label is rotated and resized before placing beside its
corresponding line segment.
Identify turning points and destination for orientation - to provide orientation
support, keeping the users aware of the turning points and destination is critical
in a turn-by-turn navigation system. Therefore, the TopoNav prototype is
designed to help users effortlessly identify these special locations along the
route.
In order to reduce the cognitive load from users, I choose to use navigation aids
such as photographs and written instructions. On the top of the screen, there are
the navigation instructions that describe what the user should do at next turning
point (for example, turn right onto Robson Street). A street image towards the
traveler’s point of view at the next turning point is displayed underneath the
topological map. By tapping the toolbar at the bottom of the screen, the system
displays a list view of all written directions and street images, which lets the user
browse through the list for a quick summary of the route and faster switching
between the steps. In addition to this, landmarks near the turning points and
destination are displayed on the map.
Before the actual navigation starts, users can choose to preview the calculated
route. By default, the starting point is selected and the corresponding street
image and navigation instructions are displayed on the screen. As shown in
figure 4.2, gestures like swipe left and swipe right are used to select previous
step and next step on the route. As the selected step changes, the street image and
navigation instructions on screen change too. In order to differentiate the selected
line segment from the rest of lines along the route, the selected line segment is
highlighted in black color, and the rest of the route is in green color.
To minimize the downloading load required during the actual navigation, the
system pre-fetches all the street images in background after a destination has
been selected. The rationale behind this is the system’s user experience and
performance in the actual navigation can benefits from preloading images,
speeding up image load time.
4.3. Evaluation
Once the development for TopoNav prototype finished, a field-based evaluation
of its design by real world users was conducted. The usability of the prototype was
investigated to ensure that the user requirements had been met. The aim of these
usability tests was to gather user feedbacks for the cartographic interface and
determine where in the implementation need to be improved and refined. Based on the
results obtained from these tests, the usability of prototype for the target user group
can be optimized. This section describes the usability testing of TopoNav, starting
with a selection of testing methodology and the execution of these evaluation
techniques (Section 4.3.1), and then presents an analysis of the findings (Section
4.3.8).
4.3.1. Testing Methodology
There are different UCD techniques (empirical or inspection) available for
conducting a usability test [19]. Empirical methodology provides more user
involvement; the data was collected through the observations of target users
interacting with the prototype to achieve certain appointed tasks. Conversely, the
inspection method is generally performed with minimal user involvement; it only
relies on usability experts, developers, or designers to identify usability problems.
Since the objective of this thesis is to design a highly usable cartographic interface for
the target users, empirical methodology was considered to be more suitable. Only the
empirical methodology was used in this study.
Field-based observation was used to investigate the possible usability problems
of the prototype under real world conditions. As it is important to understand the
participants’ thoughts such as their intentions and expectations while they performing
the specified tasks, the technique think-aloud protocol was applied.
The purpose of test should be explained in detail to the participants before it
starts. The briefing must be made clear to them that it is the usability of the prototype
to be evaluated, not their abilities or capabilities. It is important to encourage the
participants to provide any positive or negative feedbacks about the prototype.
4.3.2. Test Tasks and Scenarios
A set of tasks was developed for the participants to perform during the evaluation
sessions. These tasks were formulated based on the general scenario of navigation
from a starting point to an unfamiliar destination. It is important for the tasks to
represent as much as possible of the uses under real world context and include the
most important parts of the user interface [21]. Furthermore, the tasks should be
structured in a way allowing the participants to compare and evaluate different user
interfaces, which means the usability of TopoNav is compared against another
geolocation app. Google Maps is selected as the geolocation app for comparison - as
TopoNav uses Google Maps API for its source of geographical data, and they both
share common characteristics such as turn-by-turn navigation
Following are the tasks developed for this evaluation:
Task 1 - Selection of Destination
Scenario 1
You are visiting an unfamiliar city for the first time. You arrived at its central railway
station, and just walked out from one of its exits. You were given the mobile interface
earlier today and tried to familiar yourself with it within 15 minutes. You have limited
amount of time available to navigate around this city and you want to start doing that
as soon as possible. You planned ahead for this trip at home and have built a bucket
list of places you want to see. You use the mobile interface to select the destination
you want to go and find the way to the destination.
Based on this scenario, the first task was divided into several sub-tasks to
evaluate the participants’ level of familiarity with the mobile interface and how the
prototype can support the users to select a destination.
The sub-tasks for both TopoNav and Google Maps are:
(a) Did you have enough time to familiar yourself with the mobile interface?
(b) Please search for the appointed destination using its name.
Task 2 - Route Preview
Scenario 2
Before you leave the start point, you want to get an overview of the calculated route.
You try to preview the step-by-step instructions with street photos on the mobile
interface. You also try to estimate how much time it takes for you to get there and how
far away it is from your current location. To make the navigation easier and prevent
yourself from getting lost, you want to ensure this estimation is accurate and you
know the look of all the major landmarks along the path.
The sub-tasks for TopoNav are:
(a) Please estimate the distance from your current location to the destination.
(b) Please estimate the time needed for you to reach the destination.
(c) Observe the information presented on the mobile interface. Can you recognize the
environment on the map?
(d) Please start preview the calculated route. Swipe to left and preview the instruction
and street photo of next step. Swipe to right and preview the instruction and street
photo of previous step. After you finished, did you obtain a clear overview of the
calculated route?
(e) Please start walking toward the destination for 30 meters and stop. Check your
position on the map; were you moving in the correct direction?
(f) Please navigate to the selected destination.
The sub-tasks for Google Maps are:
(a) Please estimate the distance from your current location to the destination.
(b) Please estimate the time needed for you to reach the destination.
(c) Observe the information presented on the mobile interface. Can you recognize the
environment on the map?
(d) Please tap the “Preview” button on the bottom bar to start preview the calculated
route. On the header, swipe to the left and preview next step on the map, swipe to the
right and preview previous step on the map. After you finished, did you obtain a clear
overview of the calculated route?
(e) Please start walking toward the destination for 30 meters and stop. Check your
position on the map; were you moving in the correct direction?
(f) Please navigate to the selected destination.
Task 3 - Identification of Turning Points and Travel Decisions
Scenario 3
On your way walking toward the selected destination, you want to ensure that you are
following the correct route. You try to identify the turning points by observing the
landmarks along the path and, if necessary, comparing them with the street photos
presented on the mobile interface. You want to check whether the landmarks exist and
visible in reality and is correctly presented in the mobile interface. As always, you try
to estimate the distance of the destination from your current location and how much
time left for you to reach the destination. You want to ensure you are moving toward
the destination in the correct direction by watching your movement on the map.
The sub-tasks for both TopoNav and Google Maps are:
(a) Please observe your surroundings and try to identify the next turning point by
landmarks.
(b) Please estimate the distance from your current location to the destination.
(c) Please estimate the time needed for you to reach the destination.
(d) Please navigate to the selected destination.
Task 4 - Destination Identification
Scenario 4
You have been navigating to the destination with the geolocation app. When you think
you have arrived at the destination, please stop and observe the surroundings.
you have arrived at the destination, please stop and observe the surroundings.