IEEE Consumer Electronics Magazine - May 2018 - 74

FIGURE 1. A user visualizing and interacting with an augmented Toronto city model and
data on real tables with HoloLens.

analysis [2]. Lv et al. built a 3-D Shenzhen, China, city web
platform based on a geographical information system to visualize different types of city data, such as 3-D building model
data, residents' information, and real-time and historical traffic
data [3]. This indicates the progress of 3-D technologies that
facilitate the process of 3-D city data creation [4].
Most city data visualization applications, such as the two
aforementioned examples, are implemented with traditional
desktops or laptops and demonstrated through daily use computer monitors. Though this method can satisfy the requirements for city data visualization, it is hard to improve flexibility
and the user interaction natural level. However, recent developments in AR technology, especially the Microsoft HoloLens,
have produced new ways to visualize city data.
▼ Flexibility: Compared with traditional monitors, which are
usually fixed at one position with limited rotation angles,
this head-mounted HoloLens AR device can manipulate and
demonstrate large-scale city data (up to 1.4 m × 1 m in our
implementation) with more flexibility, such as on a table, a
wall, and the ground or even in the air, and with either horizontal or vertical views.
▼ Natural interaction: HoloLens offers a more natural interaction experience than using indirect interfaces, such as a
keyboard or a mouse; e.g., if a user wearing HoloLens

FIGURE 2. A Microsoft HoloLens AR device.
74 IEEE Consumer Electronics Magazine

MAy 2018

wants to see more details of a city
region, he/she can simply move
close to check it and also interact
with the city data through gesture or
voice commands naturally.
In this article, we present a method
to visualize various types of Toronto
city data in 3-D form with HoloLens.
Figure 1 is an example showing a user
wearing HoloLens to visualize and
interact with an augmented Toronto 3-D
city model and related city data. With
our work, users can obtain and observe
various types of city data efficiently and
are able to manipulate and interact with
the data easily through HoloLens, which
offers great potential to better explore
and manage city data.

AR TECHNOLOGY
AR technology enables users to see a combination of real
and virtual things in real time through augmenting virtual
holograms on the real environment. It can be used in many
fields, such as gaming, education, machine operation, and
medical treatments [5]. AR differs from virtual-reality
(VR) technology in that VR totally blocks users from the
real surrounding environment to generate an immersive
virtual environment [6]. As a result, AR is mainly used to
develop applications interacting with the real world, whereas VR is mostly deployed to design applications requiring
a high degree of immersion.
AR devices offer various display methods, including
head-mounted, handheld, and head-up, among others.
Google Glass uses a pair of eyeglasses to show augmented
contents on the real environment [7]. Recently, the Pokémon Go game has attracted thousands of players through
superimposing their animated creatures on players' phone
screens, which scan the real surrounding environments [8].
HoloLens, shown in Figure 2, is developed by Microsoft
and demonstrates the cutting-edge technologies in AR
devices. Different from most previous AR devices, which
need to be connected with an external computing machine
through a cable or wireless connection, HoloLens itself
integrates all required components to become a complete
AR system running the Windows 10 operating system (OS).
It is built with one depth camera, two pairs of environmental understanding cameras, one video camera, two speakers,
one inertial measurement unit, a holographic projection
system, and many other parts. The processing units of the
HoloLens consist of a central processing unit (CPU) and a
holographic processing unit (HPU). Therefore, HoloLens
can process all required tasks, such as detecting the surrounding environment and interacting with users through
gesture and voice commands. Considering its advanced
capabilities, we chose HoloLens as the AR device in
our implementation.

Table of Contents for the Digital Edition of IEEE Consumer Electronics Magazine - May 2018