The large number of temples dedicated in recent decades has rendered it impossible to draw a linear timeline of all temples on a standard printed page. We propose an interactive timeline that can run on mobile devices. Rather than display the entire timeline at once, our visualization renders a subset of the temples on an interactive spiral and provides controls for the user to navigate forward and backward through time. Below we will present a mobile app prototype of this visualization, called Temples Timeline, and discuss its implementation and reception.

Introduction and Motivation

Since 1836, The Church of Jesus Christ of Latter-day Saints has dedicated more than 160 temples. Let us consider the challenge of effectively visualizing the dates of these dedications on a timeline. The most obvious approach would be to print the timeline on a standard sheet of paper (fig. 1); however, there are simply too many data points.

Clearly, we need more room. If we space the names of the temples 1 inch (2.5 cm) apart, the chart grows to approximately 13 feet long (4 meters), which is too large to conveniently print and display. What if, instead, we saved the chart in an electronic format such as a PDF or an image? This would, naturally, be less expensive than printing it and would permit wider distribution. However, even on a large computer screen, the user would have to scroll around a great deal to find a specific temple. Zooming out would reduce the chart to illegibility. The problem would be exacerbated if the user were viewing the timeline on a small device, such as a tablet or smartphone.

In a previous BYU Studies Quarterly article, a computer program for displaying the chronology of apostolic succession in the Church, called Latter-day Apostles, on mobile devices was described. The authors describe the First Presidency and the Twelve mathematically as “well-ordered sets,” in other words, a set in which there is a “first” element (the Apostle with the longest tenure), a “second” element (the Apostle with the second-longest tenure), and so on all the way down to the “last” element—the most recently ordained Apostle.¹

We can describe the set of all current temples the same way. There is a “first” element (Kirtland, Ohio), a “second” element (Nauvoo, Illinois), and so on until the most recently announced temple. The difference is that the set of operating temples is generally always increasing in size, whereas the set of living Apostles is limited to approximately fifteen individuals at a time. Nevertheless, we can adapt some principles from the previously mentioned article to address the problem of visualizing a timeline of temples on a small screen.

Design

The Latter-day Apostles app uses a dual-ring layout, displaying the First Presidency on the inner ring and the Quorum of the Twelve Apostles on the outer ring. This works well for the relatively fixed number of Apostles at any given time.² To visualize a timeline of all the temples, we chose a spiral-based visualization.³ The use of spirals for interactive data visualization was introduced in 1998 by John Carlis and Joseph Konstan. All circles are positioned along a spiral line, with the diameters increasing gradually from the center to the outer end of the spiral.⁴ As the user adjusts the date, the positions of the current on-screen temples are updated accordingly. The most recently dedicated temples will be on the outer rim of the spiral, with older temples in the middle, arranged counterclockwise by age. By reducing the size of the interior temples, we increase the total number of temples on the screen. Our assumption is that users will be more likely to interact with icons along the outer periphery of the spiral, so reducing the size of the inner icons is an acceptable compromise (see figs. 2a and 2b).

Prototype

As a proof of concept of our spiral visualization scheme, we have implemented a mobile app called Temples Timeline.⁵ It is currently available for free on the Apple App Store, Google Play, and Amazon Appstore. The app is available in both English (fig. 2a) and Mandarin Chinese (fig. 2b).

To keep the app running at interactive speeds, we limit the number of temples displayed to about sixty. In other words, the small icons near the center of the spiral do not continue ad infinitum. Once they are too small to see (approximately 1⁄16-inch diameter), the app no longer renders the image.

Interaction

The screen display is divided into two areas. The largest is the spiral visualization itself. Just below the visualization is a slider, with a knob (called a “thumb”) that the user can drag left or right. In order to increase the app’s usefulness, we included several options for interacting with the spiral:

The user can move forward or backward in time by moving the slider thumb, by tapping the left/right arrow buttons, or simply by rotating the spiral itself (see figs. 3, 4, and 5).
The user can look up specific temples by name (fig. 6) or by year (figs. 7a and 7b).
Tapping any temple image in the spiral opens a larger photo of that temple and shows additional information, such as announcement and dedication dates (figs. 8 and 9).

Future Work

Just as the Latter-day Apostles app’s method for visualizing apostolic succession ⁶ was successfully applied to other domains,⁷ we believe the visualization metaphor described in this paper can be readily applied to other forms of data. Possible applications of this visualization could include:

A history of an organization, such as a business, university, or country.
A succession of heads of state (for example, kings and presidents) of a country.
A list of scientific discoveries in a given domain.
An alternative representation of the periodic table of elements.

As a proof of concept of applying this visualization to alternate data sets, we are developing two additional apps using a similar spiral layout. One focuses on visualizing Chinese surnames and culture,⁸ while the other displays the historical milestones of Brigham Young University–Hawaii (figs. 10a and 10b).

Discussion and Conclusion

In this paper, we have presented a technique for visualizing well-ordered sets on a handheld device. In contrast to the prior work of Jin, Delai, and Draper, which was limited to approximately fifteen on-screen icons at a time, our technique can accommodate many times this number.

At the time of this writing, the Temples Timeline app has been downloaded over five hundred times. Initial feedback from users has been overwhelmingly positive, and some features (in particular, the search-by-name feature shown in figure 6) were a direct result of users’ suggestions. It is our hope that the Temples Timeline app will give its users a renewed appreciation for the beauty and sanctity of the temples as well as inspire Latter-day Saint software developers to build more apps that celebrate the unique culture and doctrines of the restored Church of Jesus Christ.

Litian Zhang

BYU Studies Publications