In iOS 6 and later, Maps displays a list of routing apps—including apps installed on the device and in the App Store—when people want transit information for a route.
A routing app provides information about transit options for the currently selected route. People expect routing apps to be quick, easy to use, and—above all—accurate. Following the guidelines in this section helps you give users transit information they can trust and a user experience they appreciate.
Deliver the functionality your app promises. When people see your app in the transit list, they assume that it can help them reach their destination. But if your app can’t provide information about the selected route—or it doesn’t include the type of transit it appears to include—people are unlikely to give it a second chance. It’s essential to represent your app’s capabilities accurately; otherwise, your app can look like it’s intentionally misleading users.
There are two main ways you can give users confidence in your routing app:
Define the geographic regions you support as precisely as possible. For example, if your app helps people get information about bus routes in Paris, your supported region should be Paris, not Île-de-France, and not France.
Be specific about the types of transit that you support. For example, if you specialize in subway information, don’t imply that you provide information about all rail-based transit types.
Streamline the UI for ease of use. Ease of use is especially important for routing apps because people tend to use them under challenging conditions—such as in bright sunlight or in the dim interior of a train, on a bumpy ride, and when they’re in a hurry. Make sure that your text is easy to read in any light and that buttons are easy to tap accurately even when the ride is not smooth.
Focus on the route. Although auxiliary information can be useful, your app should focus on giving users step-by-step directions they can follow to their destination. In particular, you want users to know which step they’re in and how to get to the next step. You can provide additional data—such as timetables and system maps—but don’t make this data more prominent than the transit information.
Provide information for every step of a route. People should never feel abandoned by your app. But even when you accurately report your supported region, you can’t assume that users are already at the first transit stop in a route, or that the last transit stop is at the same location as their destination. To handle this situation, first examine the distances at the beginning and end of the route. If the distances are short enough, provide walking directions from the user’s current location to the first transit stop and from the last transit stop to the user’s final destination. If walking is not a reasonable choice, try to describe the user’s other options. If necessary, you can give users a way to open Maps to get walking or driving directions for these portions of the route.
When users transition to your app from Maps, don’t ask them to reenter information. If users are coming from Maps, you already know the start and end points of the route they’re interested in, so you can present the appropriate transit information as soon as your app opens. If users start your app from the Home screen, provide an easy way for them to enter route details.
Display transit information both graphically and textually. A map view helps people see their complete route in a larger, physical context; a list of steps helps people focus on the actions they must take to arrive at their destination. It’s best when you support both of these tasks and make it easy for users to switch between them.
When your app is chosen from the transit list, it works well to start by displaying the complete route—including walking paths to and from the transit stops, if appropriate—in a map view. A map view gives users an overview of the various steps in their journey and shows them how their route fits into the surrounding geographical area.
Enrich map views with additional information. People expect the maps in your app to behave similarly to other maps they’ve used. In addition to letting users zoom and pan, you should display annotations that give users the information they need. For example, you could display pins that represent the user’s current location, the destination, and transfers or points of interest along the way. Be sure to avoid displaying only a single pin, because it’s hard for users to tell what it represents if there’s no additional context. For more information about using map views in your app, see Map View.
As much as possible, integrate static maps—such as a subway system map—with a map view. A good way to do this is to overlay the static image on the map view so that users can see how their route and their current location relate to the larger transit system.
Give users different ways to sort multiple transit options. Lots of factors influence people’s transit decisions—such as time of day, weather, and how much they’re carrying—so it’s important to make it easy to compare transit options. For example, you could let users sort transit options by start or end time, amount of walking required, number of stops along the way, or number of transfers or different transit types required. Regardless of the order in which you display multiple transit options, make sure that users can instantly distinguish the differences between the options.
Consider using push notifications to give people important information about their route. As much as possible, let people know when transit information changes, so that they can adjust their plans. For example, if a train is delayed or a bus line is temporarily unavailable people might need to choose a different route to their destination. And in a route that includes long stops between steps, people might appreciate being notified when their transport is about to depart for the next part of the journey.