It matters! Having a voice and choosing the right words matter. Whether it is the Voice that gets the popular vote on the acclaimed TV show or the words that capture the attention of voters on a heated political debate — it matters! It is no different in the mapping industry. Today, open mobile navigation has a voice, and choosing the right words for the turn-by-turn service matters.
The Mapzen Turn-by-Turn service is mobile focused, and it is essential to have verbal instructions that will work well with various text-to-speech(TTS) engines. Depending on the maneuver, we return textual instructions as well as up to three verbal instructions. These include the following:
- The verbal transition alert instruction is intended to provide advance notice of an impending maneuver – kind of a wake up call to get the user prepared to make a maneuver.
- The verbal pre transition instruction is more detailed and is presented just before the maneuver is made.
- The verbal post transition instruction describes what to do after making the maneuver - usually something like continue for some distance, but can also identify if the road name changes.
Maneuver Instructions Example:
|Turn right onto East Chocolate Avenue/US 422. Continue on US 422.
|Turn right onto East Chocolate Avenue.
|Turn right onto East Chocolate Avenue, U.S. 4 22.
|Continue on U.S. 4 22 for 3.3 miles.
Another objective of this service is to provide TTS enhancements that mimic how people actually answer when giving verbal directions. We format or expand route names so they are spoken correctly. The TTS enhancements can be implemented based on location. Since the United States’ road network is large and diverse, we chose this region and selected several examples from different states.
For US routes, we transform
U.S. so it is pronounced as
U S and not as the pronoun
us or the expanded
|US 1 North
|U.S. 1 North
|US 22 East
|U.S. 22 East
For state routes, we expand abbreviations - for the first example below,
MA 3 South will be expanded to
Massachusetts 3 South so it will not be pronounced as
Maw three South.
|MA 3 South
|Massachusetts 3 South
|MD 32 West
|Maryland 32 West
For route numbers and house numbers, we group and format the numbers so they will be pronounced properly. For numbers greater than two digits, the numbers are transformed into groups of two, from right to left. In the example below, the interstate number
695 is transformed to
6 95, so it will be pronounced
six ninety-five instead of
six hundred ninety-five.
Similarly, the four digit state route
1021 is transformed to
10 21, so it will be pronounced
ten twenty-one instead of
one thousand twenty-one. When the numbers are grouped by two, any leading zero will become the letter
o. Therefore, the US route
101 is transformed to
1 o1, so it will be pronounced
one oh one instead of
one hundred one. For any number that ends with a double zero, the double zero is transformed to
hundred. The house number 7700 below is transformed to
77 hundred, so it will not be pronounced as
seven thousand seven hundred. In the final example below, notice how the house number
905 is transformed to
9 o5, however the street name
203rd does not need changed because it is already properly formatted for verbal directions.
|I 695 West
|Interstate 6 95 West
|State Route 10 21
|US 101 North
|U.S. 1 o1 North
|7700 Mapzen Way
|77 hundred Mapzen Way
|905 203rd Street
|9 o5 203rd Street
The examples below represent location specific interpretations. The first two examples demonstrate the difference between interpreting the route name as either a state abbreviation or as a county road. The third example represents a route specific to the state of Texas.
|Colorado, United States
|County Road 7
|Ohio, United States
|Farm to Market Road 10 18
|Texas, United States
The Mapzen Turn-by-Turn service will detect short maneuvers and combine separate verbal instructions into one multi-cue instruction so the user will be prepared for each transition. The following example illustrates how in the 2nd maneuver we append the verbal pre transition instruction with the next verbal transition alert instruction.
Enhancements like these matter because it matters what you say and how you say it. Every turn-by-turn service has something to say – we just strive to say it better! You can hear the voice guidance in Eraser Map, our privacy-focused Android application.