TrackPoint Monitor

The Lumia TrackPoint Monitor API is deprecated. New apps should not use the API as it will not be supported in future devices.

The TrackPoint Monitor API provides information about the user's movements. It is very similar to the Place Monitor API, but instead of places, such as home or work, it tracks visited points.

When motion data is set to Basic, TrackPoint Monitor works passively using mainly cell towers and Wi-Fi hotspots to figure out the device's location. GPS information is used only if another application is using GPS. However, apps need to be aware that track points provided by the app may not be fully accurate. Think of it more as a city tracker
(it can provide positions in the level of city blocks) rather than a fitness tracker (which can provide position in the level of few meters). In typical cases where Track Point Monitor works passively (uses cell tower and Wi-Fi base station data), track points will be recorded every 5 minutes and the minimum distance between two track points is about 500
meters. Track point accuracy depends on the frequency and quality of position data, which is dependent on the existence of cell towers and Wi-Fi hotspots. For example, jogging in a park without an active GPS session might record just one point, since the phone stays connected all the time to a single cellular tower.

When motion data is set to Detailed, TrackPoint Monitor works actively using mainly GPS to figure out the device's location. Compared to the Basic mode, the TrackPoint Monitor API will be able to provide more data points and increase the accuracy of the data points. As a result, battery consumption will be higher but still significantly less compared to normal GPS usage. In this active mode, TrackPoint Monitor tries to acquire location updates every 30s to 60s when the user is moving. The location acquisition is done very power efficiently, adapting GPS usage based on the motion type and the speed of the user. TrackPoint Monitor goes to sleep-mode when the user is not moving. In sleep-mode, GPS is not used, and power consumption of the Detailed mode equals the Basic mode consumption. Due to the nature of the low power GPS usage, the accuracy and interval of the fixes may vary in GPS signal challenged environments like in deep urban canyons or when the device in held in a place where it cannot acquire good GPS signals.

The highest track points registration interval is at 30 seconds (API implementation will wait 30 seconds from the last track point until it records a new one) and only occurs when a minimum distance of 50 meters has been travelled from the last recorded track point. For example, if the user stays for a long period of time within a given 50 meter area, TrackPoint Monitor will only record a single track point for that area. This behavior is, however, typical only for scenarios in which the device has an active GPS session.

The TrackPoint Monitor API provides the following parameters:

  • LengthOfStay┬áindicates how long the device stayed at this point.
  • Position┬áis the geographic position of the track point.
  • Radius┬áis the estimated radius of a circular area around the location which reflects the uncertainty of the place. Uncertainty depends on various factors, like how the device is being used and environmental factors like the population of cell towers and Wi-Fi hotspots.
  • Timestamp┬áis the time of entry to the location. This is provided with 5 minute accuracy.
  • PlaceId┬áis the ID of the place that overlaps or co-exists over the recorded track point when there is one. The ID is the same as what the Place Monitor API would provide for a given place.

Examples of TrackPoint Monitor data

For example, a morning commute from home to work in a sub-urban area could look like this (total travel distance 13 km or approx. 8 miles):


A bicycling exercise is tracked with the Basic mode on the device (with a distance of 26 km, and an average speed of 22 km/h). The red line is from a separate GPS device for reference to indicate the actual route taken, and the blue dots are the track points:


The following is the same route as above, but with the Detailed mode activated. The blue dots are the track points.