Start tracking
This section guides you through building a tracking application that captures device locations.
Create a tracker
Create a tracker resource to store and process position updates from your devices. You can use the Amazon Location Service console, the AWS CLI, or the Amazon Location APIs.
Each position update stored in your tracker resources can include a measure of position accuracy, and up to three fields of metadata about the position or device that you want to store. The metadata is stored as key-value pairs, and can store information such as speed, direction, tire pressure, or engine temperature.
Trackers filter position updates as they are received. This reduces visual noise in your device paths (called jitter), and reduces the number of false geofence entry and exit events. This also helps manage costs by reducing the number of position updates stored, and reducing the number of geofence evaluations initiated.
Trackers offer three position filtering options to help manage costs and reduce jitter in your location updates.
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Accuracy-based – Use with any device that provides an accuracy measurement. Most mobile devices provide this information. The accuracy of each position measurement is affected by many environmental factors, including GPS satellite reception, landscape, and the proximity of Wi-Fi and Bluetooth devices. Most devices, including most mobile devices, can provide an estimate of the accuracy of the measurement along with the measurement. With
AccuracyBasedfiltering, Amazon Location ignores location updates if the device moved less than the measured accuracy. For example, if two consecutive updates from a device have an accuracy range of 5 m and 10 m, Amazon Location ignores the second update if the device has moved less than 15 m. Amazon Location neither evaluates ignored updates against geofences, nor stores them.When accuracy is not provided, it is treated as zero, and the measurement is considered perfectly accurate.
Note
You can also use accuracy-based filtering to remove all filtering. If you select accuracy-based filtering, but override all accuracy data to zero, or omit the accuracy entirely, then Amazon Location will not filter out any updates.
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Distance-based – Use when your devices do not provide an accuracy measurement, but you still want to take advantage of filtering to reduce jitter and manage costs.
DistanceBasedfiltering ignores location updates in which devices have moved less than 30 m (98.4 ft). When you useDistanceBasedposition filtering, Amazon Location neither evaluates these ignored updates against geofences nor stores the updates.The accuracy of most mobile devices, including the average accuracy of iOS and Android devices, is within 15 m. In most applications,
DistanceBasedfiltering can reduce the effect of location inaccuracies when displaying device trajectory on a map, and the bouncing effect of multiple consecutive entry and exit events when devices are near the border of a geofence. It can also help reduce the cost of your application, by making fewer calls to evaluate against linked geofences or retrieve device positions. -
Time-based – (default) Use when your devices send position updates very frequently (more than once every 30 seconds), and you want to achieve near real-time geofence evaluations without storing every update. In
TimeBasedfiltering, every location update is evaluated against linked geofence collections, but not every location update is stored. If your update frequency is more often than 30 seconds, only one update per 30 seconds is stored for each unique device ID.
Note
Be mindful of the costs of your tracking application when deciding your filtering method and the frequency of position updates. You are billed for every location update and once for evaluating the position update against each linked geofence collection. For example, when using time-based filtering, if your tracker is linked to two geofence collections, every position update will count as one location update request and two geofence collection evaluations. If you are reporting position updates every 5 seconds for your devices and using time-based filtering, you will be billed for 720 location updates and 1,440 geofence evaluations per hour for each device.
Your bill is not affected by the number of geofences in each collection. Since each geofence collection may contain up to 50,000 geofences, you may want to combine your geofences into fewer collections, where possible, to reduce your cost of geofence evaluations.
Note
Billing depends on your usage. You may incur fees for the use of other AWS
services. For more information, see Amazon Location Service
pricing
Authenticating your requests
Once you create a tracker resource and you're ready to begin evaluating device positions against geofences, choose how you would authenticate your requests:
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To explore ways you can access the services, see Accessing Amazon Location Service.
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If you have a website with anonymous users, or you want to use your own authentication process, or combine multiple authentication methods, see Allowing unauthenticated guest access to your application using Amazon Cognito.
Example
The following example shows the passing of the unauthenticated identity pool as credentials when using the AWS JavaScript SDK
. const AWS = require("aws-sdk"); // Exchange the unauthenticated identity pool you created for credentials const credentials = new AWS.CognitoIdentityCredentials({ IdentityPoolId: "us-east-1:54f2ba88-9390-498d-aaa5-0d97fb7ca3bd" }); const client = new AWS.Location({ credentials, region: "us-east-1" // The region containing both the identity pool and tracker resource }); // Send device position updates const rsp = await location .batchUpdateDevicePosition({ TrackerName: "ExampleTracker", Updates: [ { DeviceId: "ExampleDevice-1", Position: [-123.4567, 45.6789], SampleTime: "2020-10-02T19:09:07.327Z" }, { DeviceId: "ExampleDevice-2", Position: [-123.123, 45.123], SampleTime: "2020-10-02T19:10:32Z" } ] }) .promise()
Update your tracker with a device position
To track your devices, you can post device position updates to your tracker. You can later retrieve these device positions or the device position history from your tracker resource.
Each position update must include the device ID, a timestamp , and a position. You may optionally include other metadata, including accuracy and up to 3 key-value pairs for your own use.
If your tracker is linked to one or more geofence collections, updates will be
evaluated against those geofences (following the filtering rules that you specified
for the tracker). If a device breaches a geofenced area (by moving from inside the
area to outside, or vice versa), you will receive events in EventBridge. These
ENTER or EXIT events include the position update
details, including the device ID, the timestamp, and any associated metadata.
Note
For more information about position filtering, see Create a tracker.
For more information about geofence events, see Reacting to Amazon Location Service events with Amazon EventBridge.
Use either of these methods to send device updates:
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Send MQTT updates to an AWS IoT Core resource and link it to your tracker resource.
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Send location updates using the Amazon Location Trackers API, by using the AWS CLI, or the Amazon Location APIs. You can use the AWS SDKs to call the APIs from your iOS or Android application.
Get a device's location history from a tracker
Your Amazon Location tracker resource maintains the location history of all your tracked devices for a period of 30 days. You can retrieve device location history, including all associated metadata, from your tracker resource. The following examples use the AWS CLI, or the Amazon Location APIs.
