Regions (Waypoints)

The base topic for publishes from the devices (OwnTracks apps) is what you configure it to be in the app's preferences/settings. For argument's sake we'll use the default owntracks/<user>/<device> as our example.

This base topic is used for publishes of type location (see JSON). All messages published to this base topic are retained if you have configured the app to retain them.

Additionally, if you've configured a waypoint, regions, or geo-fence (we intermix these terms a lot to mean basically the same thing), a transition event will be published upon entering or leaving a waypoint:

  • radius (if its value is greater than 0)
  • description with the name you set for the waypoint
  • event with a value of "enter" or "leave", depending on whether the device is entering or leaving a configured region, respectively.
  • rid (> January 2021) with the region ID of the region.

If you set up a region (or waypoint or geo-fence, you get the drift), the app publishes that region (with retain=0 irrespective of your general preference) to the base topic with /waypoints tacked onto the topic (e.g. owntracks/<user>/<device>/waypoints) with the payload for _type=waypoint as specified in the JSON page. Entering or leaving a waypoint will be published as a transition message and will contain a wtst (for historical purposes) with the timestamp of when the region was originally defined.

For example, If Jane configures a region on her iPhone, the app could publish the following payload

{
    "_type": "waypoint",
    "desc": "Paris is lovely",
    "lat": "48.858330",
    "lon": "2.295130",
    "rad": "50",
    "tst": "1385997757",
    "rid": "f7676c"
}

When you set up a region (with a description and a radius), this region is published to the broker with the current time stamp. If you update the region definition on the device at a later stage, the region is re-published, with the original timestamp, but with possibly new description and/or radius and latitude / longitude, but with the same rid. To be precise, the rid (region ID) is used as an identifier of the region even if it is later modified on the device.

Subscribers to the broker (our apps and any other program) can avoid getting regions by subscribing to, say, owntracks/+/+; also broker ACLs can prohibit access to owntracks/+/+/waypoints for particular users if so desired. Conversely, all messages published by the apps (location, transition, and waypoint) are available with a subscription to owntracks/#.

The OwnTracks apps may keep track of regions, e.g. for displaying to users.

In regions

When the apps publish a _type = location message, they add to that an array called inregions (and as from January 2021 an array called inrids) with the names of the regions and their rids respectively. The inregions array might be consumed by humans whereas the inrids array would be consumed by developers who will wish to associate the region IDs (rid) with the values in inrids.

Adding on iOS

On iOS you can navigate to the place where you want to place a region, Tap long and edit the Region. The region is always placed at the center of the map (hence it's predefined name Center, which you should change to something meaningful). With a bit of practice, you can then drag the region to it's final destination on the map or, and this may be easier, edit the region and specify its exact coordinates.

Adding on Android

On Android, regions can be configured on a separate activity. Coordinates for the geographical region can be entered by hand or by using the place picker.

Remote loading of regions

Instead of configuring multiple regions on the device, they can be loaded remotely with the setWaypoints cmd message if remote configuration is enabled on the device.

You can use this to import individual regions or groups of pre-configured regions which are merged into the existing regions definition on the device. Recall, however, that the rid element is like a key which uniquely identifies each region / waypoint.

Deleting regions

On iOS a region can be deleted by swiping it away. On Android, a long press is required.

Beacons Ranging

In addition to circular regions, the iOS app can monitor its proximity to BLE Beacons.