Geofence Analyzers in EarthRanger automatically generate Events when a subject from a specified group crosses a defined linear boundary on the map. 

If an alert rule is configured, the Event can also trigger an alert notification.
 

1. Define the Subject Group

Ensure that a Subject Group containing all the subjects you want to monitor is configured. If no such group exists, create one. For more details on configuring Subject Groups, refer to the About Subject Groups article. 

If you need a Subject Group for specific subjects but don’t want it to appear under the map layers in the UI, you can:

1. Create the group.
2. Add the desired subjects.
3. Uncheck the Visible checkbox.

This will hide the Subject Group from the map layers while keeping it functional for the analyzer.

2. Define the Linear Boundaries
 

Each Geofence Analyzer can include two levels of reporting: Warning and Critical. Configuring both is optional.

• Warning Boundary: Triggers an Event with Amber priority when crossed.
• Critical Boundary: Triggers an Event with Red priority when crossed. 
  
   

Example Configuration

In this example, the analyzed subjects are a group of elephants. The Geofence Analyzer is set up to notify users when an elephant approaches or enters a village.

• The Critical boundary is the village limit.
• The Warning boundary is a buffer set 2 km outside the critical boundary.
   

When a subject crosses the warning boundary, EarthRanger generates an Amber priority Event, alerting users that the subject is nearing the area. If the subject crosses the critical boundary, EarthRanger generates a Red priority Event, indicating the subject has entered the village.

The Warning geometry defines the region where a subject is approaching the area, while the Critical geometry defines the region where a subject has already entered the area.
 

Adding Linear Boundary Features
 

You must create or upload the linear boundaries to use for the geofence. EarthRanger supports two options: 

• Upload a file with the boundary features.
• Draw the features directly in EarthRanger.

For instructions on creating or uploading map features, refer to Draw Features directly in EarthRanger.
 

3. Create the Feature Groups

You need a separate Feature Group for each reporting level of the analyzer (Warning, Critical, or Containment).

Refer to the Feature Groups article for more details on creating and managing Feature Groups.
 

 4. Create the Analyzer

Once the Subject and Feature Groups are set up, you can create the Geofence Analyzer.

1. Navigate to Home > Analyzers > Geofence Analyzers, then click Add Geofence Analyzer.
2. Configure the Analyzer:
   1. Name the Analyzer: Choose a clear, easily identifiable name.
   2. Select the Subject Group: Choose the Subject Group you defined in Step 1. Each Analyzer can monitor only one Subject Group.
      1. If you need to monitor multiple Subject Groups, you can:
         1. Create a separate Analyzer for each group.
         2. Create an umbrella Subject Group that combines all subjects from the groups.
      2. If you skipped Step 1, you can create a Subject Group directly in the Analyzer settings by clicking the green “+” icon.
   3. Set Spatial Features: Assign Feature Groups to each reporting level:
      1. Use the dropdown lists to select the appropriate Feature Group (from Step 3) for each level.
      2. Feature Groups must have valid geometries:
         1. Critical and Warning geofences require Line geometries.
         2. Containment regions require Polygon geometries.
      3. Each reporting level supports only one Feature Group.
      4. If you skipped Step 3, you can create a Feature Group directly in the Analyzer settings by clicking the green “+” icon.

Advanced Settings (Optional)

Analyzer ID
The system automatically assigns an identification code (ID) to the Analyzer. This value is not editable.

Analysis Time Frame
The Analysis Time Frame determines how far back in time the Analyzer reviews track data to generate Geofence Events.

• When EarthRanger receives new observations (tracking points), the Analyzer reviews only the data within the configured time range.
• This is critical for devices that store data for a period before synchronizing with EarthRanger. For example:
  • If a collar stores data for 7 days but the Analysis Time Frame is set to 48 hours, EarthRanger analyzes only the most recent 48 hours of data when it is uploaded.
  • To ensure the system detects geofence crossings during the full 7-day period, set the Analysis Time Frame to at least 7 days.
     

• The system interpolates between the last observation outside the area and the first observation inside it.
• Both points must fall within the Analysis Time Frame. If the last observation before the crossing is outside the configured time frame, no Event will be generated, even if the crossing occurs within the time frame.