How To: Set Up a Geofence
Geofencing allows you to set up location based survey triggers, i.e. when a user enters or exits a specified location they will receive a notification from mEMA to complete the assessment.
Note: This feature only works with Android devices, and only when "Record Location at Time of Assessment" has been selected in the participant's User Settings.
Designate a fence when creating a survey assignment:
- Setup an assignment with the Momentary schedule type
- Click Edit Geofences and enter coordinates for the survey-triggering location
- Use the screen that appears to enter the GPS coordinates for up to 10 different locations. Set the radius distance (this is a circular radius around the point). Select if you want the alert to be sent when the user enters, exits or enters and exits the radius.
- The GPS coordinates should be in Decimal Degrees format, for example: XX.XXXXXX, or -XX.XXXXXXX
- You can limit the number of times the user is alerted at this location each day or hour in the Max Times column. If you leave this value at 0 then no limit is placed and the mEMA app will alert the user each time they enter/exit the radius. Additionally, you can limit the time between alerts.
- Note: When setting the radius of the geofence, be aware that phones can have a margin of error of ~20 meters when recording GPS data. This margin of error is reported in the "Accuracy" column of the GPS Data file. Depending on the participant's location you may want to get baseline GPS data to determine the accuracy before setting a smaller radius.
- After inputting the geofence parameters, click SAVE LOCATIONS.
- Note: After saving the locations you also need to click the button "Make Assignment" to save the Geofences