Geofence Alerts for Families

Geofencing is one of those features that sounds technical but is genuinely useful in everyday life. Set a virtual circle around a place — home, school, a kid’s sports field — and your phone notifies you when a family member crosses it. No maps to check, no “text me when you get there” reminders.

This guide explains what geofences are, the most useful places to set them up, the battery and privacy trade-offs you should know, and how to configure them in CircleMap.

What is a geofence?

A geofence is a virtual boundary around a real-world location. The classic example: a 100-meter circle around your house. When a phone enters or leaves that circle, the app can fire an event — usually a notification.

The technology has been around since smartphone GPS got accurate enough (roughly 2010). Modern phones support it natively: iOS exposes it via CLCircularRegion, Android via the GeofencingApi. Both operating systems handle the heavy lifting — your app just registers the regions and waits for the OS to call back when something crosses them.

The most useful places to set geofences

You probably don’t need many. Three to five well-chosen places usually beats fifteen marginal ones, both for clarity and for battery.

Home

The single most useful geofence. “Sam left home” in the morning is a useful signal. “Sam arrived home” in the afternoon is the one parents wait for. Setting a 150–200 meter radius works well in most suburban contexts; tighter in dense urban areas to avoid false positives from neighbors’ buildings.

School (or daycare)

Especially valuable for the school dismissal window when parents are wondering if pickup is needed. A 200-meter geofence around the school covers the playground and main entrances.

Work

Useful for partners coordinating commute timing, or for parents tracking when a teen arrives at a part-time job.

Sports fields, music lessons, after-school programs

If your week revolves around drop-offs and pick-ups at recurring places, geofences are dramatically faster than checking a map.

The ones not to set

Avoid geofences for places people don’t go often, or places where the entry/exit pattern is fuzzy (the gym, where someone might come and go several times). The notification fatigue isn’t worth it.

How geofence alerts work technically

A few things worth knowing because they explain why alerts sometimes don’t fire instantly:

• OS-throttled. Both iOS and Android batch geofence checks to save battery. An entry/exit event can be delivered up to a minute or two after the actual crossing.
• Indoor uncertainty. GPS accuracy degrades indoors (especially in concrete buildings). The OS uses Wi-Fi and cell tower triangulation to fill in gaps, but expect occasional false positives if the geofence is small and the location is indoor.
• Geofence count limits. iOS allows up to 20 active geofences per app; Android is more generous but still bounded. Apps that need more rotate them in and out as the user moves — you don’t need to think about this, but it’s why setting 50 places might result in “some don’t fire.”
• Permission required. “Always” location permission on iOS, background location on Android. If you only granted “While Using,” geofences won’t fire while the app is closed.

Setting up geofences in CircleMap

1. Open the circle you want geofences in (e.g., your Family circle).
2. Tap the “Places” tab at the top of the circle.
3. Tap “+ Add Place” and either search for an address, drop a pin on the map, or use your current location.
4. Name the place (“Home,” “School,” etc.) and adjust the radius. The default is 150 meters, which works for most cases.
5. Choose who gets alerts. Notify everyone in the circle, just yourself, or specific members. For a kid’s school, parents only is usually right.
6. Choose alert direction. Arrival only, departure only, or both. Both is the default.

Battery and privacy trade-offs

Battery

Geofencing itself is essentially free in battery terms because the OS handles it. The phone is already tracking location for other reasons; checking whether the user crossed a saved circle adds almost nothing. The bigger battery hit is having “Always” location permission enabled on the app at all — that’s the cost, and it’s mostly fixed regardless of how many geofences you have.

Privacy

Geofence events are tied to specific places, which makes them more sensitive than raw location pings. A few practical considerations:

• Who sees the events. In CircleMap, geofence events are visible only to circle members. They’re not stored beyond the activity log retention window (90 days).
• Don’t set geofences on places that imply something private. “Therapist’s office” or “recovery meeting” geofences create a record of attendance you may not want shared.
• Tell other circle members. If you’re adding a geofence on a teen’s phone, tell them. Surprise geofences damage trust.

Common geofence problems and fixes

“The notification fires hours late”

Almost always a permission or background-mode issue. On iPhone, confirm “Always” location permission is on. On Android, exclude the app from battery optimization (Settings › Apps › CircleMap › Battery › Unrestricted).

“I get a notification when I’m clearly nowhere near the place”

GPS drift, especially in tall-building environments. Try increasing the geofence radius slightly (150m → 200m). False positives often cluster in specific areas; if it’s consistent, the place is in a hard-for-GPS spot.

“Some geofences fire, some don’t”

If you have many geofences, the OS may have evicted the ones that aren’t fired often. CircleMap rotates active regions based on recency — if you have 25 places but only visit 5 regularly, the active 20 will skew toward the regular ones.