Alarms

MMfA is able to sound an alarm, based on your distance from a mark, or whether you are inside or outside an area defined by a route. Alarms are also used for AIS collision alerts, DSC or AIS distress signals. Use of alarms requires the Memory-Map Professional license. Sign in to activate your Professional license, or use a free 10 day demo period for evaluation.

Mark Proximity / Anchor Alarm

You can set an alarm on a Mark, and get a notification when you approach that point (Proximity Alarm), or when you stray to far from it (Anchor Alarm).

Create a Mark, Tap the drop-down menu (or right-click), and Edit the mark. When you enable the alarm, you can set the Anchor and the Proximity alarm distance separately. To set a Proximity alarm, leave the Anchor alarm distance at zero.

When you set an anchor alarm, typically you don't want the alarm to go off when you are a long distance from that point. So if you enter an Anchor alarm distance and leave the Proximity alarm distance at zero, the app automatically suppresses the alarm when you are double the distance plus 1km from the point. You can change this behavior by entering a different Proximity alarm distance.

The Anchor alarm radius must be smaller than the Proximity alarm radius. The alarm zone is actually the annulus between the two.

Geofence and Exclusion Zone Alarms

You can use a route to define a region, with an alarm to sound depending on whether you are inside or outside the region. A Geofence alarm sounds when you go outside the region, while an Exclusion Zone alarm sounds when you are inside the region.

First create a normal route (see here). The finish point doesn't have to be exactly on the start point, as the region is defined by a polygon with an implicit line from the finish back to the start.

Right click one of the route points, or tap the blue context button, and Edit Route. Set the Alarm checkbox, and select either Geofence or Exclusion Zone.

CrossTrack Alarm

You can also set an alarm to sound if you go too far off-course when you are following a route. This is based on the "CrossTrack" distance, which is your distance to the left or right of the route. This is also set in the Edit Route dialog. However, it is important to note that the crosstrack alarm is a global setting that applies whenever you are following any route. The Geofence/Exclusion Zone alarm is a property of the specific route that you are editing.

Alarm Notifications

When the alarm goes off, the app displays a system notification for iOS and Android. You can dismiss the notification by tapping it. The notification is automatically dismissed when the alarm condition ends (eg, you move out of the area).

The notification is continuously updated, giving the name of the mark causing the alarm, and your distance from it. If you have a smart watch or similar device, it displays the updated notification text on your wrist.

Note that on Android, use of the background GPS track recording requires the use of a silent system notification. It is important to enable notifications on Android if you want to record your track.

On Windows, Mac and Linux, the app doesn't use a system notification, it just plays a sound and shows a message at the top of the MMfA window.

Android Notification Bug

Please note that there is a bug in the Android SDK libraries that prevents a notification from making a sound when the app is in the background or when the phone is off. The notification only makes a sound if the app is running in the foreground. We realize this makes the alarms of limited use for Android. You can google "Android notifications delayed until app opens" and see that many apps are affected by this bug. There are suggested workarounds but nothing that we have found works on newer mainstream devices. The problem is that everyone's phone is beeping and chiming way to much, with notifications from numerous apps, so Google is trying to limit notifications from backgrounded apps. Unfortunately they made it impossible and the result is that many apps are not getting notifications through. Hopefully this situation will be resolved in future updates.

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