Chart layers — GPS, channel markers, weather radar, buoys, track line

Toggle the five chart overlays — GPS position, channel markers (AtoN buoys and beacons from NOAA), NEXRAD weather radar, NOAA weather buoys and the track line — and start a cruising track from the Track line row.

Open the Layers sheet with the round layers button at the top right of the map. Five toggles:

• GPS live position — shows your boat on the chart. Auto-on during an active leg (cannot be turned off while underway), and your boat also shows while a cruising track is recording, whatever this switch says.
• Channel markers — red, green, and yellow buoys and beacons from NOAA. These are aids to navigation, written AtoN on a chart and in most marine software; theONE calls them channel markers on screen and draws them to IALA-B, so a red cone is a starboard-hand mark returning from sea. When NOAA answers for some of them and not others, the chart shows the ones that came back and this row says "Some channel markers could not be loaded from NOAA just now" for ten minutes.
• Weather radar — NEXRAD precipitation, refreshes every 5 minutes. It needs a connection: with no signal the layer is blank or out of date, and its row in Layers says so.
• Buoys — NOAA weather buoys (NDBC), off until you turn it on. Tap a pin for the station — name, number, owner and position — and its latest measured readings, each with its age ("12 min ago"), marked "Measured by NOAA NDBC". A station with nothing in the last 24 hours says so. The station list is kept on this device and refreshed at most once a day, so the pins draw with no signal; readings are fetched at most once an hour and the last ones stay on the device with their age. The pins hide while you edit a route, so a tap there always places a point.
• Track line — shows or hides the line of the track being recorded right now (a cruising track, or the leg's own). The switch never starts or stops recording. The line under it says what the recorder is doing — "Recording · 2.4 nm", "Recording with the leg", or "Not recording — starts by itself when you're moving, while theONE is open" — and when nothing is recording the row has a Start button that begins a cruising track on the spot.

The base chart underneath is the NOAA raster nautical chart. Outside NOAA's coverage (Canadian, Mexican and Bahamian waters, and anywhere else outside U.S. waters) the chart falls back to a plain base map and you'll see an "Outside NOAA coverage — limited to base map" chip. On the Chart tab and the map cards the chip goes by where the boat is — her live GPS position, or the one Locate me last found. With neither, it shows only when no part of the map in view is charted, so zooming out to the whole continent over a boat in U.S. waters does not raise it.

Toggles persist across launches and apply to every map with the layers button — the Chart tab, Mission Control's map card and the map card on TODAY. The route editor has no Layers sheet: its own channel-marker button shares the Channel markers switch, and it draws no radar. There is no separate Follow screen any more; a leg underway is followed on the chart itself. The Track line row reads the real recorder on every one of them, the TODAY card included: if a track is recording, that row says so wherever you open Layers, and its Start button works there too.

Steps

1. Open any chart surface

   The Chart tab, the map card on Mission Control, or the map card on TODAY — each has the layers button, the layers apply to all three, and the Track line row tells the truth about the recorder on each.

2. Open the Layers sheet

   Tap the round layers button at the top right of the map (VoiceOver calls it Map layers). The ? beside Done opens this article.

3. Toggle what you need

   GPS live position shows your boat (auto-on during an active leg). Channel markers draws NOAA buoys and beacons. Weather radar draws NEXRAD precipitation. Buoys draws NOAA weather buoys; tap one for its latest measured readings. Track line shows or hides the recorded line.

4. Start a track from the Track line row

   When the row reads "Not recording", tap Start. A cruising track begins and the row changes to "Recording", then "Recording · 0.3 nm" and counting as you move. A track you start by hand is never stopped for you — end it from the GPS Tracking chip on Mission Control when you tie up. While a leg is recording its own track the row says "Recording with the leg" and there is nothing to start.

5. Done

   Tap Done. The toggles stick across launches and apply on all three.

Related

• Chart — what the chart and map show youRead the chart view — your vessel's position, course over ground, breadcrumb track, and the chart layers underneath.
• Weather radar on the chart — NEXRAD overlayTurn on the NEXRAD weather radar overlay on the chart so you can see precipitation moving across your route.
• Track line — the path you are recording on the chartWhat the line behind your boat is, the difference between recording it and showing it, and how it can start without you touching anything.
• Tracks that start by themselves — the cruising trackWhen you leave the dock without a leg, the app records a cruising track on its own: three minutes above two knots starts it, thirty minutes stopped saves it. Record tracks by itself is on unless you turn it off.
• Go now — cast off from the chart in one tapLeaving right now with nothing planned? One tap on the chart starts a trip, a leg and its track; you name the destination when you tie up.

← All help articles