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Depth & Bathymetry

Bristol Maps can save the depth readings coming off your sounder and build them into your own depth picture -- points, a heatmap, and contour lines. Over a season on the same ground that adds up to something no chart gives you.

Everything here lives in Settings > Depth & Bathymetry ("Depth recording, layers, cloud sync (beta)").

Beta feature

The settings page describes itself as a beta feature. Your own recorded depth is a record of where your boat has been, not a survey. Do not navigate on it in place of a chart and a sounder.

Before you start

You need depth arriving from a sounder on the NMEA network. See Depth Sounder Setup -- and get the Depth Sounder Offset right before you record anything, because every reading you save carries that offset with it.

Recording

Setting Description
Record Depth Data Save depth readings from your sounder as you drive around.
Recording Interval (s) Seconds between saved depth readings.
Transducer Model Your sounder brand -- used to interpret hardness data correctly. Choices: Generic, Furuno, Simrad, Garmin.

Interval is a trade-off

A short interval gives denser coverage and a bigger database. A long interval keeps things light but leaves gaps when you're running fast. Start in the middle and adjust after a trip.

Display modes

Four layers, each with its own switch. You can run more than one at a time.

Setting Description
Show Depth Points Show individual recorded depth readings on the map.
Show Depth Heatmap Shade the map by depth using your recorded readings.
Show Contour Lines Draw depth contour lines generated from your recorded readings.
Show Bottom Hardness Show bottom hardness readings where your sounder provides them.

Show Depth Points is the honest one -- it shows exactly where you have data and where you don't. The heatmap and contours interpolate between readings, so they will look confident in places you never drove.

Colour and range

Setting Description
Color Scheme Colour palette used for the heatmap and contour layers. Choices: OceanBlue, Rainbow, RedYellow.
Contour Interval (ft) Depth difference between contour lines, in feet.
Depth Range Min (ft) Shallowest depth included in the color range.
Depth Range Max (ft) Deepest depth included in the color range.

The min and max set where the colour ramp starts and stops. Squeeze them down around the depths you actually care about and the shading gets far more readable -- a 0--30 ft range picks out bar edges that a 0--300 ft range flattens into one colour.

Contour Interval works the same way: a tight interval in shallow ground shows detail, a wide interval keeps a deep area from turning into a solid mess of lines.

Cloud sync (beta)

Setting Description
Enable Cloud Sync Back up your depth readings to the cloud and sync them across your devices.
Sharing Scope Who can see your synced depth data: just you, your group, or everyone. Choices: Private, Group Only, Public.
Show Community Depth Data Include depth readings shared by other BristolMaps users on your map.

Below those is a status line reading either All readings synced or "n readings pending upload", and a Sync Now button to push whatever is waiting.

Sharing scope decides who sees your ground

Private keeps synced data to your own account and devices. Group Only shares it with your fleet. Public shares it with everyone using Bristol Maps. Set this deliberately -- your recorded depth tracks tell people where you fish.

Beta

Cloud sync is labelled beta on the settings page. Treat it as a convenience, not as your only copy.

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