A marine GPS chartplotter can be a simple navigation display or the control center for an entire boat. The right choice depends less on the logo on the bezel and more on how the unit fits your helm, cruising area, transducer, radar, autopilot and future upgrade plans.
What does a marine GPS chartplotter do?
A chartplotter combines satellite positioning with electronic marine charts. Modern multifunction displays can also show sonar, radar, AIS targets, engine data, cameras, weather and autopilot controls when connected to compatible equipment. Garmin describes networkable chartplotters as integrated displays that can act as a central hub for connected vessel systems.
That integration is useful, but it also makes compatibility the most important part of the buying decision. A capable display is only valuable when it works with the sensors and charts you actually use.
Marine chartplotter screen-size guide
| Screen size | Usually suits | What to consider |
|---|---|---|
| 5–7 inches | Kayaks, small center consoles and secondary stations | Compact and efficient, but split-screen views can feel crowded. |
| 9 inches | Small and midsize fishing boats | A useful balance of visibility, installation space and cost. |
| 10–12 inches | Offshore fishing, cruising and multi-function use | Better for chart, sonar and radar combinations on one screen. |
| 16 inches and larger | Large helms, yachts and multi-display systems | Check dash dimensions, viewing distance, power and network design. |
Measure the usable dash opening, not the old display’s diagonal size. Leave room for the mounting hardware, cable bends, ventilation and access for service. A flush-mounted unit often needs considerably more clearance behind the panel than its visible dimensions suggest.
Seven features to compare before buying
1. Chart coverage and update path
Confirm the exact coastal, inland or regional map coverage included with the unit. Check whether updates require an app, memory card or computer and whether premium chart layers need a subscription. Updated chart data remains important even when the display hardware is unchanged.
2. Touchscreen, keys or hybrid controls
Touchscreens are quick for panning and menu navigation. Physical keys can be easier in rain, spray, cold conditions or rough water. Hybrid controls provide both options but require more bezel space.
3. Sonar and transducer compatibility
“Sonar capable” does not mean every transducer will work. Match the connector, supported frequencies, CHIRP ranges, side/down imaging technology, maximum power and any required sonar module. If you already own a transducer, record its full model number before selecting the display.
4. Radar, AIS and autopilot integration
Radar scanners and advanced autopilot controls are often ecosystem-specific. AIS data is more broadly shared, but connection type still matters. Confirm whether each device uses NMEA 2000, NMEA 0183, Ethernet or a proprietary network and whether adapters are required.
5. Network ports and future expansion
Count the ports needed today and reserve capacity for planned upgrades. A larger system may require a network switch, backbone components, additional power distribution and software updates across several devices.
6. Brightness, viewing angle and installation location
A screen that looks excellent indoors may be difficult to read in direct sun. Compare brightness and viewing angles, especially when the operator is standing or the display will be seen from different seats. For open helms, verify the manufacturer’s environmental rating and mounting guidance.
7. Charts for US, Canadian and Australian waters
Do not assume a model sold internationally contains the same preloaded charts in every package. Verify the region in the exact part number. This is particularly important when ordering equipment for use outside the seller’s home country.
Garmin vs Raymarine vs Lowrance vs Simrad
There is no universal winner. The strongest choice is normally the ecosystem that matches the rest of the boat:
- Garmin: often considered when owners want broad GPSMAP integration with compatible Garmin radar, sonar, autopilot and marine networking.
- Raymarine: a natural candidate for vessels already using Raymarine radar, Evolution autopilot, thermal imaging or Axiom displays.
- Lowrance: frequently selected for fishing-focused sonar and trolling-motor integration.
- Simrad: commonly evaluated for offshore, sportfishing and integrated helm applications.
Compare exact model and accessory compatibility rather than relying on brand-level assumptions.
Chartplotter buying checklist
- Measure the helm opening and viewing distance.
- Write down the full model numbers of existing sensors and displays.
- Confirm included chart region and update method.
- Choose the transducer and sonar requirements.
- Check radar, AIS, autopilot and engine-data compatibility.
- Confirm power consumption, connector clearance and network parts.
- Review warranty coverage for the destination country.
Explore chartplotters and GPS equipment by brand, display size and application.
Frequently asked questions
Is a 7-inch or 9-inch chartplotter better?
A 7-inch unit saves dash space, while a 9-inch display generally makes split-screen navigation and sonar easier to read. The correct size depends on viewing distance and available helm space.
Can any transducer connect to any chartplotter?
No. Connector, frequency, power and sonar technology must match. An adapter may solve a connector difference but cannot add unsupported sonar capability.
Do I need NMEA 2000?
Not every installation needs it, but NMEA 2000 is useful for sharing compatible engine, heading, depth, wind, AIS and other sensor data across a vessel network.
Can a chartplotter replace safe navigation practices?
No. Electronic equipment is a navigation aid. Operators remain responsible for maintaining a proper lookout, using current official information and operating safely.
Continue planning your system: read our marine radar buying guide and trolling motor sizing guide.
Technical reference: Garmin chartplotter technology overview.
