How to Use a GPS Chartplotter: Waypoints, Routes, and Tracks

A GPS chartplotter turns electronic charts into a live navigation display, but its real value comes from three core functions: waypoints, routes, and tracks. Used correctly, they help you plan a passage, stay on a safe line, and review what actually happened. Used carelessly, they can create a false sense of precision that leads to grounding, collision, or getting lost. This guide, part of an independent sailing reference and tools platform, explains how these functions work, how to use them in practice, and where their limits lie.

Main Explanation

What it is

In the context of this independent sailing reference and tools platform, How to Use a GPS Chartplotter: Waypoints, Routes, and Tracks is a structured guide for recreational sailors. It is not tied to a specific boat brand, sailing school, or equipment manufacturer. Its core purpose is to give sailors a clear, practical understanding of the three most important chartplotter functions so they can plan safer passages and make better decisions on the water.

A waypoint is a saved geographic position defined by latitude and longitude. A route is a sequence of two or more waypoints connected by straight legs that the chartplotter can guide you along. A track is a record of where your boat has actually been, typically shown as a dotted or solid line on the chart. These are distinct: a route is a plan, a track is history. Confusing them is a common and potentially dangerous mistake.

Why it matters

Recreational sailors face information overload, conflicting advice, and outdated resources. A chartplotter can display hundreds of data fields, alarms, and chart layers, but the manual may not explain which ones matter for a coastal passage. Forums and videos often skip the fundamentals or assume a specific brand. The stakes are high: a waypoint placed on a shoal, a route that cuts across a traffic separation scheme, or a track that is mistaken for a safe route can put the boat and crew at risk.

An independent reference platform matters because it organizes the core concepts without pushing a particular product. It helps sailors understand what the chartplotter is actually doing, what its data means, and how to cross-check it with paper charts, visual piloting, and official sources. That reduces the chance of trusting the screen too much or too little.

How it works

The platform structures chartplotter knowledge into four practical areas:

• Boat knowledge and reference: Understanding your chartplotter’s capabilities, chart formats, datum settings, and alarm options. This includes knowing whether your unit uses raster or vector charts and how often they are updated.
• Seamanship education: Placing chartplotter use within the wider framework of navigation, including COLREGS, pilotage, buoyage, and situational awareness. The chartplotter is a tool, not a substitute for looking out the window or understanding the rules of the road.
• Passage planning tools: Step-by-step methods for creating waypoints, building routes, checking for hazards, and setting cross-track error (XTE) alarms. This also covers how to use tides, currents, and weather information alongside the route.
• Decision-support features: Using tracks to review a passage, identify leeway or current set, and improve future plans. It also covers when to abandon a route and navigate manually.

In practice, a sailor might use the platform to learn how to set a waypoint at a safe turning point, build a route that avoids a charted wreck, and then review the recorded track to see how much the boat was set off course by current.

How to do it

Here is a practical walkthrough for planning and executing a short coastal passage using waypoints, routes, and tracks.

1. Confirm your position and chart settings. Power on the chartplotter and wait for a reliable GPS fix. Check that the chart datum matches your paper chart or official electronic chart, and that the display scale is appropriate for the area.
2. Create a waypoint at your departure point. Use the cursor or your current position to mark the starting location. Name it clearly, such as DEPART or HARBOR_ENT.
3. Add waypoints along the safe route. Move the cursor to each turning point, keeping clear of shoals, rocks, and traffic lanes. Place waypoints in safe water, not on hazards. Check each waypoint’s coordinates against a paper chart or official source.
4. Build the route. Connect the waypoints in order. Review the route leg by leg. Look for crossing hazards, shallow areas, and restricted zones. Adjust waypoints if needed.
5. Set alarms and activate the route. Set a cross-track error (XTE) alarm, typically 0.05 to 0.2 nautical miles depending on the width of the safe channel. Activate the route and confirm the chartplotter shows the correct course to steer and distance to the next waypoint.
6. Monitor and record a track. As you follow the route, watch your position, course over ground (COG), and speed over ground (SOG). Start a track recording. If the boat drifts off the route line, correct early rather than waiting for the alarm.
7. Review the track after arrival. Save the track and compare it with the planned route. Note where current or leeway pushed you off the line. Use that information to adjust future passage plans.

When not to do it

A chartplotter is not a substitute for professional training, a human weather router, or a certified marine surveyor. Do not rely solely on a chartplotter in these situations:

• In restricted visibility or heavy traffic: Use radar, AIS, sound signals, and visual lookouts. The chartplotter shows where you are, but not everything around you.
• When the chart data is outdated or unverified: If the electronic chart has not been updated or the area is poorly surveyed, treat the display as approximate. Cross-check with official paper charts and local knowledge.
• For critical weather decisions: A chartplotter may overlay weather data, but it is not a substitute for official marine forecasts, GRIB files interpreted by a trained sailor, or advice from a professional weather router.
• For boat condition or structural questions: A chartplotter cannot tell you if your rig, keel, or steering system is sound. For that, hire a certified surveyor or rigger.
• When learning basic navigation: If you do not understand chart symbols, buoyage, or dead reckoning, take a certified navigation course before relying on a chartplotter.

Visual

The following step sequence shows the core workflow for using waypoints, routes, and tracks on a GPS chartplotter. It is a simplified version of the full passage planning process.

1. Power on and confirm GPS fix. Wait for position accuracy to stabilize. Check chart datum and display scale.
2. Create a waypoint at the departure point. Name it clearly and verify coordinates.
3. Add waypoints along the safe route. Place each waypoint in safe water, clear of hazards and traffic lanes.
4. Build the route and review leg by leg. Check for shoals, wrecks, and restricted areas. Adjust as needed.
5. Set XTE alarm and activate the route. Choose an alarm distance appropriate for the channel width.
6. Monitor position, COG, and SOG while recording a track. Correct early if you drift off the route line.
7. Save and review the track after arrival. Compare actual track with planned route to learn from current and leeway.

Common Mistakes

Confusing a route with a track

A route is a plan; a track is a record of where you have been. If you follow a previous track thinking it is a safe route, you may repeat a deviation caused by current or poor steering. Consequence: you could run aground or enter a hazard. Correct approach: always build a route from current chart data and use tracks only for review and learning.

Placing a waypoint on a hazard

It is easy to drop a waypoint on a shoal, rock, or buoy without zooming in. Consequence: the chartplotter will guide you directly to the hazard. Correct approach: zoom in to the largest scale available, check the chart symbol, and place waypoints in safe water with a margin for error.

Ignoring chart datum and scale

If the chartplotter uses a different datum than your paper chart or official source, positions can be off by hundreds of meters. Using the wrong scale can hide small hazards. Consequence: you may think you are in safe water when you are not. Correct approach: confirm the datum matches, and always check the chart at the largest scale for your area.

Over-reliance on a single electronic source

Treating the chartplotter as the only navigation tool ignores the risk of power failure, GPS jamming, or chart error. Consequence: if the screen goes dark, you may be lost. Correct approach: keep paper charts, a handheld GPS, and basic plotting tools as backup. Cross-check with visual bearings and radar when possible.

Setting the XTE alarm too wide or not at all

A cross-track error alarm that is too wide may not sound until you are already in danger. No alarm means you may drift off the route without noticing. Consequence: grounding or collision in a narrow channel. Correct approach: set the XTE alarm to a distance that gives you time to correct, typically 0.05 to 0.2 nautical miles depending on the channel.

Using a phone or tablet as the primary chartplotter

Phones and tablets are not built for the marine environment. They can overheat, lose GPS signal, run out of battery, or be damaged by water. Consequence: loss of navigation at a critical moment. Correct approach: use a dedicated marine chartplotter as the primary system, and treat a phone or tablet as a backup only.

Safety Note

Digital navigation tools, including GPS chartplotters and independent reference platforms, must fit into a broader safety framework. They complement proper training, physical checks, and human judgment; they never replace them. Before every passage, cross-check critical data such as weather, tides, and navigation warnings with official sources, including national weather services and coast guard broadcasts. Never use a tablet or phone as your only navigation tool. Keep paper charts and a handheld compass aboard, and know how to use them. Take a certified safety and navigation course, and follow the International Regulations for Preventing Collisions at Sea (COLREGS) and all local maritime regulations. If you are unsure about your boat’s condition, hire a certified surveyor. If the weather is beyond your experience, consult a professional weather router. The chartplotter is a powerful aid, but the final decision always rests with the person at the helm.