C-MAP REVEAL Medium on SD / microSD Card – Complete Guide

Introduction

The C-MAP REVEAL Medium on SD / microSD card is digital marine charting designed for navigation with a marine GPS, chartplotter or navigation system compatible with C-MAP charts.

The C-MAP REVEAL range is distinguished by its detailed representation of the marine environment and by features designed to provide a clearer view of seabed conditions, coastlines, ports and other information useful for navigation. Depending on the covered area and chart reference, REVEAL charts may provide high-resolution bathymetric data, shaded relief, satellite or aerial imagery, as well as detailed plans of ports and marinas.

The Medium designation corresponds to a geographical coverage category. It is particularly suitable for navigators looking for chart coverage of a defined area for coastal or regional cruising, without necessarily requiring a wider geographical coverage.

The exact coverage always depends on the specific C-MAP REVEAL Medium chart reference. It is therefore essential to check the geographical area corresponding to the reference.

What is a C-MAP REVEAL Medium chart?

A C-MAP REVEAL Medium is a digital marine chart belonging to the C-MAP REVEAL range and supplied on an SD or microSD card, depending on the reference.

It allows various types of chart information required for planning and monitoring a voyage to be displayed on compatible navigation equipment.

Depending on the available data in the relevant area, the chart may show:

• coastlines and islands;

• depths and soundings;

• bathymetric contours;

• channels and navigable passages;

• ports and marinas;

• navigation aids;

• charted hazards and obstacles;

• selected special or regulated areas;

• detailed port information;

• high-resolution bathymetry;

• underwater relief shown using shaded relief.

The richness and type of data can vary from one region to another. The exact chart reference should therefore be considered the determining factor.

What does “Medium” mean in C-MAP?

The term Medium indicates an intermediate geographical coverage category within the relevant range.

However, “Medium” should not be interpreted as representing the same geographical area for every chart reference. Coverage depends on the cartographic area defined by C-MAP.

A C-MAP REVEAL Medium can therefore be particularly suitable for a navigator who regularly sails within a specific coastal or regional area.

For example, a sailor who mainly undertakes passages along one section of a coastline may be looking for coverage that is sufficiently extensive for their usual routes without requiring a chart covering a much larger area than necessary.

The objective is therefore to match:

• the actual sailing area;

• the C-MAP chart coverage;

• the navigation equipment;

• the required charting features.

Coastal and regional navigation

A C-MAP REVEAL Medium can be used for a variety of coastal navigation situations.

The navigator can display a general overview to plan a route and then increase the level of detail when approaching a coastline, island, channel or harbour.

A regional voyage may, for example, involve several stages between different ports. The chart can then be used to plan each section of the route and identify the main charted features along the passage.

It can be used to:

• plan a coastal route;

• view coastlines and islands;

• identify ports and marinas;

• examine charted depths;

• set waypoints;

• prepare a harbour approach;

• analyse selected coastal passages.

Shaded relief and seabed representation

One of the distinctive features of the C-MAP REVEAL range is its graphical representation of underwater relief.

Shaded relief makes it easier to visualise changes in the seabed. Rather than relying solely on numerical depth values, the navigator can also use a graphical representation of underwater terrain.

This can be particularly useful in areas with complex bathymetry, significant changes in depth or different forms of underwater relief.

Where available in the relevant area, high-resolution bathymetry can provide a more detailed representation of the seabed.

These data are useful for understanding the general configuration of an area, but they should not be confused with a real-time measurement.

Depths, soundings and bathymetry

A C-MAP REVEAL Medium can display charted depths and soundings.

This information helps the navigator understand the seabed configuration and check the charted depths along a planned route.

There is, however, a fundamental difference between:

• the depth shown on the digital marine chart;

• the depth measured instantaneously by the vessel's echo sounder.

The chart uses hydrographic data incorporated into the cartography. The echo sounder measures the depth directly beneath the vessel.

The navigator must also take into account the vessel's draught, tides, water-level variations, swell and local conditions.

Ports, marinas and coastal approaches

Coastal navigation often involves entering and leaving ports. Depending on the charted area, C-MAP REVEAL can provide detailed plans of ports and marinas.

These representations can help the navigator understand the layout of a harbour area and prepare an approach.

For example, a sailing yacht undertaking a coastal cruise can first prepare a general route and then examine in greater detail the ports that could be used as stopovers.

Depending on the area, the chart may provide information about basins, channels, harbour infrastructure and other charted features around the harbour entrance.

Satellite imagery and aerial photography

Depending on the coverage and chart reference, some C-MAP REVEAL charts may also include satellite imagery or aerial photography.

This information provides an additional visual representation of selected coastal areas.

It can be useful for:

• viewing a coastline;

• understanding the layout of an island;

• visually identifying certain harbour environments;

• complementing marine chart information;

• preparing a stopover.

The imagery available and its level of detail nevertheless depend on the relevant geographical area.

Example of using a C-MAP REVEAL Medium chart

Imagine a boat undertaking a multi-day coastal cruise in an area covered by a C-MAP REVEAL Medium chart.

The navigator first displays the general area to identify ports, islands and major passages. Several waypoints are then prepared for the different stages of the voyage.

As the vessel approaches the coast, the navigator increases the level of detail to examine:

• depths;

• bathymetric contours;

• channels;

• charted hazards;

• navigation aids;

• ports and marinas;

• underwater relief features.

This makes it possible to move progressively from a regional overview to a more detailed representation of the areas being navigated.

C-MAP REVEAL Medium on SD or microSD card

The charting is supplied on an SD or microSD card, depending on the reference.

The physical storage medium allows the data to be used on compatible equipment, but the fact that a GPS has an SD or microSD card slot does not automatically guarantee compatibility with the charting.

Before choosing a C-MAP REVEAL Medium chart, it is therefore important to check:

• the brand and model of the GPS or chartplotter;

• the device's compatibility with C-MAP;

• the exact chart reference;

• the geographical area covered;

• the SD or microSD format;

• the software or firmware version of the equipment, where required.

Compatibility should always be considered as a combination of the navigation equipment and the specific chart reference.

For sailing yachts and motorboats

The C-MAP REVEAL Medium can be suitable for different types of boats equipped with a compatible navigation system.

On a sailing yacht, it can be used to plan coastal routes, analyse charted depths and view passages between different areas.

On a motorboat, it can support coastal navigation, journeys between ports and marina approaches.

In both cases, the chart should be used with consideration of the vessel's characteristics and the prevailing navigation conditions.

A navigation aid, not an isolated source of information

Even highly detailed digital charting does not replace all the information required for safe navigation.

The navigator should also consult official nautical information, navigational warnings, local regulations, port information and weather forecasts.

Chart data must be interpreted according to their nature and date. In particular, the displayed depth is not a real-time measurement.

The vessel's echo sounder remains essential for measuring the actual depth beneath the hull.

How to choose a C-MAP REVEAL Medium chart

Choosing a C-MAP REVEAL Medium chart should begin by defining the usual navigation area.

This area should then be compared with the exact coverage of the C-MAP reference being considered.

The main criteria are:

• geographical coverage;

• exact C-MAP REVEAL reference;

• required coverage level;

• GPS or chartplotter model;

• C-MAP compatibility;

• SD or microSD format;

• features available in the relevant area;

• available update options.

The term Medium therefore does not automatically mean worldwide coverage, or even complete coverage of an entire sea or country. Only the specific chart reference determines the actual geographical area covered.

Conclusion

The C-MAP REVEAL Medium on SD / microSD card is digital marine charting suitable for coastal and regional navigation within the area corresponding to its specific chart reference.

It benefits from the characteristics of the REVEAL range, including detailed seabed representation, shaded relief, high-resolution bathymetry in selected areas and, depending on the available data, satellite imagery, aerial photography and detailed information about ports and marinas.

When choosing the correct C-MAP REVEAL Medium chart, the key criteria are the navigation area, exact chart coverage, GPS or chartplotter compatibility and SD or microSD format.

FAQ – C-MAP REVEAL Medium on SD / microSD Card

What is a C-MAP REVEAL Medium chart?

It is a digital marine chart from the C-MAP REVEAL range designed for use on a compatible marine GPS, chartplotter or navigation system.

What does “Medium” mean for a C-MAP REVEAL chart?

Medium identifies a geographical coverage category within the range. The exact area covered depends on the specific C-MAP chart reference.

What is a C-MAP REVEAL Medium chart used for?

It allows digital marine charting to be displayed, the vessel's position to be monitored, routes to be planned, waypoints to be set and available chart information to be viewed within the covered area.

Does C-MAP REVEAL Medium display depths?

Yes. The available data may include soundings, depths and bathymetric contours depending on the charted area.

Does C-MAP REVEAL Medium display underwater relief?

The REVEAL range provides underwater relief representation through shaded relief and, in selected areas, high-resolution bathymetric data.

Are C-MAP depths measured in real time?

No. The displayed depths correspond to the chart data. Real-time depth measurement is provided by the vessel's echo sounder.

Does C-MAP REVEAL Medium provide port and marina plans?

Depending on the area and available data, REVEAL charting can provide detailed plans of ports and marinas.

Does C-MAP REVEAL Medium provide satellite imagery?

Depending on the chart reference and covered area, some REVEAL data may include satellite imagery or aerial photography.

Does a C-MAP REVEAL Medium chart work with all marine GPS units?

No. The GPS or chartplotter must be compatible with C-MAP charting and with the relevant chart reference.

Will a C-MAP REVEAL Medium chart work in any microSD card reader?

No. The microSD format is only the physical storage medium. Electronic compatibility depends on the navigation equipment and the chart being used.

Is C-MAP REVEAL Medium suitable for sailing yachts?

Yes, provided the navigation system is compatible. It can be used for planning and monitoring coastal navigation.

Is C-MAP REVEAL Medium suitable for motorboats?

Yes, subject to compatibility with the GPS or chartplotter. It can be used for coastal navigation and journeys between ports and marinas.

What area does a C-MAP REVEAL Medium chart cover?

Coverage depends on the exact chart reference. The term Medium alone does not identify a specific geographical area.

How do I choose the correct C-MAP REVEAL Medium chart?

Check the navigation area, exact chart reference, geographical coverage, GPS or chartplotter model, C-MAP compatibility and SD or microSD format.

Does a C-MAP REVEAL Medium chart replace official nautical information?

No. It is an electronic navigation aid and should be used together with official nautical information, navigational warnings, local regulations and available weather information.