C-MAP Discover Medium on SD / microSD Card

Introduction

The C-MAP Discover Medium on SD / microSD card is a digital marine chart designed for use with C-MAP-compatible electronic navigation equipment. It allows detailed chart information to be displayed on a marine GPS, GPS chartplotter or compatible navigation system, making it possible to plan and monitor a route at sea or in the coastal areas covered by the selected chart reference.

The C-MAP Discover Medium range provides an intermediate level of geographical coverage. It is suitable for boaters looking for sufficiently extensive digital chart coverage for a specific region, without necessarily requiring the very broad coverage offered by Wide or Extra Large charts.

The chart may be supplied in SD or microSD format, depending on the specific C-MAP reference and the navigation equipment being used. It is therefore essential to check both the geographical coverage and compatibility with the GPS or chartplotter before selecting a chart.

What is a C-MAP Discover Medium?

A C-MAP Discover Medium is a digital marine chart designed for navigation equipment compatible with C-MAP data.

The term Medium mainly refers to the geographical coverage provided by the chart reference. It does not mean that the chart contains less detailed information within its coverage area. It primarily indicates a geographical area that is more targeted than that of a Large, Wide or Extra Large chart.

Depending on the specific reference, the digital chart data may include:

• coastlines and shoreline information;

• depths and available soundings;

• bathymetric contours;

• channels and navigable passages;

• ports and harbour facilities;

• marinas and anchorage areas;

• navigation aids;

• certain hazards and navigational features;

• information used for route planning.

The exact data and coverage depend on the specific C-MAP chart reference. A Discover Medium chart should therefore not be considered a universal or worldwide chart.

What is a C-MAP Discover Medium on SD or microSD used for?

A C-MAP Discover Medium digital marine chart allows chart information to be used directly on compatible electronic navigation equipment.

It can be used to:

• plan coastal navigation;

• display a navigation area on the GPS screen;

• monitor the vessel's position;

• create waypoints and routes;

• identify ports and harbour approaches;

• view available depth information;

• analyse an area before navigation;

• modify a route according to the conditions encountered;

• access digital chart coverage for a defined geographical region.

The main advantage of chart data stored on an SD or microSD card is its direct use with compatible marine electronics. The card contains the data required to display the digital chart on the relevant navigation system.

C-MAP Discover Medium for coastal navigation

The Discover Medium range is particularly relevant for coastal or regional navigation when a vessel regularly operates within a defined geographical area.

For example, a boat cruising regularly along a particular coastline may need chart coverage for several ports, anchorages and navigation areas around its usual cruising grounds.

A Medium coverage can then provide a useful balance between:

• a Local chart that may be too limited;

• a much broader chart covering large areas that may never be used.

It can also be suitable for recreational boating, coastal cruising, fishing or regional voyages, subject to the exact coverage of the selected reference.

Depths, soundings and bathymetry

C-MAP digital charting can display information relating to depths and bathymetry available within the chart data.

This information is particularly useful when planning a route, identifying shallower areas and analysing the approach to a port or anchorage.

However, it is important to distinguish charted information from real-time measurements made by the vessel's depth sounder.

The digital chart represents cartographic information based on the available data for the relevant area. It is therefore not an instantaneous measurement of the water depth beneath the vessel.

During navigation, charted depth information should be interpreted together with other available information, including tides, water levels, weather conditions, vessel draft, currents and the navigator's observations.

SD or microSD: what is the difference?

The physical format depends on the C-MAP reference and the navigation equipment for which the chart is intended.

Available formats may include:

• SD cards;

• microSD cards;

• microSD cards supplied with an adapter for use in certain SD card readers.

It is important not to consider only the physical size of the card.

A microSD card slot does not automatically mean that every microSD chart will be compatible with the equipment. Compatibility also depends on the C-MAP system supported, the GPS or chartplotter model, its generation and sometimes its software version.

Before use, it is therefore recommended to check:

• the exact brand and model of the GPS or chartplotter;

• the supported charting system;

• the accepted card format;

• the C-MAP reference;

• the geographical coverage;

• any applicable update requirements.

C-MAP Discover Medium: intermediate regional coverage

One of the advantages of the Discover Medium range is its position between highly localised coverage and broader geographical coverage.

For a navigator who wants chart coverage for a regional area without using a worldwide or very extensive chart, a Medium chart may meet a targeted navigation requirement.

For example, a chart may be suitable for a navigator who regularly undertakes:

• coastal trips;

• cruises within a specific maritime region;

• passages between several nearby ports;

• navigation around an island group;

• seasonal cruising within the same geographical area.

The exact coverage nevertheless remains essential. Two different C-MAP Discover Medium references may correspond to two completely different geographical areas.

What is the difference between C-MAP Local, Medium, Large and Extra Large?

The terms Local, Medium, Large, Wide and Extra Large are used to distinguish, among other things, the geographical coverage offered by different C-MAP references.

In general terms:

• Local: targeted geographical coverage around a specific area;

• Medium: broader regional coverage;

• Large: extensive geographical coverage;

• Wide: even broader coverage depending on the reference;

• Extra Large: very extensive geographical coverage.

This hierarchy should nevertheless be treated as a general indication. It does not mean that an Extra Large chart automatically covers the entire world, or that a Medium chart necessarily covers every coastline within a region or continent.

When selecting a digital marine chart, the exact chart reference and its geographical coverage are therefore more important than the Medium, Large or Extra Large designation alone.

Is a C-MAP Discover Medium suitable for offshore navigation?

A C-MAP Discover Medium can be perfectly suitable for coastal or regional navigation when its coverage corresponds to the planned route.

However, the term Medium should not be interpreted as guaranteeing coverage suitable for all offshore or transoceanic navigation.

For an ocean crossing, the navigator should check the coverage of each area along the route and ensure that the required chart data are available on the equipment being used.

A long-distance passage also requires appropriate chart planning, with consistent coverage of the complete route and its coastal approach areas.

Planning a voyage with a C-MAP Discover Medium

A digital marine chart is not only useful for following a route once at sea. It is also an important route-planning tool.

Before departure, the navigator can:

1. identify the general cruising area;

2. check the chart coverage;

3. locate available ports and shelters;

4. examine depths and seabed configuration;

5. create waypoints;

6. build a route;

7. identify special or restricted areas;

8. check different approach options;

9. verify compatibility between the chart and the GPS;

10. prepare an alternative route in case conditions change.

This preparation is particularly useful for coastal cruising, where several routes may be considered depending on weather, wind, currents or vessel constraints.

Check compatibility before use

A C-MAP Discover Medium on SD or microSD card is not necessarily compatible with every marine GPS equipped with a card reader.

Electronic compatibility must be checked carefully.

In particular, you should verify:

• the chartplotter model;

• the equipment brand and generation;

• C-MAP compatibility;

• the accepted card type;

• the chart reference;

• the system software version;

• any applicable activation or update requirements.

This check is essential because the fact that a chart is supplied on an SD or microSD card does not by itself guarantee that it will work with a particular navigation device.

Conclusion

The C-MAP Discover Medium on SD / microSD card is a digital marine chart designed for GPS units, chartplotters and navigation systems compatible with C-MAP. Its main characteristic is its intermediate geographical coverage, making it particularly suitable for coastal navigation and regional cruising.

Depending on the reference, it can provide chart information such as depths, soundings, bathymetric contours, ports, channels and navigation aids.

The choice of a C-MAP Discover Medium should nevertheless always be based on three essential criteria: the geographical area covered, the exact C-MAP reference and compatibility with the navigation equipment.

FAQ – C-MAP Discover Medium on SD / microSD

What is a C-MAP Discover Medium?

A C-MAP Discover Medium is a digital marine chart offering intermediate geographical coverage for GPS units, chartplotters and navigation systems compatible with C-MAP.

What is a C-MAP Discover Medium on SD used for?

It allows digital marine charting to be displayed on compatible equipment, including for route planning, position monitoring, viewing depths and navigating within the covered area.

Is a C-MAP Discover Medium available on microSD?

Depending on the C-MAP reference, the chart may be supplied on SD or microSD. The format provided for the specific reference and its compatibility with the navigation equipment should be checked.

What is the difference between C-MAP Discover Medium and Discover Large?

The main difference concerns the geographical extent of the coverage. A Discover Large generally covers a larger area than a Discover Medium. The exact coverage should be checked for each reference.

Is a C-MAP Discover Medium a worldwide chart?

No. A C-MAP Discover Medium should not be considered a worldwide chart. Its coverage depends on the specific geographical reference.

Is a C-MAP Discover Medium suitable for coastal navigation?

Yes. It can be particularly suitable for coastal navigation and regional cruising when the chart coverage corresponds to the planned route.

Does a C-MAP Discover Medium show depths?

C-MAP chart data can include soundings, depths and bathymetric information, depending on the area and specific chart reference.

Are C-MAP depths measured in real time?

No. Charted depth information does not replace real-time measurements made by the vessel's depth sounder. It should be interpreted together with navigation conditions and water levels.

Does a C-MAP Discover Medium work with all GPS units?

No. It must be used with equipment compatible with the C-MAP system and the specific chart reference. The exact GPS or chartplotter model must be checked.

Will a GPS with a microSD slot automatically accept a C-MAP microSD chart?

No. Having a microSD slot does not guarantee compatibility. The charting system, equipment model and C-MAP reference must also be compatible.

What is the difference between C-MAP Local and Discover Medium?

Local coverage is generally more geographically targeted, while Medium corresponds to a broader area. The exact coverage nevertheless depends on each individual reference.

Is a C-MAP Discover Medium suitable for a transoceanic crossing?

Not necessarily. The navigator must verify that the selected reference covers all the areas required for the crossing. The term Medium does not guarantee offshore or worldwide coverage.

How can I check whether a C-MAP Discover Medium is compatible with my GPS?

Check the exact GPS or chartplotter model, its compatible charting system, the accepted SD or microSD format, the C-MAP reference and, where necessary, the equipment's software version.