NGA Pacific Ocean Nautical Chart

The Pacific Ocean is the largest ocean in the world. It stretches from the west coast of the Americas to Asia and Oceania and includes thousands of islands, archipelagos and maritime areas with very different characteristics. Transpacific crossings, round-the-world sailing, yacht delivery, offshore navigation, exploration of Pacific archipelagos, or approaches to the American, Japanese and Australian coasts: each route requires appropriate charts and scales.

An NGA Pacific Ocean nautical chart provides a cartographic representation suitable for international and offshore navigation. Published by the National Geospatial-Intelligence Agency (NGA), these charts cover many areas of the Pacific, from major oceanic routes to selected coastal and port areas.

Nautic Way Maritime Bookshop therefore offers a selection of NGA nautical charts for the Pacific Ocean, suitable for planning a Pacific crossing, navigation between the United States and Asia, a route between Polynesia and Australia, or navigation within Pacific archipelagos.

What is an NGA Pacific Ocean nautical chart used for?

An NGA Pacific Ocean nautical chart is primarily used to plan and conduct international navigation across an exceptionally vast maritime area.

It can be used to:

• plan a transpacific crossing;

• plan a route between the Americas and Asia;

• prepare a voyage between the Americas and Polynesia;

• plan a route between French Polynesia, Fiji, Tonga and New Zealand;

• prepare a voyage towards Australia or New Caledonia;

• study routes between Asia, Japan and Oceania;

• plan a round-the-world sailing voyage;

• prepare a long-distance yacht delivery;

• obtain an overall view before switching to more detailed coastal charts.

For ocean navigation, a small-scale chart makes it possible to visualise a very large part of the route at once. It helps determine distances, possible stopovers, major land areas and alternative routing options.

Cartographic coverage adapted to the vastness of the Pacific

The Pacific contains extremely diverse maritime environments. A route may cross several thousand nautical miles of open ocean before reaching an island group or coastline.

NGA charts cover areas including:

• the North Pacific;

• the South Pacific;

• the central Pacific;

• the western Pacific;

• the eastern Pacific;

• the west coast of North America;

• the west coast of South America;

• Japan and East Asia;

• Australia and Oceania;

• Micronesian and Melanesian archipelagos;

• Polynesia and Pacific islands.

The choice of chart must always take into account the exact route, geographical area and required scale.

An ocean-scale chart does not meet the same requirements as a chart intended for port approaches or navigation among reefs.

NGA nautical chart for crossing the Pacific

An NGA nautical chart for a Pacific crossing is particularly useful during the route-planning stage.

A transpacific crossing may link, for example:

• California and Hawaii;

• Hawaii and French Polynesia;

• Polynesia and the Cook Islands;

• the Cook Islands and Tonga or Fiji;

• Fiji and New Caledonia;

• New Caledonia and Australia;

• Japan and North America;

• Southeast Asia and Australia.

These routes require a very broad geographical overview before working on the individual coastal stages.

An ocean-scale chart makes it possible to establish the general route, assess distances and identify the areas where more detailed charts will subsequently be required.

Navigation in the South Pacific

The South Pacific is particularly important for sailors undertaking a trade-wind route around the world.

French Polynesia, the Cook Islands, Tonga, Samoa, Fiji, Vanuatu, New Caledonia and New Zealand form a vast group of destinations separated by long ocean passages.

In these areas, navigators must take into account:

• the enormous distances between archipelagos;

• coral reefs;

• passes;

• lagoons;

• shoals;

• low-lying islands that can sometimes be difficult to identify;

• tropical weather conditions;

• cyclone-prone areas;

• currents and local effects.

An NGA South Pacific nautical chart provides an essential overall view for route planning. It should then be supplemented with larger-scale charts for approaches to islands, reefs, passes and ports.

Polynesia, Melanesia and Micronesia

Pacific archipelagos represent a particularly complex charting environment.

Navigation around tropical islands may require a rapid transition from an ocean-scale chart to a much more detailed coastal chart.

In an archipelago, the navigator must be able to accurately identify:

• reefs;

• passages through barrier reefs;

• shoals;

• channels;

• anchorages;

• lights and aids to navigation;

• isolated dangers;

• depths.

NGA charts can therefore provide an initial planning framework, but they do not replace the large-scale charts required for approaches.

This distinction between ocean navigation, coastal navigation and port approaches is essential when building a coherent chart portfolio.

Example: navigation around the Marshall Islands

Some NGA charts cover particularly remote areas of the Pacific.

For example, NGA 81715 – Kwajalein Atoll covers Kwajalein Atoll in the Marshall Islands at a scale of 1:75,000, in the coastal chart category. This scale provides considerably more detail than charts intended for ocean planning.

This example illustrates the importance of choosing the appropriate scale: a chart intended for an atoll or coastal area does not serve the same purpose as a chart used to plan a passage of several thousand nautical miles.

Example: the West Coast of the United States

NGA charting also covers selected coastal areas of the American Pacific coast.

For example, NGA 18722 – Point Arguello to Purisima Point is a 1:25,000-scale chart covering a coastal area of California. It therefore provides a very different level of detail from an ocean-scale chart.

This type of chart may be used during a coastal stage of a voyage, whereas a smaller-scale chart would have been used to plan the overall Pacific crossing.

NGA Pacific nautical charts: cartographic information

Depending on the scale and geographical area, an NGA chart may show a wide range of information required for navigation:

• depths and soundings;

• seabed characteristics;

• reefs and shoals;

• wrecks;

• isolated dangers;

• channels;

• islands and islets;

• ports and maritime infrastructure;

• lighthouses and lights;

• buoys and other aids to navigation;

• shipping routes;

• regulated areas;

• military or special areas;

• geographical and hydrographic information.

Chart symbols and conventions allow navigators to quickly identify essential information.

Accurate interpretation of the chart nevertheless requires consultation of the legend, chart notes and any additional information associated with the relevant edition.

Which scale should you choose for a Pacific nautical chart?

Scale is fundamental.

For a Pacific crossing, a small-scale chart can represent an extremely large geographical area. It is primarily used for general route planning.

By contrast, a large-scale chart is required to:

• approach an island;

• transit a pass;

• navigate within a lagoon;

• enter a port;

• clear a reef;

• reach an anchorage;

• navigate in an area containing numerous hazards.

It is therefore preferable to think in terms of a chart portfolio rather than a single chart.

A serious voyage plan may combine:

1. one or more ocean-scale charts for the crossing;

2. regional charts for the different stages;

3. coastal charts for approaches;

4. harbour charts or detailed plans where necessary.

NGA paper charts and electronic navigation

GPS, chartplotters and other electronic systems have transformed modern navigation. They do not, however, eliminate the value of paper charts.

During a Pacific crossing, a paper chart makes it possible to:

• immediately visualise the complete route;

• work at a very large geographical scale;

• plan the different stages;

• visualise distances;

• identify possible diversion routes;

• maintain a navigation reference independent of electronic equipment.

It also provides important redundancy in the event of a power failure, screen failure or problem affecting the electronic navigation system.

Paper charts should nevertheless be used together with appropriate navigation methods and current navigational information.

NGA charts and national hydrographic offices

Throughout the Pacific, many countries have their own hydrographic offices.

Depending on the area being navigated, sailors may therefore use:

• NGA charts for international and offshore navigation;

• national hydrographic charts;

• large-scale coastal charts;

• harbour plans;

• sailing directions;

• weather information;

• Notices to Mariners.

This complementary approach is particularly important in areas containing reefs, narrow passes or complex port approaches.

An NGA Pacific Ocean nautical chart should therefore not be regarded as a universal chart replacing every other scale.

Weather and navigation in the Pacific

Navigation in the Pacific also requires particularly careful weather planning.

Depending on latitude and season, sailors may encounter:

• trade winds;

• tropical depressions;

• cyclones;

• weather fronts;

• long-period swell;

• significant changes in wind conditions;

• ocean currents.

In the South Pacific, the cyclone season directly affects route planning between the archipelagos.

The nautical chart provides the geographical framework for the route, but it must be combined with weather forecasts, current information and maritime safety data to determine the route actually followed.

Who are NGA Pacific Ocean nautical charts for?

NGA Pacific Ocean nautical charts may be used by:

• sailors planning a transpacific crossing;

• world cruisers;

• skippers and yacht delivery crews;

• professional mariners;

• commercial vessels;

• offshore fishermen;

• maritime schools and training centres;

• crews navigating Pacific archipelagos;

• sailors planning routes between the Americas, Oceania and Asia.

They are particularly relevant for voyages requiring an international, large-scale charting overview.

NGA Pacific charts: charting for major maritime routes

The main advantage of NGA charting in the Pacific is its ability to provide a coherent representation of extremely large maritime areas.

It allows the navigator to move progressively:

from the ocean-scale overview → to the regional route → to coastal navigation → to the port approach.

This approach is particularly important for a yacht undertaking a round-the-world voyage or a transpacific crossing.

For example, a sailor leaving California for French Polynesia needs charting that first allows the ocean passage to be planned, followed by more detailed charts for approaching the archipelagos.

Nautic Way Maritime Bookshop expertise

Nautic Way Maritime Bookshop specialises in nautical charts and maritime documentation, with more than 20,000 references.

For navigation in the Pacific, choosing a chart primarily depends on three factors:

• the geographical area;

• the type of navigation;

• the required scale.

This approach makes it possible to distinguish between a chart intended for an ocean crossing and one intended for coastal navigation within an archipelago or for a port approach.

Conclusion: preparing a Pacific crossing with the right charts

The NGA Pacific Ocean nautical chart is an important tool for planning international navigation, transoceanic crossings and long-distance voyages.

It provides coverage of areas as diverse as the North Pacific, South Pacific, Polynesia, Micronesia, Melanesia, the American coasts, East Asia and Australia.

For optimum use, it should form part of a chart portfolio combining several scales and, depending on the route, national hydrographic charts, coastal plans, sailing directions and weather information.

For a Pacific crossing, the right charting is not necessarily a single chart: it is a coherent set of charts adapted to each stage of the voyage.

FAQ – NGA Pacific Ocean Nautical Chart

Which NGA nautical chart should I choose for crossing the Pacific?

The choice depends on the planned route. A small-scale chart is used to plan the ocean crossing, while more detailed regional and coastal charts are required when approaching islands, reefs and ports.

Is there an NGA chart covering the entire Pacific Ocean?

NGA charts are organised according to different geographical areas and scales. Several references are therefore generally required to cover a long crossing and its different stages.

Which NGA chart should I use for a California–French Polynesia crossing?

The chart used to plan the transpacific crossing should be distinguished from the charts required for the approach to French Polynesia. Chart coverage should be selected according to the exact route and required scale.

Which NGA nautical chart should I use for sailing in Polynesia?

For navigation in Polynesia, charts with sufficient detail for approaches to islands, reefs, passes and lagoons should be prioritised. An ocean-scale chart alone does not provide the level of detail required for all coastal manoeuvres.

Do NGA charts cover the Marshall Islands?

Yes. The NGA portfolio includes charts covering areas of the Marshall Islands. For example, NGA 81715 covers Kwajalein Atoll at a scale of 1:75,000.

Are there NGA charts of the West Coast of the United States?

Yes. Some NGA charts cover coastal areas of the American Pacific coast. NGA 18722, for example, covers the area from Point Arguello to Purisima Point in California at a scale of 1:25,000.

Is an NGA chart sufficient for a Pacific crossing?

No. It is one component of the charting strategy. A complete crossing generally requires several scales and, depending on the area, national charts, coastal charts, harbour plans and additional nautical publications.

Do I need a paper chart for a Pacific crossing?

Paper charts remain particularly useful for ocean passage planning and provide valuable redundancy in the event of electronic system failure. They should form part of a comprehensive navigation strategy.

What is the difference between an NGA chart and a national hydrographic chart?

NGA provides international coverage particularly useful for ocean routes and selected international areas. National hydrographic offices generally produce charts specifically adapted to their own waters, particularly for coastal and port approaches.

Are NGA Pacific charts suitable for round-the-world sailors?

Yes. They can be particularly useful for planning the major stages of a round-the-world voyage, including crossings between the Americas, Polynesia, Australia and Asia. They should nevertheless be supplemented by charts appropriate to each stopover and coastal approach.