NOAA’s Chart Rescheming Project: Modernizing the Foundation of Safe Navigation

Navigating the coastal waters of the United States has always relied on the most accurate, up-to-date, and user-friendly nautical charts. For over a century, mariners have trusted NOAA’s paper and electronic charts as their guides, whether piloting a recreational sailboat, managing a commercial vessel, or exploring new waters. In recent years, NOAA has undertaken an ambitious project known as "rescheming" to modernize its chart suite. This initiative will deliver a more consistent, seamless, and adaptable set of navigational products—an undertaking that has far-reaching implications for anyone who spends time on the water.  Until this rescheming project is complete, we at Frugal Navigator will be doing our best to adapt and meet the challenges of constant changes to NOAA chart data.

Why Is NOAA Rescheming Its Charts?

NOAA’s traditional paper chart suite (known as Raster Navigational Charts, or RNCs) and its first-generation Electronic Navigational Charts (ENCs) have been mainstays of American navigation. However, these charts have accumulated over many decades and were created using various scales, formats, and standards reflective of the technology available at the time. As a result, mariners today encounter a patchwork of overlapping, sometimes inconsistent charts, with varying levels of detail and coverage.

This patchwork made sense in the era of paper-only navigation, but modern mariners increasingly depend on digital charting systems and expect a seamless experience—where chart coverage is uniform, data layers are reliable, and new features (like custom chart creation) are supported.

The rescheming project is NOAA’s solution. Its goals are to:

Modernize the foundational data by transitioning from RNCs to a unified, more logically organized set of ENCs.

Eliminate unnecessary overlaps and gaps in chart coverage.

Organize charts into “usage bands” (standardized scale ranges for different types of navigation) to match international standards.

Support new tools and technology such as the NOAA Custom Chart Tool, which lets users create their own paper charts from ENC data.

By rescheming, NOAA is essentially redrawing its chart coverage—standardizing scales, boundaries, and data content so that both digital and printed charts are easier to use, maintain, and update.

    How Does the Rescheming Project Work? Understanding Usage Bands

A key part of rescheming is reorganizing NOAA ENCs into “usage bands.” These bands group charts by intended use and scale, and the system is aligned with the international S-57 standard used worldwide:

1. Overview (Usage Band 1): For planning long ocean passages (very small scale, broadest coverage).
2. General (Usage Band 2): For coastal navigation and open-sea routes.
   
3. Coastal (Usage Band 3): For approaching coastline and passage along the coast.
   
4. Approach (Usage Band 4): For navigating near harbors or entering coastal waters.
   
5. Harbor (Usage Band 5): For maneuvering in and around harbors and anchorages.
6. Berthing (Usage Band 6): For dockside and marina movement, requiring the largest scale and greatest detail.
   
   

Each reschemed ENC covers a specific region at a single, logical scale. The chart boundaries are adjusted so that they line up logically with adjacent charts, greatly reducing confusion and overlap. This also means every mariner knows exactly which chart to use for a given area and level of detail.

Why Does Rescheming Matter? The Case of the Custom Chart Tool

One of the most exciting developments in NOAA’s modernization efforts is the **NOAA Custom Chart Tool**. This tool allows mariners to generate their own printable charts, tailored to specific routes, areas, and preferences, using the most current ENC data as a foundation.

However, this tool’s effectiveness depends on the availability of fully reschemed ENC coverage. If an area has not yet been reschemed, the data may be incomplete, inconsistent, or not available in the format needed for a seamless custom chart. This can cause:

Gaps in chart coverage where no reschemed data exists.

Jarring differences in scale or quality between adjacent chart sections.

Missing features or outdated information in some areas.

For mariners who rely on paper charts as a primary or backup navigation method (something I always recommend!), these inconsistencies can pose real challenges. Imagine planning a passage only to find that your printed chart lacks detail for a critical harbor, or that your digital backup doesn’t match the surrounding coverage.

Until rescheming is complete, it’s important for mariners to:

• Check existing NC coverage before planning a voyage.
•  Use NOAA's online resources to confirm the rescheming status of their intended route.
•  Be prepared for possible gaps and carry backup charts when venturing into less well-documented areas.

Challenges and Opportunities Ahead

Rescheming an entire nation’s nautical charts is a major technical and logistical challenge. NOAA’s chart-makers must:

• Reconcile decades of data collected using different standards.
• Redefine chart boundaries from scratch, ensuring seamless transitions.
  
• Update hydrographic data where needed, especially in fast-changing environments like shifting coastlines, shoals, or new ports.
  
• Communicate changes to mariners, chart software developers, and publishers.

At the same time, the payoff is tremendous. The new, reschemed ENC suite will enable:

• Faster updates when new data is available, since changes propagate through the digital charts much more efficiently than in the old paper system.
  
• Custom charts that are as detailed, current, and user-friendly as possible.
• Greater safety, since mariners will always have access to the latest and most consistent information, whether they use a chart plotter, a mobile app, or a good old-fashioned paper chart.
  

Looking to the Future

The end of the rescheming process will mark a new era in U.S. navigation. NOAA’s chart suite will be easier to use, more reliable, and more future-proof than ever before. As someone who cherishes both the tradition of paper charts and the promise of modern digital navigation, I see this as a win for all mariners.

Until the transition is complete, my advice is to stay engaged with the process—explore the new reschemed charts as they are released, try out the Custom Chart Tool, and always prepare for the unexpected by carrying up-to-date paper charts as a backup. After all, the best navigators are those who can adapt to new tools while respecting proven traditions.