Coast Survey improves access to data on thousands of wrecks and obstructions

Knowing the locations of shipwrecks and other obstructions has always been important for safe navigation ‒ but mariners are not the only people who want to know about wrecks. They are also important for marine archeology, recreational diving, salvage operations, and fishing, among other interests. Now, Coast Survey has improved our Wrecks and Obstructions Database, giving everyone easy access to new records to explore.

Web-based map of wrecks
Coast Survey’s wrecks and obstructions database provides info on thousands of wrecks.

Historically, Coast Survey has maintained two separate sources of information on wrecks. We recently combined the sources, bringing together information on nearly 20,000 wrecks and obstructions.


Coast Survey established the Automated Wreck and Obstruction Information System (AWOIS) database in 1981 to help estimate the level of effort required to investigate items during a planned hydrographic survey, but maritime users were also interested in AWOIS’ historical records. However, because the emphasis is on features that are most likely to pose a hazard to navigation, AWOIS has always had limitations. Most notably, AWOIS is not a comprehensive record and does not completely address every known or reported wreck. Additionally, for a number of reasons, AWOIS positions do not always agree with a charted position for a similar feature.


Coast Survey compiles NOAA’s electronic navigational charts (NOAA ENC®) from sources on features that are navigationally significant. As the official chart data used in electronic chart and display information systems (ECDIS), ENCs are the authoritative source of information about known or reported wrecks and are much more comprehensive than AWOIS. However, the features in an ENC typically lack the historic information and context provided by AWOIS.


Correcting for some overlap between the two source databases, Coast Survey’s new wrecks and obstructions database now contains information on about 13,000 wreck features and 6,000 obstructions. Wreck features from each original database are stored in separate layers but can be displayed together. Users may also choose a background map from several options.

The new database also offers users additional data formats from which to choose. Historically, shipwreck data in AWOIS was available in Adobe PDF and as Microsoft Access Database (MDB) format. More recently, KML/KMZ files replaced PDF and MDB formats, making it easier for public users to view AWOIS data, by using freely available software such as Google Maps or Google Earth. Now, in addition to KML/KMZ and Microsoft Excel formats for general users, Coast Survey provides the data in ArcGIS REST services and OGC WMS services, for use in GIS software programs or web-based map mashup sites.

After ten years of NOAA ENCs, nearly 10 million (free) downloads per month!

It was only ten short years ago that NOAA began issuing electronic navigational charts (NOAA ENC®) as official products. As we look back, the promises of a product that emerged a decade ago continue to beckon, with even more uses and greater usage.

“We still make the traditional paper charts that mariners have depended on, but the world of navigation is changing, and Coast Survey is helping to lead that change,” explains Rear Admiral Gerd Glang, director of NOAA’s Office of Coast Survey. “Increasingly, mariners use – and soon will be required to use – electronic systems and displays to view and manage the safe navigation of their ships.”

The initial focus of Coast Survey’s ENC program, as the effort began in 1997, was to provide electronic chart coverage of the nation’s 40 major commercial port areas. Coast Survey first issued provisional ENCs in July 2001, and asked the public to evaluate the new product. Two years later, after a million downloads and with strong approbation from the maritime industry, Coast Survey removed the “provisional” designation. It wasn’t long before Coast Survey started extending the program to smaller scale coastal ENCs that connected the ports.

Within six months of “officialdom,” Coast Survey had produced 364 ENCs. Today, Coast Survey has 995 ENCs, with more in the pipeline.

A Lake Charles pilot uses an ENC as they navigate the 300-foot wide Calcaseiu Channel. Photo by Tim Osborn.
A Lake Charles pilot uses an ENC as he navigates the 300-foot wide Calcaseiu Channel. Under keel clearance can be (maybe) a foot for large deep-draft transits. Photo by Tim Osborn.

Usage continues to surge. As recently as five years ago, we were averaging about 900,000 downloads a month. Now we average more than 9 million downloads a month – all of them free to any user, anywhere in the world. Granted, it is so easy to download our entire suite of charts that many users simply hit “all” for downloads – while they walk away to get a cup of coffee – and, by the time they return to their computer, the ten or twenty charts they really wanted are easy to pick out from the suite. That ease of downloading adds to the usefulness of ENCs.

ENCs, which are produced from a vector database of features, support real-time navigation as well as collision and grounding avoidance.
ENCs, which are produced from a vector database of features, support real-time navigation as well as collision and grounding avoidance.

The U.S. Coast Survey, our predecessor agency, published our first paper nautical chart – the Map of New York Bay and Harbor and the Environs – in 1845. In 1990, we began producing raster charts for use in electronic navigation systems. Raster navigational charts are digital pictures of paper charts, with geo-referencing and other digital data added. ENCs are also digital, but they contain data rather than simple pictures. Creating an electronic chart from a database of objects and their attributes gives users the ability to turn the objects on and off when the chart is displayed on a computer screen.

ENCs can also alert mariners to danger. For instance, in March 2012, Coast Survey upgraded the ENCs that cover the approaches to the East Coast (US2EC04M, US2EC03M, US2EC02M, and US2GC12M), to alert mariners when they approach the right whale seasonal management areas, giving mariners better information to plan to reduce their speeds or avoid the areas altogether.

So much has changed in ten years. So much has improved. The next decade should bring ENC improvements that are equally exciting.