NOAA’s Automated Distribution Infrastructure for Digital Charts
LCDR Mark Wetzler1, Marc Higgins1, John Tucker1and Brad Christian2
1NOAA’s Office of Coast Survey and 2Rose Point Navigation Systems
NOAA has developed a hardware and file infrastructure which allows third parties to build
software that can automate the downloading of the current versions of NOAA’s digital nautical
charts. The distribution infrastructure consists of three components: Three geographically
separated and mirrored Web servers with high bandwidth connections to the internet; static links
to NOAA chart files; and two eXtensible Markup Language (.XML) product catalogs—one for
Electronic Navigational Charts (ENCs) and one for Raster Navigational Charts (RNCs). The
product catalogs contain chart metadata, release dates and URL addresses of the static links for
downloading the charts.
Software applications can be developed that read the .XML product catalog files to determine the
current status of charts available. This can be compared to the status of charts on a mariner’s
system, and needed updates automatically determined for download to the mariner’s computer.
Electronic Chart System (ECS) and Electronic Chart Display and Information System (ECDIS)
developers can build applications which automate the management of user chart suites thus
enabling mariners to always have the current chart edition directly from NOAA. Today’s high
bandwidth Internet connections via satellite, WiFi access at marinas, and cell tower connections
allow for downloads to occur while at sea.
NOAA produces, maintains and makes available for free distribution a suite of 671 ENCs and
1019 RNCs. During an average week there are 225 critical corrections applied to 55 ENCs and
115 RNCs. This large volume of updates makes it difficult for the user to manually maintain a
local chart suite. A chart suite that is maintained in an automated fashion, with information
downloaded directly from the hydrographic office, allows the user to effortlessly have the most
*Note—Any mention of a commercial product is for informational purposes and does not constitute an
endorsement by the U.S. Government or any of its employees or contractors.
The foundation of the United States economy is the Marine Transportation System— the
network of oceans, rivers, canals, locks, dams, ports, and aids to navigation. Shipping on these
“marine highways” moves people and cargo around the country, and connects the US to global
markets for international trade and affordable goods. The importance of these highways is
significant. Roughly 15% of the United States Gross Domestic Product flows through the ports.
Water born commerce in the U.S. is a $1 trillion industry. More than 78% of U.S. overseas trade
by weight and 38% by value comes and goes by shipi. The Office of Coast Survey (OCS) is
responsible for producing the suite of nautical charts that covers the coastal waters of the U.S.
and its territories, in support of this vital waterborne commerce.
Other constituents who rely on the suite of nautical charts include the U.S. fisheries industry and
recreational boaters. In 2006 alone the fishing industry generated $103 billion in sales, $44.3
billion in income and supported over 1.5 million jobs.ii The U.S. Coast Guard reported that there
were 12,746,126 registered recreational boats in the U.S. in 2006.iii
OCS is working to be the provider of choice for information needed for safe navigation and to
expand its constituent base beyond the traditional navigation community.iv A methodology to
realize these goals is to enhance the product distribution system thereby making products more
readily available. This will result in increased breadth, speed, and frequency of chart
The automated distribution infrastructure described in this paper significantly enhances OCS’s
current distribution mechanism by allowing third party programmers to directly access chart
suite metadata and data. The end result is that the mariner will increase efficiency and improve
navigational safety by always having the most recent digital chart edition aboard with minimal
In 2002 OCS began delivering ENCs to customers digitally with a commercially available Web
based distribution package. The service was expanded in 2005 to include distribution of RNCs.
The commercial interface was designed to meet the needs of the majority of customers by
providing graphical and textual methods for selecting and downloading desired charts. The
software was designed for manual selection and download of charts by individual users. No
functionality for automated selection and download was available within the commercial
Several times a year OCS would receive requests from customers, Web developers, and ECS
programmers asking for chart metadata so that they could develop software or processes utilizing
that metadata. From a review of customer inquiries it was clear that software developers who
wanted to automate processes were not having their needs met with the commercial package and
its manual selection and download interface.
Simultaneously, OCS was also developing Continuity of Operations (COOP) plan. One aspect
was to resolve how to continue chart distribution if the server for distributing charts was
unavailable. By working with NOAA’s Web Operation Center (WOC) a simple COOP solution
was implemented. Once a week all of the ENCs and RNCs were packaged into two .ZIP files,
uploaded to the WOC and mirrored to three geographically separated servers that were publicly
available. Over time it was found that many customers preferred this distribution mechanism
over the existing Web based distribution package. This preference was due to its reliability,
bandwidth and simplicity. Based upon customer requests and strategic evolution the WOC site
(www.charts.noaa.gov) evolved, but the basic requirement of simplicity was kept.
During a February 2006 visit from industry NOAA was requested to make metadata available to
supplement product distribution. The recommendation was that metadata be placed in an .XML
format and made available online.
With customer requirements, robust Web distribution technology, and a metadata model to
emulate, OCS began generating .XML files containing chart metadata in January of 2008. The
project objective was to “Make up-to-date Nautical Chart System (NCS) data easily accessible to
developers for reliable redistribution of chart products and services.”v In addition to the two full
suite .ZIP files, the charts were prepackaged and made available as regional in individual .ZIP
files. This increased flexibility for developing systems that automate download.
Though the development of the infrastructure was not revolutionary, it is a strong example of
evolution of a business model based on customer feedback, analysis of Web statistics, and
appropriate use of Web technology.
OCS Business Model for Digital Chart Product Distribution
The new business model for chart product distribution is tiered based upon customer needs and
skill levels. The automated distribution infrastructure is designed for advanced customers, i.e.
developers and distributors. Table 1 portrays three tiers of OCS customers, by experience level,
with corresponding links to the distribution mechanism.
Digital Data Distribution Model
Defining Characteristics Mechanism to Access Products Current URL
Do not know what products are available. RNC Graphical User Interface (GUI) http://www.charts.noaa.gov/InteractiveCatalog/nrnc.shtml
Might be interested in viewing one or two charts or
downloading charts in a coverage area. Chart
numbers do not mean much to this group.
Geographic catalog is of the most value.
ENC Graphical User
Interface (GUI) http://www.charts.noaa.gov/InteractiveCatalog/nenc.shtml
Understand chart catalogs and chart numbers. Text Interface http://www.charts.noaa.gov/RNCs/RNCs.shtml
Want to download a set of charts for their local
area. Text Interface http://www.charts.noaa.gov/ENCs/ENCs.shtml
GUI by State http://www.charts.noaa.gov/InteractiveCatalog/nstate.shtml
GUI by Coast Guard District http://www.charts.noaa.gov/InteractiveCatalog/ncgd.shtml
Want to automate download by checking .XML
file. RNC Product Catalog http://www.charts.noaa.gov/RNCs/RNCProdCat.xml
Want to check to see most current product. ENC Product Catalog http://www.charts.noaa.gov/ENCs/ENCProdCat.xml
Want to develop a portfolio management system
for their customers.
Want to automate processing of chart information
Digital Data Distribution Model by Customer Skill Levels
By expanding service to meet the needs of the advanced user in the OCS distribution business
model, there are two positive outcomes: first, the end user has more options to access the data;
and second, the data provided is directly from NOAA servers and is therefore the most current
data available. The advanced users with direct access to the .XML files containing chart
metadata are able to design products and services to meet their customers’ needs by simplifying
the chart updating process. This is important because NOAA chart product information is
dynamic and changes daily for the ENCs and weekly for the RNCs.
The business model work flow for the advanced users is shown in Diagram 1 below.
Fundamentally, data is generated and packaged within OCS and uploaded to the