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Feature Article

Improving Access to NOAA's Hydrographic Survey Metadata
Office of Coast Survey Continues to Add and Verify Survey Data to National Ocean Service Database

By Daniel Neumann
Senior IT Specialist
Office of Coast Survey
Silver Spring, Maryland

The Office of Coast Survey has provided more than two centuries of service to the marine transportation system, as America's source of navigational charts and data. The accuracy and precision of the data, used to create more than a thousand charts, makes the foundational hydrographic information a valuable resource for uses extending far beyond chart-making.

Although the public has historically been able to order copies of smooth sheets (plots of corrected water depth, showing relevant shoreline, hazards to navigation, channels and landmarks), old cumbersome procedures deterred full usage of the information. Since 2004, NOAA's National Geophysical Data Center (NGDC) has provided public access to digital Office of Coast Survey hydrographic survey products through its website. Instead of having users fill out forms or wait to receive an order, these online resources allow them to select a particular survey and product, and begin downloading the information immediately.

Search parameter entry.

The collection of these products, the National Ocean Service Hydrographic Survey Database, includes scanned survey reports and smooth sheets, and selected imagery, such as ship images and project sketches. The collection also includes bottom sample data and, for recent surveys, digital copies of survey reports and digital sounding data.

A subset of the survey database, the Hydrographic Survey Meta Database, which was added to the NGDC website in 2004, is especially appropriate when searching for particular information within NOAA's inventory of 16,400 hydrographic surveys. In 2010, NOAA added to this database Federal Geographic Data Committee (FGDC) and 'rap sheet' metadata, enabling users to immediately find information on a survey's instrumentation, navigation controls and other historical statistics.

Searching the Database and 'Rap Sheets'
Hydrographic survey metadata is housed in a relational database consisting of 35 Oracle tables. The tables satisfy the principal metadata needs for identifying and searching the characteristics of each hydrographic survey, including survey instrumentation, navigation, tide and sound speed correctors, and positioning.

All users need to do is enter known information into the search function, and the results appear in a table format. Users can select a particular survey for further investigation, or they can modify the search criteria. As in any search, more input provides shorter and more relevant lists. For instance, suppose a user wants high-resolution multibeam sonar data for an area in the middle of Chesapeake Bay. The user knows it was acquired during a 2008 survey, but that is all he or she knows.

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Daniel Neumann has worked with NOAA's Office of Coast Survey since 1974. He is senior information technology specialist in the Data Acquisition and Control Branch of the Hydrographic Surveys Division. With Lt. Cmdr. Gregg Glover, he created the Hydrographic Survey Meta Database in 2004. In 2010, he completed development of the rap sheet addition to the hydrographic survey product list.

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