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Short Citation:
Office of Coast Survey, 2024: NOAA's Hydrographic Surveys and Reports,

Item Identification

Title: NOAA's Hydrographic Surveys and Reports
Short Name: hydro_parent
Status: In Work
Publication Date: 1834

The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data to support the compilation of nautical charts and for safe navigation and to provide basic data for engineering, scientific and other commercial and industrial activities. Hydrographic survey data consists primarily of water depths but also includes features (rocks, wrecks, etc.), navigational aids, shoreline and some bottom type information. Such data can also be used for storm surge modeling and fish habitat studies and support a variety of maritime functions such as port and harbor maintenance, coastal engineering, and coastal zone management.


The Hydrographic Surveys Division (HSD) coordinates the acquisition, processing and management of marine geographic data, primarily for nautical charting to support safe navigation. To meet its charting mandate, NOAA maintains a suite of approximately 1,000 nautical charts. More than 50% of the areas covered by these charts are based on lead line soundings acquired prior to 1940. Some remote areas have never been adequately surveyed.



Other Citation Details:

The data were created by NOAA/HSD. Publication Date Range is 1834 through present.

Supplemental Information:

The first hydrographic surveys conducted by NOAA's predecessor organization (Survey of the Coast) date from the 1830's when lead lines were used to determine depth. Depth measurement techniques improved with the introduction of single beam echo sounders (1920's), the development of a continuously recording capability (late 1930's) and the utilization of multibeam sonar systems and airborne LIDAR (mid to late 1990's). These latter two systems plus side scan sonar provided much more complete coverage of the seafloor, thus lessening the possibility of undetected hazards to navigation. As depth measurement methods were evolving, positioning techniques also improved from three-point sextant fixes, to land-based electronic positioning systems and finally to the currently used Global Positioning System (GPS). These various techniques have a variety of accuracies associated with them. Presently there are over 10,000 archived hydrographic surveys, of which approximately 6,000 are also in digital format. Note: Spatial reference information varies, please see survey reports for additional information.


Theme Keywords

Thesaurus Keyword
ISO 19115 Topic Category
ISO 19115 Topic Category
NOS Data Explorer Topic Category bathymetry/topography
None bathymetry
None charting
None coastline
None depth
None hydrographic data
None hydrography
None morphology
None navigation surveys
None ocean
None seafloor topography
None sonar
None soundings
None water depth

Spatial Keywords

Thesaurus Keyword
None coastal waters
None United States

Physical Location

Organization: Office of Coast Survey
City: Silver Spring
State/Province: MD

Data Set Information

Data Set Scope Code: Data Set
Maintenance Frequency: As Needed
Data Presentation Form: PDF file (reports), MrSID and TIFF (surveys)
Distribution Liability:

This data is not for navigational purposes. While every effort has been made to ensure that this data is accurate and reliable, NOAA assumes no liability for any damage caused by any errors or omissions in the data.

Support Roles

Data Steward

CC ID: 808924
Date Effective From: 2018-12-14
Date Effective To:
Contact (Person): Keown, Patrick
Address: 1315 East West Hwy
Silver Spring, MD 20910-3282
Email Address:
Phone: 240-533-0031


CC ID: 808925
Date Effective From: 2018-12-14
Date Effective To:
Contact (Organization): Office of Coast Survey (OCS)
Address: 1315 East West Highway
Silver Spring, MD 20910

Metadata Contact

CC ID: 808926
Date Effective From: 2018-12-14
Date Effective To:
Contact (Person): Keown, Patrick
Address: 1315 East West Hwy
Silver Spring, MD 20910-3282
Email Address:
Phone: 240-533-0031

Point of Contact

CC ID: 808927
Date Effective From: 2018-12-14
Date Effective To:
Contact (Person): Keown, Patrick
Address: 1315 East West Hwy
Silver Spring, MD 20910-3282
Email Address:
Phone: 240-533-0031


Currentness Reference: Publication Date

Extent Group 1

Extent Group 1 / Geographic Area 1

CC ID: 494486
W° Bound: -180
E° Bound: -64
N° Bound: 71
S° Bound: 15

Extent Group 1 / Time Frame 1

CC ID: 494485
Time Frame Type: Continuing
Start: 1834

Access Information

Security Class: Unclassified
Data Access Procedure:

Price information is available upon request. Pre-payment is possible by check, money order or bankcard. There is a standard handling charge with additional costs for special handling. Orders can be placed by fax, e-mail, regular mail or telephone. Data is available over internet using GEODAS and may be downloaded without charge. Ordering Instructions: Tide and water level data can be obtained through the National Ocean Service Center for Operational Oceanographic Products and Services. Tide and Tidal Current Predictions Contact: Stephen Lyles Phone: 301-713-2877 extension 176 Email: Great Lakes Benchmark and Leveling Contact: Jeff Oyler Phone: 757-436-0200 Email: National Ports Contact: Captain David McFarland Phone: 301-713-2981 extension 127 Email: David; Tide and water level data can be obtained through the National Ocean Service's Center for Operational Oceanographic Products and Services.Tide and Tidal Current Predictions:Contact: Stephen LylesPhone: 301-713-2877 extension 176Email: Stephen.Lyles@noaa.govGreat Lakes Benchmark and Leveling:Contact: Jeff OylerPhone: 757-436-0200Email: Jeff.Oyler@noaa.govNational Ports:Contact: Captain David McFarlandPhone: 301-713-2981 extension 127Email: David;

Data Access Constraints:


Data Use Constraints:

These data sets are not for navigational purposes. The data used by the National Oceanic and Atmospheric Administration (NOAA) have no warranty expressed or implied as to the accuracy. The act of distribution shall not constitute any such warranty, and no liability or responsibility is assumed by NOAA in the use of this data, software, or related materials.

Distribution Information

Distribution 1

CC ID: 494487
Download URL:
Distributor: Office of Coast Survey (OCS) (2018-12-14 - Present)

Downloadable data

File Type (Deprecated): PDF file for descriptive report.
Distribution Format: PDF - Adobe Portable Document Format

Distribution 2

CC ID: 494489
Download URL:
Distributor: Office of Coast Survey (OCS) (2018-12-14 - Present)

Downloadable data

File Type (Deprecated): Hybrid NGDC format created from vector survey file.

Distribution 3

CC ID: 494488
Download URL:
Distributor: Office of Coast Survey (OCS) (2018-12-14 - Present)

Downloadable data

File Type (Deprecated): Mr. SID and TIFF survey files.
Distribution Format: SID-MrSID/Multiresolution Seamless Image DB



CC ID: 494479
URL Type:
Online Resource

Main webpage.

Activity Log

Activity Log 1

CC ID: 494509
Activity Date/Time: 2010-09-29

Date that the source FGDC record was last modified.

Activity Log 2

CC ID: 494508
Activity Date/Time: 2017-04-05

Converted from FGDC Content Standards for Digital Geospatial Metadata (version FGDC-STD-001-1998) using '' script. Contact Tyler Christensen (NOS) for details.

Activity Log 3

CC ID: 718990
Activity Date/Time: 2018-02-08

Partial upload of Positional Accuracy fields only.

Data Quality

Horizontal Positional Accuracy:

A variety of methods, with a variety of accuracies, have been used over the years to position survey vessels and hence soundings. The earliest technique was the use of onboard sextants to measure the angles between three precisely located objects on shore, an adaptation of the land surveying technique known as resection. While this method could yield quite accurate results, if very stringent procedures were followed, it was limited in its applicability offshore to the line-of-sight of the onshore objects/signals. This technique continued to be used for large scale surveys (1:5000) until the 1970's with positional accuracies in the 5 to 10 meter range. This technique could be used to determine positions beyond the sight of land by locating buoys using this method and then measuring the angles between three buoys. Accuracy was lost using this method because of the added uncertainty in the buoy positions. Fortunately, this decreased accuracy applied to soundings that were further offshore in deeper water and hence, of less navigational significance. The precursor to modern electronic positioning techniques was a method called Radio-Acoustic-Ranging whereby a TNT bomb was dropped off the stern of the surveying vessel and the explosion was listened for at two or more fixed hydrophone locations. When the fixed hydrophones received the signal for the explosion, this activated a radio transmitter that would immediately transmit the reception of the signal back to the surveying vessel. The time difference between the explosion and the received radio transmissions could be used to determine the vessels position. This technique, which was developed in 1924, could position vessels over 200 miles offshore and was used until the early 1940's. Electronic positioning became increasingly popular with the advent of Shoran in the mid-1940's, EPI in the early 1950's and Raydist in the late 1950's. Careful monitoring of this equipment was necessary to prevent errors due to electronic interference. Positional accuracy of these systems were typically in the 10 to 20 meter range. Land-based electronic positioning systems improved technologically and some systems were capable of accuracies less than 10 meters. These were widely used until the mid-1990's when the use of the Global Positioning System (GPS) in differential mode (DGPS) became the standard for most inshore surveys. Typical accuracies for DGPS derived positions are +/- 5 meters.

Vertical Positional Accuracy:

Early lead line vertical accuracy was difficult to ascertain. The bow existing in each lead line was not constant. The line may not have been vertical when a measurement was made. There was no way to know what adjustments should be applied to each measured water depth. Early single beam fathometer vertical accuracy was given as a percentage of the water depth. This percentage was not constant and could vary with increasing water depth. Various other ship and equipment related corrections were also needed: i.e. instrument error corrections, depth of the sounding capture device below the water surface, vertical displacement of the sounding capture device relative to its position at rest, when a ship is underway, velocity of sound correctors adjusted for time and space and corrections for ship motion caused by waves and swells, the error in the vessel's heading, and the time delay from the moment the position is measured until the data is received by the data collection system. The post 1970 multi-beam sonar system vertical accuracy is maintained and operated from data acquisition to processing with greater specificity. For example, it detects shoals that measure 2 meters x 2 meters horizontally and 1 meter vertically in depths of 40 meters or less. For depths greater than 40 meters, the minimum size of detectable targets is 10 percent of the depth for horizontal dimensions and 5 percent of the depth for vertical dimensions. Depths are determined and recorded with a vertical resolution no coarser than 10 centimeters. After 1990, surveying Side Scan Sonar began to supplement single and multi-beam soundings by searching the region between regular sounding lines. The side scan sonar system is operated in such a manner that it detects an object on the sea floor that measures 1 m x 1 m x 1 m from shadow length measurements.

Completeness Report:

Many areas portrayed on nautical charts have never been adequately surveyed for modern shipping needs. More than 50% of the areas covered by these charts are based on lead line soundings acquired prior to 1940. Additionally, until the 1990's, the spacing between sounding lines may have been too wide to discover all features on the seafloor including wrecks and other obstructions. Modern surveys using multibeam and side scan sonar increase the chances of locating all such features but due to equipment and resource limitations, there can be no guarantee that all have been found in an area. In areas of critical navigational importance (entrances to ports, heavily traveled nearshore sea lanes, etc.) the most rigorous survey techniques are used, decreasing the chance of missing important seafloor features, but not eliminating that possibility.

Conceptual Consistency:

Historically, various editions of the Hydrographic Manual (published in 1931, 1942, 1960 and 1976) provided guidance for accuracy and resolution. Current standards are set forth in the NOS Hydrographic Surveys Specifications and Deliverables (April 2009). All measured depths have been corrected for water level relative to chart datum, dynamic vessel draft including settlement and squat, and sound velocity variations.


Process Steps

Process Step 1

CC ID: 494477

HSD has traditionally been the organization that acquired the bulk of the hydrographic survey data. Beginning in 1834 hydrographic data was collected by a fleet of survey ships in deep water operations supplemented inshore by field parties. Since the late 1990's many surveys have been by contractors. Through the years this process of data capture has been supplemented by other government agencies like the Corps of Engineers in channel dredging and the United States Coast Guard in Notice to Mariner publications warning of navigation dangers. Private citizens can also contribute data by sending correspondence depicting wrecks, obstructions or shoals.

Catalog Details

Catalog Item ID: 39979
GUID: gov.noaa.nmfs.inport:39979
Metadata Record Created By: Tyler Christensen
Metadata Record Created: 2017-04-05 13:49+0000
Metadata Record Last Modified By: SysAdmin InPortAdmin
Metadata Record Last Modified: 2023-10-17 16:12+0000
Metadata Record Published: 2018-12-14
Owner Org: OCS
Metadata Publication Status: Published Externally
Do Not Publish?: N
Metadata Last Review Date: 2018-12-14
Metadata Review Frequency: 1 Year
Metadata Next Review Date: 2019-12-14