Metadata:


Identification_Information:
Citation:
Citation_Information:
Originator: U.S. Geological Survey (USGS)
Publication_Date: 2009
Publication_Time: As Updated.
Title:
1-Arc Second National Elevation Dataset
Geospatial_Data_Presentation_Form: SDE raster digital data
Series_Information:
Series_Name: National Elevation Data (NED)
Issue_Identification: 0.1
Publication_Information:
Publication_Place: Sioux Falls, SD
Publisher: U.S. Geological Survey
Online_Linkage: <http://nationalmap.gov>
Online_Linkage: <http://seamless.usgs.gov>
Description:
Abstract:
The National Elevation Dataset (NED) is the primary elevation data product produced and distributed by the USGS. The NED provides the best available public domain raster elevation data of the conterminous United States, Alaska, Hawaii, and territorial islands in a seamless format. The NED is derived from diverse source data, processed to a common coordinate system and unit of vertical measure. All NED data are distributed in geographic coordinates in units of decimal degrees, and in conformance with the North American Datum of 1983 (NAD 83). All elevation values are provided in units of meters, and are referenced to the North American Vertical Datum of 1988 (NAVD 88) over the conterminous United States. The vertical reference will vary in other areas. NED data are available nationally at resolutions of 1 arc-second (approx. 30 meters) and 1/3 arc-second (approx. 10 meters), and in limited areas at 1/9 arc-second (approx. 3 meters). At present, the bulk of Alaska is only available at a 2 arc-second (approx. 60 meters) resolution, owing to a lack of higher resolution source data, though some areas are available at resolutions of 1 and 1/3 arc-second with plans for significant upgrades of the state over the next five years. The NED is updated on a nominal two month cycle to integrate newly available, improved elevation source data.
Purpose:
The NED serves as the elevation layer of The National Map, and provides basic elevation information for earth science studies and mapping applications in the United States. The data are utilized by the scientific and resource management communities for global change research, hydrologic modeling, resource monitoring, mapping and visualization applications.
Supplemental_Information:
The data obtained through The National Map Seamless Server is considered to be the "best available" data from the USGS. The range of dates for the NED 1-arc second data cover the inception date of the dataset to the date of the most recent update.
Historical data and other data may be obtained by contacting Customer Service, Earth Resources Observation & Science (EROS) Center at 1-800-252-4547. Spatial-specific information not available
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 19990201
Ending_Date: 20090201
Currentness_Reference: ground condition
Status:
Progress: In work
Maintenance_and_Update_Frequency: Quarterly
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -111.155986
East_Bounding_Coordinate: -109.824165
North_Bounding_Coordinate: 45.108945
South_Bounding_Coordinate: 44.132447
Keywords:
Theme:
Theme_Keyword_Thesaurus: National Elevation Dataset
Theme_Keyword: NED
Theme_Keyword: National Elevation Dataset
Theme_Keyword: elevation
Theme_Keyword: grid
Theme_Keyword: LiDAR
Theme_Keyword: Lidar
Theme_Keyword: LIDAR
Theme_Keyword: Light Detection And Ranging
Theme_Keyword: high-resolution
Theme_Keyword: topography
Theme_Keyword: USGS
Theme_Keyword: U.S. Geological Survey
Theme_Keyword: DEM
Theme_Keyword: Digital elevation model
Theme_Keyword: Elevation
Theme_Keyword: Digital terrain model
Theme_Keyword: Surface Model
Theme_Keyword: Hydrologic
Theme_Keyword: Hydrologic Modeling
Theme_Keyword: Drainage Area
Theme_Keyword: Hydrology
Theme:
Theme_Keyword_Thesaurus:
American Society of Photogrammetry and Remote Sensing
Theme_Keyword: National Standards for Spatial Digital Accuracy (NSSDA)
Theme:
Theme_Keyword_Thesaurus: ISO 19115 Category
Theme_Keyword: imageryBaseMapsEarthCover
Theme_Keyword: 010
Theme_Keyword: geoscientificInformation
Theme_Keyword: 008
Theme_Keyword: location
Theme_Keyword: 013
Place:
Place_Keyword_Thesaurus:
U.S. Department of Commerce, 1995, Countries, dependencies, areas of special sovereignty, and their principal administrative divisions, Federal Information Processing Standard 10-4,): Washington, D.C., National Institute of Standards and Technology
Place_Keyword: United States
Place_Keyword: U.S.
Place_Keyword: US
Place_Keyword: USA
Place:
Place_Keyword_Thesaurus:
U.S. Department of Commerce, 1987, Codes for the identification of the States, the District of Columbia and the outlying areas of the United States, and associated areas (Federal Information Processing Standard 5-2): Washington, D.C., National Institute of Standards and Technology
Place_Keyword: AK
Place_Keyword: HI
Place_Keyword: AS
Place_Keyword: GU
Place_Keyword: MH
Place_Keyword: FSM (Federated States of Micronesia)
Place_Keyword: MP
Place_Keyword: PW
Place_Keyword: PR
Place_Keyword: CAN
Place_Keyword: MX
Place:
Place_Keyword_Thesaurus: Geographic Names Information System
Place_Keyword: Alaska
Place_Keyword: Hawaii
Place_Keyword: American Samoa
Place_Keyword: Guam
Place_Keyword: Marshall Islands
Place_Keyword: Micronesia
Place_Keyword: Northern Mariana Islands
Place_Keyword: Palau
Place_Keyword: Puerto Rico
Place_Keyword: Canada
Place_Keyword: Mexico
Access_Constraints:
Any acquisition or use of these data signifies a user's agreement to comprehension and compliance of the USGS Standard Disclaimer. Ensure all portions of metadata are read and clearly understood before using these data in order to protect both user and USGS interests.
Use_Constraints:
There is no guarantee or warranty concerning the accuracy of the data. Users should be aware that temporal changes may have occurred since these data were collected and that some parts of these data may no longer represent actual surface conditions. Users should not use these data for critical applications without a full awareness of its limitations. Acknowledgement of the originating agencies would be appreciated in products derived from these data. Any user who modifies the data is obligated to describe the types of modifications they perform. User specifically agrees not to misrepresent the data, nor to imply that changes made were approved or endorsed by the USGS. Please refer to <http://www.usgs.gov/privacy.html> for the USGS disclaimer.
Point_of_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Position: Customer Service Representative
Contact_Address:
Address_Type: mailing and physical address
Address: USGS Earth Resources Observation & Science (EROS) Center
Address: 47914 252nd Street
City: Sioux Falls
State_or_Province: SD
Postal_Code: 57198-0001
Country: USA
Contact_Voice_Telephone: 605-594-6151
Contact_Voice_Telephone: 1-800-252-4547
Contact_TDD/TTY_Telephone: 605-594-6933
Contact_Facsimile_Telephone: 605-594-6589
Contact_Electronic_Mail_Address: custserv@usgs.gov
Hours_of_Service: 0800 - 1600 CT, M - F (-6h CST/-5h CDT GMT)
Security_Information:
Security_Classification_System: None
Security_Classification: Unclassified
Security_Handling_Description: None
Native_Data_Set_Environment:
Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 3; ESRI ArcCatalog 9.1.0.780

Data_Quality_Information:
Logical_Consistency_Report: N/A
Completeness_Report: N/A
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report: N/A
Vertical_Positional_Accuracy:
Vertical_Positional_Accuracy_Report: N/A
Lineage:
Process_Step:
Process_Description:
NED assembly and updating are accomplished with a highly automated production process that was developed specifically for this seamless elevation data set. The selection of source data is accomplished by an automated query of a database of USGS and partner-supplied DEMs. The "best available" data criteria are applied to select specific file-based DEMs from the database. The headers of the selected DEMs are read to create an index, which controls production and triggers subsequent processing steps. Industry standard tools from the National Geodetic Survey, NADCON and VERTCON, are used to perform horizontal and vertical datum transformations, respectively.
The source DEMs are projected from their native coordinate system to a geographic coordinate system (decimal degrees of latitude and longitude) using standard cartographic transformation software. Resampling of the original elevation values is done with an implementation of cubic convolution that is optimized for elevation data by maintaining the integrity of shorelines and water bodies. Artifact removal is performed on the older USGS Level 1 DEMs that were produced with photogrammetric methods. The "mean profile filter" was specifically designed to process these 7.5-minute DEMs. The filter process uses a series of directional filters to isolate the high-frequency artifacts, which are then subtracted from the DEM. The magnitude of these artifacts is small, typically less than 1 meter, so the change to the DEM is negligible, but the removal results in significant improvements in derivative elevation products, such as shaded relief, slope, and aspect
The final steps in the production process include paneling the DEMs to fill the 1- by 1-degree tile, filling slivers of missing data along DEM boundaries as necessary by interpolating adjacent values, and edge matching the seams along the DEM boundaries and tile edges. The edge match algorithm uses a feathering approach that maintains local slope continuity across the seam. Finally, a shaded-relief image of the tile is generated for inspection by an analyst to verify successful processing, especially artifact filtering and edge matching. In some cases, DEM header information, which automatically triggers certain processing options, is incorrect, and the result is data that are not acceptable for inclusion into the NED. These cases are detected in the visual inspection step, the DEM header is corrected, and the tile is submitted for reprocessing. Tiles passing inspection are transferred to the next release version, and the spatially referenced metadata are updated accordingly.
The metadata were created for display through The National Map Seamless Server at <http://seamless.usgs.gov>, and are available in several formats: HTML, TEXT, XML, FAQ and SGML.
Process_Date: Ongoing
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Position: Customer Service Representative
Contact_Address:
Address_Type: mailing and physical address
Address: USGS Earth Resources Observation & Science (EROS) Center
Address: 47914 252nd Street
City: Sioux Falls
State_or_Province: SD
Postal_Code: 57198-0001
Country: USA
Contact_Voice_Telephone: 605-594-6151
Contact_Voice_Telephone: 1-800-252-4547
Contact_TDD/TTY_Telephone: 605-594-6933
Contact_Facsimile_Telephone: 605-594-6589
Contact_Electronic_Mail_Address: custserv@usgs.gov
Hours_of_Service: 0800 - 1600 CT, M - F (-6h CST/-5h CDT GMT)

Spatial_Data_Organization_Information:
Direct_Spatial_Reference_Method: Raster
Raster_Object_Information:
Raster_Object_Type: Pixel
Row_Count: 88848
Column_Count: 286892
Vertical_Count: 1

Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Planar:
Grid_Coordinate_System:
Grid_Coordinate_System_Name: Universal Transverse Mercator
Universal_Transverse_Mercator:
UTM_Zone_Number: 12
Transverse_Mercator:
Scale_Factor_at_Central_Meridian: 0.999600
Longitude_of_Central_Meridian: -111.000000
Latitude_of_Projection_Origin: 0.000000
False_Easting: 500000.000000
False_Northing: 0.000000
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method: row and column
Coordinate_Representation:
Abscissa_Resolution: 8.629159
Ordinate_Resolution: 8.629159
Planar_Distance_Units: meters
Geodetic_Model:
Horizontal_Datum_Name: North American Datum of 1983
Ellipsoid_Name: Geodetic Reference System 80
Semi-major_Axis: 6378137.000000
Denominator_of_Flattening_Ratio: 298.257222

Entity_and_Attribute_Information:
Overview_Description:
Entity_and_Attribute_Detail_Citation:
A link to the NED Data Dictionary describing information that is included in the spatial metadata shapefiles acquired with the DEM is provided at the end of the Metadata Section of this document.

Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Position: Customer Service Representative
Contact_Address:
Address_Type: mailing and physical address
Address: USGS Earth Resources Observation & Science (EROS) Center
Address: 47914 252nd Street
City: Sioux Falls
State_or_Province: SD
Postal_Code: 57198-0001
Country: USA
Contact_Voice_Telephone: 605-594-6151
Contact_Voice_Telephone: 1-800-252-4547
Contact_TDD/TTY_Telephone: 605-594-6933
Contact_Facsimile_Telephone: 605-594-6589
Contact_Electronic_Mail_Address: custserv@usgs.gov
Hours_of_Service: 0800 - 1600 CT, M - F (-6h CST/-5h CDT GMT)
Resource_Description: Downloadable Data
Distribution_Liability:
Although these data have been processed successfully on a computer system at the USGS, no warranty expressed or implied is made by the USGS regarding the use of the data on any other system, nor does the act of distribution constitute any such warranty. Data may have been compiled from various outside sources. Spatial information may not meet National Map Accuracy Standards. This information may be updated without notification. The USGS shall not be liable for any activity involving these data, installation, fitness of the data for a particular purpose, its use, or analyses results.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: ARCG
Format_Version_Number: ArcGIS 9.3
Format_Specification: Raster
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name: <http://nationalmap.gov>
Network_Resource_Name: <http://seamless.usgs.gov>
Access_Instructions:
The URL, <http://seamless.usgs.gov>, provides a map interface that allows for data downloads within a customer defined area of interest. Zoom tools are available that can be used to investigate areas of interest on the map interface. The download tool allows the customer to capture layers from the map, utilizing The National Map Seamless Server process for downloading. A request summary page is then generated with the download layers listed. By clicking the "download" button on the summary page, a zipped file will be generated that can be saved on the customer's computer. The file can then be unzipped and imported into various user software applications.
Online_Computer_and_Operating_System: Not available for dissemination
Fees: None
Ordering_Instructions: None. Downloadable data.
Turnaround: Variable
Custom_Order_Process: None
Technical_Prerequisites:
At minimum, ESRI ArcGIS 9.1 Suite or equivalent GIS processing software and supporting operating systems.
Available_Time_Period:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 2009

Metadata_Reference_Information:
Metadata_Date: 20090323
Metadata_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Position: Customer Service Representative
Contact_Address:
Address_Type: mailing and physical address
Address: USGS Earth Resources Observation & Science (EROS) Center
Address: 47914 252nd Street
City: Sioux Falls
State_or_Province: SD
Postal_Code: 57198-0001
Country: USA
Contact_Voice_Telephone: 605-594-6151
Contact_Voice_Telephone: 1-800-252-4547
Contact_TDD/TTY_Telephone: 605-594-6933
Contact_Facsimile_Telephone: 605-594-6589
Contact_Electronic_Mail_Address: custserv@usgs.gov
Hours_of_Service: 0800 - 1600 CT, M - F (-6h CST/-5h CDT GMT)
Contact_Instructions:
The above is the contact information for the USGS Earth Resources Observation & Science (EROS) Center in Sioux Falls, SD. This is the digital data storage and distribution center for the USGS.
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998
Metadata_Time_Convention: local time
Metadata_Access_Constraints: None
Metadata_Use_Constraints: None
Metadata_Security_Information:
Metadata_Security_Classification_System: None
Metadata_Security_Classification: Unclassified
Metadata_Security_Handling_Description: None
Metadata_Extensions:
Online_Linkage: <http://www.esri.com/metadata/esriprof80.html>
Profile_Name: ESRI Metadata Profile
Metadata_Extensions:
Online_Linkage: <http://ned.usgs.gov/NED/metadata.asp>
Profile_Name: National Elevation Dataset (NED) Metadata