1-Arc Second National Elevation Dataset

Metadata:

• Identification_Information
• Data_Quality_Information
• Spatial_Data_Organization_Information
• Spatial_Reference_Information
• Entity_and_Attribute_Information
• Distribution_Information
• Metadata_Reference_Information

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.

QUADNAME	RESOLUTION	ULLAT	ULLON	LRLAT	LRLON	HDATUM	ZMIN	ZMAX	ZMEAN	ZSIGMA	PMETHOD	QUADDATE
empty	1	31.5	-112	31.25	-111.66666412	83	664	1579	880.49810791	77.95426941	5	20081001
ruby_AZ	10	31.5	-111.25055695	31.375	-111.12555695	27	1058.50402832	1955.90405273	1332.78747559	122.80542755	5	20030201
saucito_mountain_AZ	10	31.75	-111.25055695	31.625	-111.12555695	27	979.11199951	1590.81201172	1107.55737305	77.13238525	5	20030201
presumido_peak_AZ	10	31.625	-111.62555695	31.5	-111.50055695	27	995.79901123	1467.49902344	1125.9699707	62.98012924	5	20030201
arivaca_AZ	10	31.625	-111.37555695	31.5	-111.25055695	27	1072.92895508	1635.82897949	1182.9934082	62.12613297	5	20030201
murphy_peak_AZ	10	31.625	-111.25055695	31.5	-111.12555695	27	1090.77600098	1705.27600098	1256.43347168	104.15414429	5	20030201
south_komelik_AZ	10	31.75	-111.87555695	31.625	-111.75055695	27	694.92498779	927.32501221	745.42694092	27.14586449	5	20030201
empty	1	31.75	-112	31.5	-111.66666412	83	669	1309	815.79327393	83.06108093	5	20081001
cumero_mountain_AZ	10	31.5	-111.50055695	31.375	-111.37555695	27	1059.32995605	1455.72998047	1190.77478027	81.90775299	5	20030201
wilbur_canyon_AZ	10	31.625	-111.50055695	31.5	-111.37555695	27	1029.21899414	1462.11901855	1145.12683105	76.19487	5	20030201
san_miguel_AZ	10	31.625	-111.87555695	31.5	-111.75055695	27	741.4420166	1278.24194336	795.61279297	53.34951019	5	20030201
aguirre_peak_AZ	10	31.75	-111.75055695	31.625	-111.62555695	27	780.57696533	1616.97705078	997.05529785	192.22532654	5	20030201
las_guijas_AZ	10	31.75	-111.50055695	31.625	-111.37555695	27	957.87103271	1401.67102051	1042.08251953	49.14554977	5	20030201
cerro_colorado_AZ	10	31.75	-111.37555695	31.625	-111.25055695	27	973.90802002	1620.00805664	1122.84216309	83.54639435	5	20030201
	19	0	0	0	0	0	0	0	0	0	7	20090318
mildred_peak_AZ	10	31.75	-111.62555695	31.625	-111.50055695	27	1049.30700684	1765.60705566	1211.0847168	127.34393311	5	20030201
bartlett_mountain_AZ	10	31.5	-111.37555695	31.375	-111.25055695	27	1073.36096191	1551.66101074	1270.68334961	76.02485657	5	20030201
	19	0	0	0	0	0	0	0	0	0	7	20081229
caponera_peak_AZ	10	31.625	-111.75055695	31.5	-111.62555695	27	781.065979	1493.76599121	962.43225098	164.25933838	5	20030201
empty	1	31.5	-111.66666412	31.25	-111.33333588	83	839	1477	1036.84155273	102.5374527	5	20081001

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:-111.829999999185

East_Bounding_Coordinate:-111.249999999146

North_Bounding_Coordinate:31.6999999989157

South_Bounding_Coordinate:31.3999999988955

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: 1080

Column_Count: 2088

Vertical_Count: 1

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Geographic:

Latitude_Resolution: 0.00001

Longitude_Resolution: 0.00001

Geographic_Coordinate_Units: Decimal degrees

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

Vertical_Coordinate_System_Definition:

Altitude_System_Definition:

Altitude_Datum_Name: North American Vertical Datum of 1988

Altitude_Resolution: 1.000000

Altitude_Distance_Units: meters

Altitude_Encoding_Method: Implicit coordinate

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