Identification_Information: Citation: Citation_Information: Originator: U.S. Geological Survey (USGS) Publication_Date: 2011 Title: National Elevation Dataset (NED) Edition: 2 Geospatial_Data_Presentation_Form: raster digital data 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 paucity 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. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 19990201 Ending_Date: 20111101 Currentness_Reference: 20111101 Status: Progress: In work Maintenance_and_Update_Frequency: As needed Spatial_Domain: bounding_Coordinates: West_Bounding_Coordinate: -71.00055555556 East_Bounding_Coordinate: -69.99944444444 North_Bounding_Coordinate: 43.00055555556 South_Bounding_Coordinate: 41.99944444444 Keywords: Theme: Theme_Keyword_Thesaurus: National Elevation Dataset (NED) Theme_Keyword: NATIONAL ELEVATION DATASET Theme_Keyword: NED Theme_Keyword: ELEVATION Theme_Keyword: GRID Theme_Keyword: LIGHT DETECTION AND RANGING Theme_Keyword: LiDAR Theme_Keyword: LIDAR Theme_Keyword: HIGH RESOLUTION Theme_Keyword: EARTH SCIENCE Theme_Keyword: LAND SURFACE Theme_Keyword: TOPOGRAPHY Theme_Keyword: LANDFORMS Theme_Keyword: DRAINAGE AREA Theme_Keyword: HYDROLOGY Theme_Keyword: HYDROLOGIC Theme_Keyword: HYDROLOGIC MODELING Theme_Keyword: TERRAIN ELEVATION Theme_Keyword: 1-DEGREE DEM Theme_Keyword: 2-ARC-SECOND DEM Theme_Keyword: 7.5-MINUTE DEM Theme_Keyword: CARTOGRAPHY Theme_Keyword: DEM Theme_Keyword: DIGITAL ELEVATION MODEL Theme_Keyword: DIGITAL MAPPING Theme_Keyword: DIGITAL TERRAIN MODEL Theme_Keyword: EROS Theme_Keyword: GEODATA Theme_Keyword: GIS Theme_Keyword: MAPPING Theme_Keyword: RASTER Theme_Keyword: USGS Theme_Keyword: U.S. GEOLOGICAL SURVEY 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: NORTH AMERICA Place_Keyword: UNITED STATES Place_Keyword: UNITED STATES OF AMERICA Place_Keyword: US Access_Constraints: None. Any downloading and use of these data signifies a user's agreement to comprehension and compliance of the USGS Standard Disclaimer. Insure 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 this data set was collected and that some parts of this data may no longer represent actual surface conditions. Users should not use this 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 U.S. Geological Survey. Please refer to http://www.usgs.gov/privacy.html for the USGS disclaimer. Original statement: None. Acknowledgement of the originating agencies would be appreciated in products derived from these data. Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Raster Raster_Object_Information: Raster_Object_Type: Pixel Bits_Per_Pixel: 32 Row_Count: 10812 ColumnCount: 10812 Vertical_Count: 1 Spatial_Reference_Information: Horizontal_Cooordinate_System_Definition: Geographic: Latitude_Resolution: 0.00001 Longitude_Resolution: 0.00001 Geographic_Coordinate_Units: Decimal Degrees Planar: Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: Row and Column Coordinate_Representation: Abscissa_Resolution: 0.0000925925926 Ordinate_Resolution: 0.0000925925926 Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1983 Ellipsiod_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 Distribution_Information: Distributor: Contact_Information: Contact_Person_Primary: Contact_Person: Customer Service Representative Contact_Organization U.S. Geological Survey Contact_Address: Address_Type: mailing and physical address Address: USGS Earth Resources Observation & Science (EROS) Center 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_Facsimile_Telephone: 605-594-6589 Contact_Electronic_Mail_Address: webmapping@usgs.gov Hours_of_Service: 0800 - 1600 CT, M - F (-6h CST/-5h CDT GMT) Resource_Description: National Elevation Dataset (NED) Distribution_Liability: Although these data have been processed successfully on a computer system at the U.S. Geological Survey, Earth Resources Observation & Science (EROS) Center, no warranty, expressed or implied, is made by either regarding the utility of the data on any system, nor shall the act of distribution constitute any such warranty. The USGS will warranty the delivery of this product in computer-readable format and will offer appropriate adjustment of credit when the product is determined unreadable by correctly adjusted computer peripherals, or when the physical medium is delivered in damaged condition. Requests for adjustments of credit must be made within 90 days from the date of this shipment from the ordering site. Metadata_Reference_Information: Metadata_Date: 2009 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Customer Service Representative Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing and physical address Address: USGS Earth Resources Observation & Science (EROS) Center 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_Facsimile_Telephone: 605-594-6589 Contact_Electronic_Mail_Address: webmapping@usgs.gov Hours_of_Service: 0800 - 1600 CT, M - F (-6h CST/-5h CDT GMT) Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998