Identification_Information: Citation: Citation_Information: Title: OFR_2007-1179 Geospatial_Data_Presentation_Form: remote-sensing image Description: Abstract: A bare earth elevation map (also known as a Digital Elevation Model or DEM) of George Washington Birthplace National Monument was produced from remotely-sensed, geographically-referenced elevation measurements in cooperation with the U.S. Geological Survey (USGS), the National Air and Space Administration (NASA), and the National Park Service (NPS). Elevation measurements were collected over the area using the NASA Experimental Advanced Airborne Research Lidar (EAARL), a pulsed laser ranging system mounted onboard an aircraft to measure ground elevation, vegetation canopy, and coastal topography. The system uses high frequency laser beams directed at the earth's surface through an opening in the bottom of the aircraft's fuselage. The laser system records the time difference between emission of the laser beam and the reception of the reflected laser signal in the aircraft. The plane travels over the target area at approximately 50 meters per second at an elevation of approximately 300 meters. The EAARL, developed by NASA at Wallops Flight Facility in Virginia, measures ground elevation with a vertical resolution of 15 centimeters. A sampling rate of 3 kHz or higher results in an extremely dense spatial elevation data set. Over 100 kilometers of coastline can be easily surveyed within a 3- to 4-hour mission time period. When subsequent elevation maps for an area are analyzed, they provide a useful tool to make management decisions regarding land development. Purpose: The purpose of this project was to produce a highly detailed and accurate bare earth DEM of George Washington Birthplace National Monument for use as a management tool and to make this map available to natural resource managers. Supplemental_Information: Raw Lidar data is not in a format that is generally usable by Park Service resource managers and scientists for scientific analysis. Converting dense Lidar elevation data into a readily usable format without loss of essential information requires specialized processing. The USGS converts raw Lidar data into a GIS-compatible map product to be provided to National Park Service GIS specialists, managers, and scientists. The primary tool used in the conversion process is Airborne Lidar Processing System (ALPS), a multi-tiered processing system developed by a USGS/NASA collaborative project. Specialized processing algorithms are used to convert raw waveform Lidar data acquired by the EAARL to georeferenced spot (x,y,z) returns for "first surface" and "bare earth" topography. These data are then converted to the North American Datum of 1983 and the North American Vertical Datum of 1988 (using the Geoid 03 model). Each file contains data located in a 2 km by 2 km tile where the upper left boundary can be quickly assessed through the file name. The first number in the filename (e####) is the left most UTM easting coordinate in thousands of meters, the second number (n####) is the top most UTM northing coordinate in thousands of meters, and the third number (##) is the UTM zone the tile is located within. Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: April 14, 2005 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Keywords: Theme: Theme_Keyword: Lidar Theme_Keyword: Experimental Advanced Airborne Research Lidar Theme_Keyword: EAARL Theme_Keyword: Digital Elevation Model Theme_Keyword: elevation change Theme_Keyword: laser altimetry Theme_Keyword: derived surface Theme_Keyword: resource management Theme_Keyword: bare earth elevation Theme_Keyword: ALPS Theme_Keyword: Airborne Lidar Processing System Place: Place_Keyword: George Washington Birthplace National Monument Place_Keyword: Virginia Access_Constraints: Any 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. See section 6.3 Distribution Liability. Use_Constraints: Although the USGS is making these data sets available to others who may find the data of value, USGS does not warrant, endorse, or recommend the use of this data for any given purpose. The user assumes the entire risk related to the use of these data. Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Dr. John C Brock Contact_Organization: United States Geological Survey, FISC St. Petersburg Contact_Position: Physical Oceanographer Contact_Address: Address_Type: mailing and physical address Address: 600 4th Street South City: Saint Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: 727 803-8747 ext3088 Contact_Facsimile_Telephone: 727 803-2031 Contact_Electronic_Mail_Address: jbrock@usgs.gov Hours_of_Service: Monday-Friday, 8-5, EST Data_Set_Credit: The USGS is providing these data "as is", and the USGS disclaims any and all warranties, whether expressed or implied, including (without limitation) any implied warranties of merchantability or fitness for a particular purpose. In no event will USGS be liable to you or to any third party for any direct, indirect, incidental, consequential, special, or exemplary damages or lost profits resulting from any use or misuse of these data. Acknowledgement of the U.S. Geological Survey FISC St. Petersburg as a data source would be appreciated in products developed from these data, and such acknowledgement as is standad for citation and legal practices for data source is expected by users of this data. Sharing new data layers developed directly from these data would also be appreciated by the USGS staff. Users should be aware that comparisons with other data sets for the same area from other time periods may be inaccurate due to inconsistencies resulting from changes in photo interpretation, mapping conventions, and digital processes over time. These data are not legal documents and are not to be used as such. Native_Data_Set_Environment: Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.1.0.780 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: The expected accuracy of the measured variables are as follows: attitude within 0.07 degree, 3-cm nominal ranging accuracy, and vertical elevation accuracy of +/-15 cm for the topographic surface. Quality checks are built into the data-processing software. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Raw elevation measurements have been determined to be within 1 meter horizontal accuracy. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: Elevations of the DEM are vertically consistent with the point elevation data, +/-15 cm. Lineage: Source_Information: Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 20050414 Source_Currentness_Reference: ground condition Process_Step: Process_Description: The data are collected using a Cessna 310 aircraft. The NASA Experimental Advanced Airborne Research Lidar (EAARL) laser scanner collects the data using a green (532nm) raster scanning laser, while a digital camera acquires a visual record of the flight. The data are stored on hard drives and archived at the USGS FISC office in St. Petersburg, FL and at the NASA office at Wallops Flight Facility. The navigational data are processed at Wallops Flight Facility. The navigational and raw data are then downloaded into the Airborne Lidar Processing System (ALPS). Data are converted from units of time to x,y,z points for elevation. The derived surface data can then be converted into raster data (geotiffs). Process_Date: June 2005 - February 2006 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Amar Nayegandhi Contact_Organization: United States Geological Survey FISC St. Petersburg Contact_Position: Computer Scientist Contact_Address: Address_Type: mailing and physical address Address: 600 Fourth Street South City: St. Petersburg State_or_Province: Florida Postal_Code: 33701 Country: USA Contact_Voice_Telephone: 727-803-8747 ext. 3026 Contact_Facsimile_Telephone: 727-803-2032 Process_Step: Process_Description: The raster dataset was opened in ERDAS IMAGINE for editing. An Area of Interest (AOI) polygon was drawn around regions of poor data quality. Poor data quality was determined visually by locating gaps in the data as well as artifacts of the Lidar processing. Pixels within the AOI polygons were given a raster value of -100 to correspond with other areas of No Data. Process_Date: November 2006 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: National Park Service South Florida/Caribbean Network Inventory and Monitoring Program Contact_Person: Judd Patterson Contact_Position: Research Assistant Contact_Address: Address_Type: mailing and physical address Address: 18001 Old Cutler Road, Suite 419 City: Miami State_or_Province: Florida Postal_Code: 33157 Country: USA Contact_Voice_Telephone: (305) 252-0347 Process_Step: Process_Description: Metadata imported. Source_Used_Citation_Abbreviation: THST\Lidar\bare_earth\e320_n4268\be_e320_n4268_18z_edit.tif.xml Spatial_Data_Organization_Information: Indirect_Spatial_Reference: Tiling Index Direct_Spatial_Reference_Method: Raster Raster_Object_Information: Raster_Object_Type: Pixel Row_Count: 2001 Column_Count: 2001 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: 18 Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.999600 Longitude_of_Central_Meridian: -75.000000 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: 1.000000 Ordinate_Resolution: 1.000000 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 Vertical_Coordinate_System_Definition: Altitude_System_Definition: Altitude_Datum_Name: North American Vertical Datum of 1988 Altitude_Resolution: 15 cm Altitude_Distance_Units: meters Altitude_Encoding_Method: Explicit elevation coordinate included with horizontal coordinates Entity_and_Attribute_Information: Overview_Description: Entity_and_Attribute_Detail_Citation: The variables measured by EAARL are: distance between aircraft and GPS satellites (m), attitude information (roll, pitch, heading in degrees), scan angle (degrees), second of the epoch (sec), and 1-ns time-resolved return intensity waveform (digital counts). Z value is referenced to orthometric elevations derived from National Geodetic Survey Geoid Model, Geoid03. Distribution_Information: Distributor: Contact_Information: Contact_Person_Primary: Contact_Person: Jerry Butcher Contact_Organization: United States Geological Survey FISC St. Petersburg Contact_Position: Windows System Administrator Contact_Address: Address_Type: mailing address Address: 600 4th Street South City: Saint Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: 727-803-8747 ext. 3049 Contact_Facsimile_Telephone: 727-803-2032 Contact_Electronic_Mail_Address: jbutcher@usgs.gov Resource_Description: Lidar DEM (George Washington Birthplace National Monument) Distribution_Liability: The United States Geological Survey shall not be held liable for improper or incorrect use of the data described and/or contained herein. These data and related graphics are not legal documents and are not intended to be used as such. The information contained in these data is dynamic and may change over time. The data are not better than the original sources from which they were derived. It is the responsibility of the data user to use the data appropriately and consistent within the limitations of geospatial data in general and these data in particular. The related graphics are intended to aid the data user in acquiring relevant data; it is not appropriate to use the related graphics as data. The United States Geological Survey gives no warranty, expressed or implied, as to the accuracy, reliability, or completeness of these data. It is strongly recommended that these data are directly acquired from an USGS server and not indirectly through other sources which may have changed the data in some way. Although these data have been processed successfully on a computer system at the United States Geological Survey, no warranty expressed or implied is made regarding the utility of the data on another system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. This disclaimer applies both to individual use of the data and aggregate use with other data. Standard_Order_Process: Non-digital_Form: Contact USGS for Details Digital_Form: Digital_Transfer_Information: Transfer_Size: 0.000 Custom_Order_Process: Call USGS for Details Metadata_Reference_Information: Metadata_Date: 20061208 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: United States Geological Survey FISC St. Petersburg Contact_Person: Jeremy Bracone Contact_Address: Address_Type: 600 4th Street South City: Saint Petersburg State_or_Province: FL Postal_Code: 33701 Contact_Voice_Telephone: (727)803-8747 Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Time_Convention: local time Metadata_Extensions: Online_Linkage: http://www.esri.com/metadata/esriprof80.html Profile_Name: ESRI Metadata Profile