Your file, assateague_1997.zip is now ready. The file was compressed using the freeware utility Info-Zip. After downloading, it may be unzipped using the PKWARE pkunzip or Info-Zip unzip utilities. Info-Zip unzip may be downloaded from http://www.cdrom.com/pub/infozip/. The format you have selected is binary, with an ASCII text header file. The header file contains the georeferencing information, and is organized in the following fashion. (Description of data format taken from ArcView Spatial Analyst Help.) The binary raster file format is a simple format that can be used to transfer raster data between various applications. It consists of two files, the IEEE floating-point file and a supporting ASCII header file. The header file must have the same name as the data file, but with a .hdr file extension. The header data includes the following keywords and values: ncols - number of columns in the data set. nrows - number of rows in the data set. xllcenter or xllcorner - x-coordinate of the center or lower-left corner of the lower-left cell. yllcenter or yllcorner - y-coordinate of the center or lower-left corner of the lower-left cell. cellsize - cell size for the data set. nodata_value - value in the file assigned to cells whose value in unknown. This keyword and value is optional. The nodata_value defaults to -9999. byteorder - the byte order of the binary cell values. You can choose between two keywords, msbfirst or lsbfirst. Msbfirst is used for cell values written with the most significant bit first. Lsbfirst is used for cell values written with the least significant bit first. For example, ncols 480 nrows 450 xllcorner 378923 yllcorner 4072345 cellsize 30 nodata_value -32768 byteorder msbfirst The nodata_value for the LIDAR ATM data set is -9999. Your request generated a raster file with 1687 columns and 1381 rows. The resulting data file is 8.88727951049805 Mb in size. The following is a metadata record for the dataset you have extracted. Identification_Information: Citation: Citation_Information: Originator: Coastal Remote Sensing/Coastal Services Center Publication_Date: Jun 22,1999 Title: Aircraft Laser/GPS Mapping of Coastal Topography. Other_Citation_Details: This data set has been extracted from one much larger. See the URL for the location of this larger data set. Online_Linkage: http://www.csc.noaa.gov/crs/beachmap/index.html Description: Abstract: Laser beach mapping uses a pulsed laser ranging system mounted onboard an aircraft to measure ground elevation and coastal topography. The laser emits laser beams at high frequency and is directed downward at the earth's surface through a port 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 aircraft travels over the beach at approximately 60 meters per second while surveying from the low water line to the landward base of the sand dunes. Purpose: This data was collected as part of an effort to map beach topography efficiently and cheaply. Supplemental_Information: This data set was collected with a LIDAR (LIght Detection And Ranging) instrument designed and developed by the Observational Sciences Branch (OSB) of NASA at the Wallops Flight Facility in Virginia. The instrument, originally designed for mapping ice sheets in Greenland, is called the Airborne Topographic Mapper or ATM. The ATM II (the latest version), operates with a Spectra Physics laser transmitter, which provides a 7 nanoseconds long, 250 microjoules pulse at a frequency-doubled wavelength of 523 nanometers in the blue-green spectral region. The laser transmitter can function at pulse rates from 2 to 10 kilohertz (kHz). The laser system with a separate cooling unit weighs approximately 45 kilograms (kg) and requires approximately 15 amperes of power at 115 volts. The transmitted laser pulse is reflected to the earth's surface with the aid of a small folding mirror mounted on the back of a secondary mirror of a rotating scan mirror assembly mounted directly in front of the telescope. The scan mirror, which is rotated at 20 hertz, is comprised of a section of round aluminum stock, machined to a specific off-nadir angle. A scan mirror with the off-nadir angle of 15 degrees was utilized, producing an elliptical scan pattern with a swath width equal to 50 percent of the approximately 700-meter aircraft altitude. The reflected laser pulse is transmitted to a photo-multiplier assembly that consists of a lens, a narrow bandpass filter, and a single photomultiplier tube. Note: The Spatial Reference section of this document may lack fully FGDC-compliant information regarding projection parameters (i.e., Central meridian, false Northing, etc.). The State Plane or UTM Zone will be supplied, and the corresponding parameters can be found in Appendix C of: Snyder, John, 1987, Map Projections, a Working Manual (U.S. Geological Survey Professional Paper 1395): Washington, U.S. Government Printing Office. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: Sep 15, 1997 Ending_Date: Sep 15, 1997 Currentness_Reference: Sep 15, 1997 to Sep 15, 1997 Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -75.1380480968392 East_Bounding_Coordinate: -75.0416447111452 North_Bounding_Coordinate: 38.3550223230754 South_Bounding_Coordinate: 38.2927272605753 Keywords: Theme: Theme_Keyword_Thesaurus: GCMD Theme_Keyword: EARTH SCIENCE > LAND SURFACE > Topography > Terrain Elevation Theme_Keyword_Thesaurus: None Theme_Keyword: lidar Theme_Keyword: laser Theme_Keyword: beach Theme_Keyword: topography Theme_Keyword: digital elevation model Theme_Keyword: DEM Theme_Keyword: erosion Place: Place_Keyword_Thesaurus: None Place_Keyword: U.S. Coastline Access_Constraints: none Use_Constraints: This data was collected for the purposes of research. Any conclusions drawn from analysis of this information are not the responsibility of NOAA or the Coastal Services Center. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: Coastal Remote Sensing Program Contact_Position: BeachMap Project Scientist Contact_Address: Address_Type: mailing and physical address Address: 2234 South Hobson Avenue City: Charleston State_or_Province: South Carolina Postal_Code: 29405 Country: United States Contact_Voice_Telephone: (843) 740-1200 Contact_Electronic_Mail_Address: csc@csc.noaa.gov Data_Set_Credit: This data was collected by the Observational Sciences Branch at the NASA Wallops Flight Facility. Portions of the work were funded by the USGS Center for Coastal and Regional Marine Geology, and by the NOAA Coastal Services Center. Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Raster Raster_Object_Information: Raster_Object_Type: Grid cell Row_Count: 1381 Column_Count: 1687 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Grid_Coordinate_System: Grid_Coordinate_System_Name: Universal Transverse Mercator UTM_Zone_Number: 18 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: coordinate pair Coordinate_Representation: Abscissa_Resolution: 0.0872313772528185 Ordinate_Resolution: 0.11119104 Planar_Distance_Units: meters Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1983 Ellipsoid_Name: Geodetic Reference System 80 Semi-major_Axis: 6378137 Denominator_of_Flattening_Ratio: 298.257 Vertical_Coordinate_System_Definition: Altitude_System_Definition: Altitude_Datum_Name: North American Vertical Datum of 1988 Altitude_Resolution: 0.01 Altitude_Distance_Units: meters Altitude_Encoding_Method: Explicit elevation coordinate included with horizontal coordinates Metadata_Reference_Information: Metadata_Date: 19980331 Metadata_Review_Date: 19980331 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: NOAA Coastal Services Center Contact_Position: Metadata Specialist Contact_Address: Address_Type: mailing and physical address Address: 2234 South Hobson Avenue City: Charleston State_or_Province: SC Postal_Code: 29405-2413 Contact_Voice_Telephone: none Contact_Electronic_Mail_Address: metadata@csc.noaa.gov Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: 19950324