XYZ2008Data Series400Saint PetersburgU.S. Geological SurveyU.S. Geological SurveyUnknownfirstA bare earth elevation map (also known as a Digital Elevation Model, or DEM) of the northern Gulf of Mexico barrier islands and Naval Live Oaks was produced from remotely sensed, geographically referenced elevation measurements cooperatively by the U.S. Geological Survey (USGS), the National Park Service (NPS), and the National Aeronautics and Space Administration (NASA). 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 kilohertz or higher results in an extremely dense spatial elevation dataset. Over 100 kilometers of coastline can be surveyed easily within a 3- to 4-hour mission. When subsequent elevation maps for an area are analyzed, they provide managers with a useful tool to make management decisions regarding land development.The purpose of this project was to produce a highly detailed and accurate bare earth digital elevation map of the northern Gulf of Mexico barrier islands for use as a management tool and to make these data available to natural resource managers and research scientists.Unprocessed Lidar data are not in a format that is generally usable by resource managers and scientists. Converting dense Lidar elevation data into a readily usable format without loss of essential information requires specialized processing. The U.S. Geological Survey's Coastal and Marine Geology (CMG) Program has developed custom software to convert unprocessed Lidar data into a GIS-compatible map product to be provided to GIS specialists, managers, and scientists. The primary tool used in the conversion process is Advanced Lidar Processing System (ALPS), a multi-tiered processing system developed by a USGS-NASA collaborative project. Specialized processing algorithms are used to convert unprocessed waveform Lidar data acquired by the EAARL to georeferenced spot (x,y,z) returns for "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). The files are in the Quarter-Quad tiling format and are named after the U.S. Geological Survey Alpha Quarter-Quad naming convention ('QQ_naming_convention.doc'). The development of custom software for creating these data products has been supported by the U.S. Geological Survey CMG Program's Decision Support for Coastal Parks, Sanctuaries, and Preserves project. Processed data products are used by the U.S. Geological Survey CMG Program's National Assessments of Coastal Change Hazards project to quantify the vulnerability of shorelines to coastal change hazards such as severe storms, sea-level rise, and shoreline erosion and retreat.en2007062720070630ground conditionCompleteNone planned421832.119252527415765.7414607963346811.742395913339841.04619841421832.119252527415765.7414607963339841.046198413346811.74239591LidarExperimental Advanced Airborne Research LidarEAARLDigital Elevation Modelelevation changelaser altimetryderived surfaceresource managementALPSAdvanced Lidar Processing SystemHurricaneshttp://remotesensing.usgs.gov/FloridaMississippiAlabamahttp://nationalmap.gov/Gulf of MexicoCat IslandPetit Bois IslandDauphin IslandChandeleur IslandsHorn IslandShip IslandSanta Rosa IslandPerdido KeyNaval Live OaksBare earthhttp://lidar.cr.usgs.gov/2007http://www.esri.com/news/arcuser/1104/temporal.htmlAlthough the U.S. Geological Survey is making these datasets available to others who may find the data of value, the The U.S. Geological Survey, National Park Service, and National Aeronautical and Space Administration request the be acknowledged as originators of this data in future products or derivative research.Jacobs Technology, contracted to USGSAmar Nayegandhi or John Brock at USGSComputer Scientistmailing and physical address

600 4th Street South

Saint PetersburgFL33701USA727-803-8747 x3026anayegandhi@usgs.govM-F 8:30-5:00 ESTjbrock@usgs.govAcknowledgement of the U.S. Geological Survey, Florida Integrated Science Center, as a data source would be appreciated in products developed from these data, and such acknowledgement as is standard 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 U.S. Geological Survey staff. Users should be aware that comparisons with other datasets for the same area from other time periods may be inaccurate due to inconsistencies resulting from changes in photointerpretation, mapping conventions, and digital processes over time. These data are not legal documents and are not to be used as such.Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcMap 9.2.2.1350In PressInternational Journal of Remote SensingNayegandhi, A., Brock, J.C., Wright, C.WTaylor and FrancisLondon200218(1), p. 1-13Journal of Coastal Research18(1), p. 1-13Brock, J.C., Wright, C.W., Sallenger, A.H., Krabill, W.B., and Swift, R.N.Coastal Research and Education Foundation, Inc.Sallenger, A.H., Wright, C.W., and Lillycrop, J.200573(2-3), p. 10-14Shore and Beach73(2-3), p. 10-14XYZUnclassifiedunclassifiednoneThe expected accuracy of the measured variables are as follows: attitude within 0.07 degree, 3 cm nominal laser ranging accuracy, and vertical elevation accuracy of +/-15 cm for the topographic surface. Quality checks are built into the data-processing software.Unprocessed elevation measurements have been determined to be within 1 meter horizontal accuracy.Elevations of the DEM are vertically consistent with the point elevation data, +/-15 cm.2007062720070630ground conditionU.S. Geoloigcal Survey2008Data Series400FISC St. PetersburgU.S. Geological Surveyremote-sensing imageUnknownfirstPoint elevation measurements collected by the EAARL sensor.1noneunknownThe data are collected using a Cessna 310 aircraft. The NASA Experimental Advanced Airborne Research Lidar (EAARL) laser scanner collects the data using a green (532 nm) 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 U.S. Geological Survey office in St. Petersburg and the NASA office at Wallops Flight Facility. The navigational data are processed at Wallops Flight Facility. The navigational and unprocessed data are then downloaded into the Advanced 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).20070627 - 20080805mailing and physical address

600 4th Street South

Saint PetersburgFL33703USA727-803-8747 x3026M-F, 8:00-5:00 ESTanayegandhi@usgs.govJacobs Technology, U. S. Geological Survey, FISC St. PetersburgAmar NayegandhiComputer ScientistSeveral regions of the dataset are labeled as "No Data", which corresponds to a cell value of -32767 m in the XYZ file. These "No Data" areas are a result of the survey not covering a particular region, optical water depth of greater than 1.5 Secchi disc depths, or the manual removal of lidar processing artifacts.Each file contains data located in USGS 24K Quarter Quadrangle tile and are named after the USGS Alpha Quarter Quad naming convention. AAOOOaoq, where AA is the positive whole number component of the latitude. OOO is the positive whole number component of the longitude (zero-padded to a width of 3); a is an alpha character a-h designating which quad in the degree of latitude; where a is closest to 0 minutes and h is closest to the next full degree. Each represents 1/8 of a degree; o is a numeral 1-8 designating which quad in the degree of longitude, where 1 is closest to 0 minutes and 8 is closest to the next full degree. Each represents 1/8 of a degree; q is an alpha character a-d designating which quarter in the quad, where a is SE, b is NE, c is NW, and d is SW. Each quarter-quad is 1/16 of a degree in latitude and 1/16 of a degree in longitude.Pointrow and column2.0000002.000000metersUniversal Transverse Mercator160.999600-87.0000000.000000500000.0000000.000000North American Datum of 1983Geodetic Reference System 806378137.000000298.257222GCS_North_American_1983NAD_1983_UTM_Zone_16NNorth American Vertical Datum of 19880.15 mmetersExplicit elevation coordinate included with horizontal coordinatesThe 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.This raster represents Lidar-derived elevations.The XYZ ascii data is encoded with a 1-meter resolution.Project Managermailing address

600 4th Street South

Saint PetersburgFL33701USA727 803-8747M-F 8:30-5:00 ESTU.S. Geological SurveyProject ManagerDS 400This DVD publication was prepared by an agency of the United States Government. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, nor shall the act of distribution imply any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and (or) contained herein. Reference herin to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.varycontact U.S. Geological SurveyvaryXYZXYZ1.1DVDDVDContact U.S. Geological Survey for Details200820080307U. S. Geological SurveyMetadata Specialistmailing address

600 4th Street South

Saint PetersburgFL33701USA727-803-8747Metadata SpecialistFGDC Content Standards for Digital Geospatial MetadataFGDC-STD-001-1998local timeenhttp://www.esri.com/metadata/esriprof80.htmlESRI Metadata Profile20081010103047002008081412053800FALSE2008043013465800{953F59E8-286A-4413-BD08-14FEA20763D7}20081010Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.2.2.135030087b7c.xyz421832.119252527415765.7414607963346811.742395913339841.046198411-87.875-87.812530.2530.18751ISO 19115 Geographic Information - MetadataDIS_ESRI1.0dataset0.000Raster DatasetNAD_1983_UTM_Zone_16211732Meter1 Meter = 1 Meter(s)1062Meter1 Meter = 1 Meter(s)