remote-sensing image
U.S. Geological Survey2011EAARL Coastal Topography-Cape Canaveral, Florida, 2009: First SurfaceData Series585St. Petersburg, FLU.S. Geological Survey
ASCII xyz point cloud data were produced from remotely sensed, geographically referenced elevation measurements cooperatively by the U.S. Geological Survey (USGS) and National Aeronautics and Space Administration (NASA), Kennedy Space Center, FL. 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, resulting in a laser swath of approximately 240 meters with an average point spacing of 2-3 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 easily surveyed within a 3- to 4-hour mission. When resultant elevation maps for an area are analyzed, they provide a useful tool to make management decisions regarding land development.
The purpose of this project was to produce highly detailed and accurate digital elevation maps of a portion of the Eastern Florida coastline for use as a management tool and to make these data available to natural-resource managers and research scientists.
Raw lidar data are not in a format that is generally usable by 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 U.S. Geological Survey's Coastal and Marine Geology Program (CMGP) has developed custom software to convert raw 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 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. The terms first surface and bare earth refer to the digital elevation data of the terrain, but while first-surface data includes vegetation, buildings, and other man-made structures, bare-earth data does not. The zero crossing of the second derivative (that is, detection of local maxima) is used to detect the first return, resulting in "first surface" topography, while the trailing edge algorithm (that is, the algorithm searches for the location prior to the last return where direction changes along the trailing edge) is used to detect the range to the last return or "bare earth" (the first and last returns being the first and last significant measurable portion of the return pulse). Statistical filtering, known as the Random Consensus Filter (RCF), is used to remove false bottom returns and other outliers from the EAARL topography data. The filter uses a grid of non-overlapping square cells (buffer) of user-defined size overlaid onto the original point cloud. The user also defines the vertical tolerance (vertical width) based on the topographic complexity and point sampling density of the data. The maximum allowable elevation range within a cell is established by this vertical tolerance. An iterative process searches for the maximum concentration of points within the vertical tolerance, and removes those points outside of the tolerance (Nayegandhi and others, 2009). These data are then converted to the North American Datum of 1983 and the North American Vertical Datum of 1988 (using the GEOID09 model). Each file contains data located in a 10-kilometer by 10-kilometer tile, where the upper-left bound can be assessed quickly through the filename. The first 3 numbers in the filename represent the left-most UTM easting coordinate (e###000) in meters, the next 4 numbers represent the top-most UTM northing coordinate (n####000) in meters, and the last 2 numbers (##) represent the UTM zone in which the tile is located (ex. fs_e123_n4567_18). The development of custom software for creating these data products has been supported by the U.S. Geological Survey CMGP's Decision Support for Coastal Science and Management project. Processed data products are used by the U.S. Geological Survey CMGP'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.
20090528
ground condition
None planned
-8.091780716328438 E+1
-8.089724106635173 E+1
2.90903637237594 E+1
2.90722978674335 E+1
5.0800 E+5
5.1000 E+5
3.21800 E+6
3.21600 E+6
ISO 19115 Topic CategoryelevationGeneralAirborne Lidar Processing System
ALPSDigital Elevation ModelDEMEAARLExperimental Advanced Airborne Research Lidarlaser altimetrylidarremote sensingtopographyPilatus PC-6
GeneralFloridaAtlantic CoastCape CanaveralCanaveral National Seashore
GeneralFirst SurfaceGeneral2009
None
The U.S. Geological Survey and National Aeronautics and Space Administration request to be acknowledged as originators of this data in future products or derivative research.
mailing and physical address
600 4th Street South
St. Petersburg
FL
33701
USA
727 803-8747 (x3026)
M-F, 9:00-5:00 EST
Amar NayegandhiJacobs Technology, U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FLanayegandhi@usgs.gov727-803-2031Project Manager/Remote Sensing Specialist
Acknowledgment of the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, as a data source would be appreciated in products developed from these data, and such acknowledgment 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 ArcCatalog 9.2.2.1350
UnclassifiedUnclassifiedNone
The expected accuracy of the measured variables is as follows: attitude within 0.07 degree, 3-centimeter nominal ranging accuracy, and vertical elevation accuracy of +/-15 centimeters for the topographic surface. Quality checks are built into the data-processing software.
Raw elevation measurements have been determined to be within 1 meter in horizontal accuracy.
Typical vertical elevation accuracies for these data are consistent with the point elevation data, +/-15 centimeters. However, a ground-control survey is not conducted simultaneously with every lidar survey. Vertical accuracies may vary based on the type of terrain and the accuracy of the GPS and aircraft-attitude measurements.
The data are collected using a Pilatus PC-6 aircraft. The NASA Experimental Advanced Airborne Research Lidar (EAARL) laser scanner collects the data using a green (532-nanometer) 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, Florida and the NASA office at Wallops Flight Facility in Virginia. The navigational data are processed at Wallops Flight Facility. The navigational and raw data are then downloaded into the Airborne Lidar Processing System (ALPS, 20090903 - 20101021). 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).
20090528 through 20101021mailing and physical address600 4th Street SouthSaint PetersburgFL33701USA727-803-8747 (x3124)M-F, 8:00-5:00 ESTLidar Analystjcormier@usgs.govJamie M. Bonisteel-CormierJacobs Technology, U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL
Data Analystmailing and physical address600 4th Street SouthSt. PetersburgFL33701USA727-803-8747 (x3089)M-F, 8:30-4:30 ESTEmily KlippJacobs Technology, U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FLeklipp@usgs.govMetadata imported into ArcCatalog from XML file.20101022Amar NayegandhiJacobs Technology, U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FLComputer Scientistmailing and physical address600 4th Street SouthSt. PetersburgFL33701USA727 803-8747 (x3026)anayegnadhi@usgs.govM-F, 8:00-5:00 ESTSynchronously (or nearly synchronously) with the airborne mission, a ground-based GPS-survey system was used to measure elevations along the beach, roads, and vegetated areas. The expected root mean square error (rmse) accuracy of these ground data was approximately 10 cm. Based on comparison to data collected for this mission, the mean offset between the ground-based surveys and first-surface lidar was 36 cm (lidar elevations higher than the ground-based measurements) and the rmse between the two measurements was 33.3 cm.20090528 through 20100831
Each file contains data located in a 2-kilometer by 2-kilometer tile, where the upper-left bound can be assessed quickly through the filename. The first 3 numbers in the filename represent the left-most UTM easting coordinate (e###000) in meters, the next 4 numbers represent the top-most UTM northing coordinate (n####000) in meters, and the last 2 numbers (##) represent the UTM zone in which the tile is located (ex. fs_e123_n4567_17).Several regions of the dataset are labeled as "No Data," which corresponds to a cell value of -32767 meters in the GeoTIFF 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. The presence of "No Data" values does not necessarily indicate an absence of land, rather an absence of survey coverage or the presence of prolific vegetation that the laser is not able to penetrate in order to return bare-earth data. This metadata file is generalized; each data file on this DVD has its own corresponding metadata file.
Point
row and column
1.000000
1.000000
meters
Universal Transverse Mercator0.999600-81.00000500000.0000017
North American Datum of 1983
Geodetic Reference System 80
6378137.000000
298.25722210100002
North American Vertical Datum of 1988
0.15
meters
Explicit elevation coordinate included with horizontal coordinates
https://pubs.usgs.gov/of/2009/1078/
The input parameters for the Random Consensus Filter (RCF) were: grid cell size (buffer) = 6 meters x 6 meters; vertical tolerance (vertical width) = 500 centimeters.
*.xyz
The "*" represents the file name. The file is .xyz ASCII tab-delimited.
Internally devised to maintain naming consistency.
X
UTM easting in meters
NAVD 88
varying value range
Y
UTM northing in meters
NAVD 88
varying value range
Z
Altitude in meters
NAVD 88
varying value range
mailing and physical address
600 4th Street South
Saint Petersburg
FL
33701
USA
727 803-8747
U.S. Geological SurveyAmar NayegandhiProject Manager/Remote Sensing SpecialistM-F, 8:00-5:00 EST
This 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, or for general or scientific purposes, nor shall the act of distribution constitute 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. Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights.
VaryASCIIXYZ1DVDDVDContact U.S. Geological SurveyVary
Contact U.S. Geological Survey for details.
20090528DS 585
20110407
mailing and physical address
St. Petersburg
FL
33701
600 4th Street SouthUSA
727 803-8747 (x3089)
Emily KlippJacobs Technology, U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FLM-F, 8:30-4:30 ESTData Analysteklipp@usgs.gov
FGDC Content Standards for Digital Geospatial Metadata
FGDC-STD-001-1998
local time