U.S. Geological Survey
20170324
Lidar-Derived Classified Point-Cloud for Coastal Topography—Assateague Island, Maryland and Virginia, Post-Hurricane Hermine, 10-12 September 2016
first
binary point cloud
U.S. Geological Survey Data Release
doi:10.5066/F7NP22NH
St. Petersburg, FL
U.S. Geological Survey
https://doi.org/10.5066/F7NP22NH
Binary point-cloud data were produced for Assateague Island, Maryland and Virginia, post-Hurricane Hermine, from remotely sensed, geographically referenced elevation measurements collected by Quantum Spatial using a Riegl VQ-880-G (532-nm wavelength circular scan and 1064-nm wavelength linear scan) lidar sensor.
The purpose of this project was to produce a highly detailed and accurate digital elevation map for Assateague Island, Maryland and Virginia for use as a management tool and to make these data available to natural-resource managers and research scientists. To ensure that SPCMSC data management protocols were followed, this survey was assigned a USGS field activity number (FAN), 16CNT03. Additional survey and data details are available at http://cmgds.marine.usgs.gov/fan_info.php?fan=16CNT03. USGS Contract: G16PC00016 Task Order Number: G16D01063
Processed data products are used by the U.S. Geological Survey (USGS) CMGP's National Assessment 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.
U.S. Geological Survey National Geospatial Program lidar Base Specification, Version 1.2
Riegl VQ-880-G
Unlimited
0.7
2
0.7
2
500
120
40
160
245
1.3
35
532
0
0.7
364
50
National Geodetic Survey (NGS) Geoid12B
19.6
0.072
13
1.4
6
Withheld (ignore) points were identified in these files using the standard LAS Withheld bit
Swath overage points were identified in these files using the standard LAS overlap bit
16
1
Processed, but Unclassified
2
Bare earth ground
7
Low Noise
17
Bridge Decks
40
Bathymetric Bottom
41
Water Surface
45
Water Column
20160910
20160912
ground condition
None planned
USGS Metadata Identifier
USGS:86f6d7f7-0ab5-4779-b611-d1d293d1b775
ISO 19115 Topic Category
elevation
None
Digital Elevation Model
DEM
extratropical cyclone
laser altimetry
lidar
Cessna Caravan
remote sensing
shoreline
submerged topography
topography
Global Change Master Science Directory
LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION
OCEAN > COASTAL PROCESSES > BARRIER ISLANDS
OCEAN > COASTAL PROCESSES > BEACHES
OCEAN > COASTAL PROCESSES > SHORELINE DISPLACEMENT
DOI/USGS/CMG > COASTAL AND MARINE GEOLOGY, U.S. GEOLOGICAL SURVEY, U.S. DEPARTMENT OF INTERIOR
GCMD Instrument
lidar > LIGHT DETECTION AND RANGING
Geographic Names Information System
Assateague Island
Maryland
Virginia
Delmarva Peninsula
United States
None
Bare Earth
Submerged
None
2016
Post-Hurricane Hermine
None
Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. The U.S. Geological Survey requests to be acknowledged as originator of these data in future products or derivative research.
Xan Fredericks
U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL
Cartographer/Lidar Coordinator
mailing and physical address
600 4th Street South
St. Petersburg
FL
33701
USA
727 502-8086
727 502-8182
afredericks@usgs.gov
M-F, 8:00-4:00 ET
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. Sharing of 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 periods may be inaccurate because of 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.
Unclassified
Unclassified
None
Microsoft Windows 7 Enterprise Service Pack 1; Esri ArcCatalog 10.2.2.3552
-75.42335013
-75.07955612
38.33510704
37.83868211
Quantum Spatial reports that data cover the entire area specified for this project, approximately 52,196.2 acres.
Quantum Spatial reports that the contract specifications required that raw Non-vegetated Vertical Accuracy (NVA) be computed from the both the raw lidar point cloud swath files and the derived DEMs. Additionally, Vegetated Vertical Accuracy (VVA) was also to be computed from the derived DEMS. The NVA was tested with 13 independent check points provided to QSI by USGS located in open terrain, and distributed throughout the project as feasible. These check points were not used in the calibration or post processing of the lidar point cloud data. The VVA was tested with 12 independent check points, also provided to QSI by USGS, located in vegetated terrain and also witheld from the calibration and post processing of the lidar point cloud data. VVA points were also distributed throughout the project area as feasible. Specifications for this project require that the NVA be 19.6 meters or better AccuracyZ at 95% confidence level and that the VVA be 29.4 cm or better AccuracyZ at the 95th percentile. NVA Root Mean Square Error (RMSE) was calculated using the 13 independent check points provided by the USGS and resulted in a value of 0.072m.
0.072 meters AccuracyZ at the 95 percent Confidence Interval for Raw LAS NVA. 0.063 meters AccuracyZ at the 95 percent Confidence Interval for DEM NVA. 0.137 meters AccuracyZ at the 95th percentile for DEM VVA.
0.072 meters AccuracyZ at the 95 percent Confidence Interval for Raw LAS NVA. 0.063 meters AccuracyZ at the 95 percent Confidence Interval for DEM NVA. 0.137 meters AccuracyZ at the 95th percentile for DEM VVA. Quantum Spatial reports that the 13 independent NVA check points were surveyed using the closed level loop technique. Elevations interpolated from the unclassified lidar surface were compared to the elevation values of the surveyed NVA check points. The RMSE was computed to be 0.037 meters resulting in an AccuracyZ at the 95% confidence level of 0.072 meters. The 13 NVA check points were also compared to the elevations of the derived bare earth DEMs. The RMSE was computed to be 0.032 meters resulting in an AccuracyZ of 0.063 meters at the 95% confidence level. NVA AccuracyZ has been tested and meets the required 19.6 meter NVA at 95% confidence level using (RMSEz * 1.9600) for both the raw lidar point cloud and derived DEMs, as defined by the National Standards for Spatial Data Accuracy (NSSDA) and herein reported using National Digital Elevation Program (NDEP)/ASPRS Guidelines. The 13 VVA check points were also surveyed using the closed level loop technique. Elevations for these points were compared to the elevations of the derived bare earth DEMs. The RMSE was computed to be 0.078 meters resulting in an AccuracyZ of 0.137 meters at the 95th percentile. AccuracyZ has been tested on the derived bare earth DEMs and meets the required 29.4 meter VVA using the 95th percentile of the absolute value of all vertical errors in all combined vegetation classes as defined by the National Standards for Spatial Data Accuracy (NSSDA); and herein reported using National Digital Elevation Program (NDEP)/ASPRS Guidelines.
Quantum Spatial reports the following steps for Lidar Pre-Processing:
1. Review flight lines and data to ensure complete coverage of the study area and positional accuracy of the laser points.
2. Resolve kinematic corrections for aircraft position data using kinematic aircraft GPS and static ground GPS data.
3. Develop a smoothed best estimate of trajectory (SBET) file that blends post-processed aircraft position with sensor head position and attitude recorded throughout the survey.
4. Calculate laser point position by associating SBET position to each laser point return time, scan angle, intensity, etc. Create raw laser point cloud data for the entire survey in *.las format. Convert data to orthometric elevations by applying a geoid correction.
5. Import raw laser points into manageable blocks to perform manual relative accuracy calibration and filter erroneous points. Apply the refraction correction necessary for bathymetric data. Classify ground/bathymetric points for individual flight lines.
6. Using ground classified points per each flight line, test the relative accuracy. Perform automated line-to-line calibrations for system attitude parameters (pitch, roll, heading), mirror flex (scale) and GPS/IMU drift. Calculate calibrations on ground classified points from paired flight lines and apply results to all points in a flight line. Use every flight line for relative accuracy calibration.
7. Adjust the point cloud by comparing ground classified points to supplemental ground control points.
Base_Station_Control, SBETs, SGCPs, RAW_lidar
20161130
Quantum Spatial
mailing and physical
517 SW 2nd Street, Suite 400
Corvallis
OR
97333
USA
541-752-1204
541-752-3770
Monday through Friday 8:30 AM to 5:00 PM (Pacific Standard Time)
Quantum Spatial reports the following steps for Lidar Post-Processing:
1. Classify data to ground and other client designated classifications using proprietary classification algorithms.
2. Manually QC data classification
3. After completion of classification and final QC approval, calculate density information and verify final accuracy calculations for the project using ground control quality check points.
Base_Station_Control, SBETs, QCPs, RAW_lidar
20161130
Classified_lidar
Quantum Spatial
mailing and physical
517 SW 2nd Street, Suite 400
Corvallis
OR
97333
USA
541-752-1204
541-752-3770
Monday through Friday 8:30 AM to 5:00 PM (Pacific Standard Time)
Added keywords section with USGS persistent identifier as theme keyword.
20201013
U.S. Geological Survey
VeeAnn A. Cross
Marine Geologist
Mailing and Physical
384 Woods Hole Road
Woods Hole
MA
02543-1598
508-548-8700 x2251
508-457-2310
vatnipp@usgs.gov
Quantum Spatial reports that these LAS files include all data points collected. No points have been removed or excluded. Shaded relief images have been visually inspected for data errors such as pits, border artifacts, and shifting. Lidar flight lines have been examined to ensure consistent elevation values across overlapping flight lines. The raw point cloud is of good quality and data passes Vertical Accuracy specifications.
Vector
Point
Universal Transverse Mercator
18
0.999600
-75.000000
0
500000.000000
0
coordinate pair
0.01
0.01
meters
North American Datum of 1983 (2011)
Geodetic Reference System 80
6378137.000000
298.25722210100002
North American Vertical Datum of 1988 (GEOID12B)
0.01
meters
Explicit elevation coordinate included with horizontal coordinates
U.S. Geological Survey
Xan Fredericks
Cartographer/Lidar Coordinator, U.S. Geological Survey
mailing and physical address
600 4th Street South
St. Petersburg
FL
33701
USA
727 502-8086
M-F, 8:00-4:00 ET
ASIS2016_HRHM_SM_z18_n88g12B_classified.laz
Although these data have been processed successfully on a computer system at the USGS, 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 USGS shall not be held liable for improper or incorrect use of the data described and/or contained herein. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Compressed LAS (LAZ)
Compressed LAS (LAZ)
1.4
https://coastal.er.usgs.gov/data-release/doi-F7NP22NH/data/ASIS2016_HRHM_SM_z18_n88g12B_classified.zip
None
Contact U.S. Geological Survey for details.
20201102
Xan Fredericks
U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL
Cartographer/Lidar Coordinator
mailing and physical address
600 4th Street South
St. Petersburg
FL
33701
USA
727 502-8086
afredericks@usgs.gov
M-F, 8:00-4:00 ET
Content Standard for Digital Geospatial Metadata
FGDC-STD-001-1998
local time