U.S. Geological Survey
20130904
Topographic Lidar Survey of Dauphin Island, Alabama and Chandeleur, Stake, Grand Gosier and Breton Islands, Louisiana, July 12-14, 2013 -- Classified Point Data
binary point cloud
U.S. Geological Survey Data Series
838
St. Petersburg, Fla.
U.S. Geological Survey
http://pubs.usgs.gov/ds/0838/
A topographic lidar survey was conducted July 12-14, 2013 over Dauphin Island, Alabama and Chandeleur, Stake, Grand Gosier and Breton Islands, Louisiana.
Lidar data exchange format (LAS) 1.2 formatted classified point data files were generated based on these data.
Photo Science, Inc. was contracted by the U.S. Geological Survey (USGS) to collect and process the lidar data.
The lidar data were collected at a nominal pulse spacing (NPS) of 1.0 meter (m).
The horizontal projection and datum of the data are Universe Transverse Mercator, zone 16N, North American Datum 1983 (UTM Zone 16N NAD83), meters. The vertical datum is North American Vertical Datum 1988, Geoid 2012a (NAVD88, GEOID12A), meters.
Eighty-five LAS files, based on a 2-kilometer by 2-kilometer tiling scheme, cover the entire survey area.
These lidar data are available to Federal, State and local governments, emergency-response officials, resource managers, and the general public.
Lidar_Information
Lidar_Collection_Information
Lidar_Specification USGS-NGP Base Lidar Specification v1.0
Lidar_Sensor Leica ALS 70
Lidar_Maximum_Returns 4
Lidar_Pulse_Spacing 0.64
Lidar_Density 1.57
Lidar_Flight_Height 1524
Lidar_Flight_Speed 130
Lidar_Scan_Angle 20.0
Lidar_Scan_Frequency 29.6
Lidar_Pulse_Rate 178.4
Lidar_Pulse_Duration 4
Lidar_Pulse_Width 0.35
Lidar_Central_Wavelength 1064
Lidar_Multiple_Pulses_In_Air 0
Lidar_Beam_Divergence 0.22
Lidar_Swath_Width 1109.38
Lidar_Swath_Overlap 11.46%
Lidar_Coordinate_Reference_System_Name NAD_1983_UTM_Zone_16N_Meters
Lidar_Geoid National Geodetic Survey (NGS) Geoid03
Lidar_Accuracy_Information
Lidar_Calculated_Horizontal_Accuracy 0.012
Lidar_Raw_Fundamental_Vertical_Accuracy 0.01
Lidar_LAS_Information
Lidar_LAS_Version 1.2
Lidar_LAS_Point_Record_Format 1
Lidar_LAS_Witheld_Point_Identifier Withheld (ignore) points were identified in these files using the standard LAS Withheld bit.
Lidar_LAS_Overage_Point_Identifier Swath "overage" points were identified in these files by adding 16 to the standard classification values.
Lidar_LAS_Radiometric_Resolution 8
Lidar_LAS_Classification
Lidar_LAS_Class_Code 1
Lidar_LAS_Class_Description Processed, but unclassified
Lidar_LAS_Classification
Lidar_LAS_Class_Code 2
Lidar_LAS_Class_Description Bare earth ground
Lidar_LAS_Classification
Lidar_LAS_Class_Code 7
Lidar_LAS_Class_Description Noise
Lidar_LAS_Classification
Lidar_LAS_Class_Code 9
Lidar_LAS_Class_Description Water
Lidar_LAS_Classification
Lidar_LAS_Class_Code 10
Lidar_LAS_Class_Description Ignored ground
Lidar_LAS_Classification
Lidar_LAS_Class_Code 17
Lidar_LAS_Class_Description Overlap default (unclassified)
Lidar_LAS_Classification
Lidar_LAS_Class_Code 18
Lidar_LAS_Class_Description Overlap bare-earth ground
This lidar survey was acquired to document the short- and long-term changes of several different barrier island systems. Specifically, this survey supports detailed studies of Chandeleur and Dauphin Islands that resolve annual changes in beaches, berms and dunes associated with processes driven by storms, sea-level rise, and even human restoration activities.
Lidar data acquisition, calibration, and follow-on processing were completed by Photo Science, Inc. Photo Science was contracted by the U.S. Geological Survey to conduct the work.
The geographic extent of each tile falls on even 2000 x and y UTM Zone 16N NAD83 meters.
The tile names are assigned according to the U.S. National Grid (USNG) spatial address (http://www.fgdc.gov/usng/how-to-read-usng/index_html).
The last 6 digits of the file name are based on the lower-left (LL) xy coordinate of the tile.
For example, tile name 16RCU324308 uses 324 to represent an LL x-coordinate of 324,000, and uses 308 to represent an LL y-coordinate of 3,308,000 (ignoring the first digit).
20130712
20130714
ground condition
None planned
-89.2054218436926
-88.0228864379435
30.3016091270762
29.4515909261428
USGS Metadata Identifier
USGS:8ddfaf9a-187f-4aa1-8cfc-1da8352009ff
None
model
remote sensing
elevation data
lidar
topography
hydrology
laser altimetry
bare earth
Global Change Master Science Directory (GCMD)
LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION
OCEAN > COASTAL PROCESSES > BARRIER ISLANDS
COASTAL PROCESSES > BEACHES
DOI/USGS/CMG > COASTAL AND MARINE GEOLOGY, U.S. GEOLOGICAL SURVEY, U.S. DEPARTMENT OF INTERIOR
GCMD Instrument
LIDAR > LIGHT DETECTION AND RANGING
Data Categories for Marine Planning
distributions
bathymetry and elevation
Marine Realms Information Bank (MRIB) Keywords
altimetry
topographic mapping
USGS Thesaurus
LIDAR
topography
digital elevation models
None
Alabama
Louisiana
Gulf of Mexico
Barrier Islands
Gulf of Mexico Barrier Islands
Stake Island
Grand Gosier Island
Breton Island
Chandeleur Islands
Dauphin Island
United States
General
2013
No restrictions apply to these data.
None. However, users should be aware that temporal changes may have occurred since this dataset was collected and some parts of these data may no longer represent surface conditions. Users should not use these data for critical applications without a full awareness of its limitations. Acknowledgement of the U.S. Geological Survey would be appreciated for products derived from these data.
U.S. Geological Survey
Nathaniel Plant
mailing and physical
600 4th St. S.
St. Petersburg
FL
33701
USA
727-803-8747
727-803-2031
nplant@usgs.gov
Monday through Friday 9:00 AM to 5:00 PM (Eastern Time)
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. 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 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.
Contractor: MicroStation Version 8; TerraScan Version 13; TerraModeler Version 13; GeoCue Version 2012.1.27.7; ESRI ArcGIS 10.1; Global Mapper 13; ALS Post Processor 2.75 Build #25; Windows 7 Operating System
Classified LAS files were tested by Photo Science for both vertical and horizontal accuracy. All data is seamless from one tile to the next; no gaps or no-data areas.
Datasets contain complete coverage of tiles.
No points have been removed or excluded.
A visual qualitative assessment was performed to ensure data completeness.
There are no void areas or missing data. The raw point cloud is of good quality and data passes fundamental vertical accuracy (FVA) specifications.
FVA was computed for raw lidar point cloud swath files.
The vertical accuracy was tested with 10 independent survey checkpoints located in open terrain. These checkpoints were used in the calibration and post processing of the lidar point cloud data. The survey checkpoints were distributed throughout the project area. Specifications for this project require that the FVA be 18.13cm or better AccuracyZ at 95 percent confidence level.
1.2 centimeters AccuracyZ at 95 percent Confidence Interval
The data was tested using 10 independent survey located in open terrain. The survey checkpoints were distributed throughout the project area. The 10 independent checkpoints were surveyed by the USGS St. Petersburg Coastal and Marine Science Center, St. Petersburg, Fla. office, using GPS techniques. Elevations from the unclassified lidar surface were measured for the x,y location of each check point. Elevations interpolated from the lidar surface were then compared to the elevation values of the surveyed control. The RMSEz was computed to be 0.012 m. AccuracyZ has been tested to meet 18.13 cm FVA at 95 percent confidence level using RMSEz x 1.9600 as defined by the National Standards for Spatial Data Accuracy (NSSDA); assessed and reported using National Digital Elevation Program (NDEP)/ASRPS Guidelines.
Photo Science, Inc.
20130904
Lidar Raw Data for Gulf of Mexico Barrier Islands
lidar data
Photo Science, Inc.
Photo Science, Inc., Aerial LiDAR Department
digital hard drive
20130712
20130714
ground condition
Raw Lidar Data
This data source was used to populate the lidar point cloud data.
U.S. Geological Survey
2013
Ground Control Points
online
20130714
20130723
ground condition
Ground Control Points
This data source was used in lidar processing and accuracy assessment. This dataset is not included in this Data Series Report.
Lidar Pre-Processing: Airborne global positioning system (GPS) and inertial measurement units (IMU) data were merged to develop a Single Best Estimate (SBET) of the lidar system trajectory for each lift. Lidar ranging data were initially calibrated using previous best parameters for this instrument and aircraft. Relative calibration was evaluated using advanced plane-matching analysis and parameter corrections were derived. This was repeated iteratively until residual errors between overlapping swaths, across all project lifts, was reduced to acceptable levels. Data were then block adjusted to match surveyed calibration control. Raw data FVA was checked using independently surveyed checkpoints. Swath overage points were identified and tagged within each swath file.
The raw lidar data and the ground control points are intermediary datasets and are not included in this Data Series Report.
Raw Lidar Data
Ground Control Points
2013
Calibrated Lidar Datasets
Photo Science, Inc.
mailing and physical
523 Wellington Way
Lexington
KY
40503
USA
859-277-8700
859-277-8901
Monday through Friday 8:00 AM to 5:00 PM (Eastern Time)
If unable to reach the contact by telephone, please send an email. You should receive a response within 24 hours.
Lidar Post-Processing: The calibrated and controlled lidar swaths were processed using automatic point classification routines in proprietary software. These routines operate against the entire collection (all swaths, all lifts), eliminating character differences between files. Data were then distributed as virtual tiles to experienced lidar analysts for localized automatic classification, manual editing, and peer-based quality control (QC) checks. Supervisory QC monitoring of work in-progress and completed editing ensured consistency of classification character and adherence to project requirements across the entire project area. All classification tags are stored in the original swath files.
Calibrated Lidar Datasets
2013
Classified Lidar Datasets
Photo Science, Inc.
mailing and physical
523 Wellington Way
Lexington
KY
40503
USA
859-277-8700
859-277-8901
bishop@photoscience.com
Monday through Friday 8:00 AM to 5:00 PM (Eastern Time)
If unable to reach the contact by telephone, please send an email. You should receive a response within 24 hours.
The bare earth surface is manually reviewed to ensure correct classification on the Class 2 (Ground) points. After the bare-earth surface is finalized, it is used to generate all hydro-breaklines through heads-up digitization.
All ground (ASPRS Class 2) lidar data inside of the Lake Pond and Double Line Drain hydro flattening breaklines were then classified to water (ASPRS Class 9) using TerraScan macro functionality. A buffer of 1 m was used around each hydro-flattened feature to classify these ground (ASPRS Class 2) points to Ignored ground (ASPRS Class 10). All Lake Pond Island and Double Line Drain Island features were checked to ensure that the ground (ASPRS Class 2) points were reclassified to the correct classification after the automated classification was completed.
All overlap data was processed through automated functionality provided by TerraScan to classify the overlapping flight line data to classes approved by USGS. The overlap data was classified to Class 17 (Overlap Default) and Class 18 (Overlap Ground). These classes were created through automated processes only and were not verified for classification accuracy. Due to software limitations within TerraScan, these classes were used to trip the withheld bit within various software packages. These processes were reviewed and accepted by USGS.
All data was manually reviewed and remaining artifacts removed using functionality provided by TerraScan and TerraModeler. Global Mapper was used as a final check of the bare earth dataset. GeoCue was then used to create the deliverable industry-standard LAS files for both the All Point Cloud Data and the Bare Earth. Photo Science proprietary software was used to perform final statistical analysis of the classes in the LAS files, on a per tile level to verify final classification metrics and full LAS header information.
Classified Lidar Datasets
2013
Validated LAS Datasets
Photo Science, Inc.
mailing and physical
523 Wellington Way
Lexington
KY
40503
USA
859-277-8700
859-277-8901
bishop@photoscience.com
Monday through Friday 8:00 AM to 5:00 PM (Eastern Time)
If unable to reach the contact by telephone, please send an email. You should receive a response within 24 hours.
Hydro Classification Breakline Processing:
Class 2 lidar was used to create a bare earth surface model. The surface model was then used to heads-up digitize 2D breaklines of inland streams and rivers with a 30 meter nominal width and inland ponds and Lakes of 8,000 square meters or greater surface area.
The breaklines were collected for classification purposes only. The provided breaklines are 2D features, and do not contain a valid elevation attribute.
All ground (ASPRS Class 2) lidar data inside of the collected inland breaklines were then classified to water (ASPRS Class 9) using TerraScan macro functionality. A buffer of 1 meter was also used around each breakline feature. These points were moved from ground (ASPRS Class 2) to ignored ground (ASPRS Class 10).
The breakline files were then translated to ESRI Shapefile format using ESRI conversion tools.
Validated LAS Datasets
2013
Hydro Classification Breaklines
Photo Science, Inc.
mailing and physical
523 Wellington Way
Lexington
KY
40503
USA
859-277-8700
859-277-8901
bishop@photoscience.com
Monday through Friday 8:00 AM to 5:00 PM (Eastern Time)
If unable to reach the contact by telephone, please send an email. You should receive a response within 24 hours.
Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog.
20170104
U.S. Geological Survey
Alan O. Allwardt
Contractor -- Information Specialist
mailing and physical address
2885 Mission Street
Santa Cruz
CA
95060
831-460-7551
831-427-4748
aallwardt@usgs.gov
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
Tile Index
Point
Point
Universal Transverse Mercator
16
0.9996
-87.000000
0.0
500000
0.0
coordinate pair
0.01
0.01
meters
North American Datum of 1983
Geodetic Reference System 80
6378137
298.257222101
North American Vertical Datum of 1988
0.01
meters
Explicit elevation coordinate included with horizontal coordinates
*.las
LAS 1.2 files. The asterisk represents the unique file identifier (See Supplemental Information section).
Photo Science, Inc.
X
UTM zone 16N NAD83 easting in meters.
UTM zone 16N NAD83 coordinate system
varying value range
Y
UTM zone 16N NAD83 northing in meters.
UTM zone 16N NAD83 coordinate system
varying value range
Z
NAVD88 GEOID12a elevation in meters.
NAVD88 GEOID12a
varying value range
Intensity
The intensity value is the integer representation of the pulse return magnitude. This value is optional and system specific.
ASPRS
Integers of varying value range
Return Number
The Return Number is the pulse return number for a given output pulse. A given output laser pulse can have many returns, and they must be marked in sequence of return. The first return will have a Return Number of one, the second a Return Number of two, and so on up to five returns.
ASPRS
1
5
Number of Returns
The Number of Returns is the total number of returns for a given pulse. For example, a laser data point may be return two (Return Number) within a total number of five returns.
ASPRS
1
5
Scan Direction Flag
The Scan Direction Flag denotes the direction at which the scanner mirror was traveling at the time of the output pulse. A bit value of 1 is a positive scan direction, and a bit value of 0 is a negative scan direction, where positive scan direction is a scan moving from the left side of the in-track direction to the right side and negative is the opposite.
ASPRS
0
1
Edge of Flight Line
The Edge of Flight Line data bit has a value of 1 only when the point is at the end of a scan. It is the last point on a given scan line before it changes direction.
UTM zone 16N NAD83 coordinate system
0
1
Classification
These data were specifically processed for bare earth (ground). Refer to "Process Steps" for additional information on classification.
ASPRS and Photo Science
0
Created, never classified
ASPRS
1
Unclassified
ASPRS
2
Ground
ASPRS
7
Low point (noise)
ASPRS
9
Water
ASPRS
10
Ignored ground
Photo Science, Inc.
11
Reserved
Photo Science, Inc.
17
Overlap default
Photo Science, Inc.
18
Overlap ground
ASPRS
25
Reserved
Photo Science, Inc.
Scan Angle Rank
The Scan Angle Rank is a signed one-byte number with a valid range from -90 to 90.
The Scan Angle Rank is the angle (rounded to the nearest integer in the absolute value sense)at which the laser point was output from the laser system including the roll of the aircraft.
The scan angle is within 1 degree of accuracy from -90 to 90 degrees.
Zero degrees is the nadir and -90 degrees is to the left side of the aircraft in the direction of flight.
ASPRS
-90
90
User Data
This field may be used at the user's discretion.
ASPRS
undefined
Point Source ID
This value indicates the file from which this point originated. Valid values for this field are 1 to 65,535 inclusive with zero being used for a special case discussed below. The numerical value corresponds to the File Source ID from which this point originated. Zero is reserved as a convenience to system implementers. A Point Source ID of zero implies that this point originated in this file. This also implies that processing software should set the Point Source ID equal to the File Source ID of the file containing this point at some time during processing.
ASPRS
1
65,535
GPS Time
The GPS Time is the double floating point time tag value at which the point was acquired. It is GPS Week Time if the Global Encoding low bit is clear and POSIX Time if the Global Encoding low bit is set
ASPRS
varying value range
Nathaniel Plant
U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, Fla.
Research Oceanographer
mailing and physical address
600 4th Street South
St. Petersburg
FL
33701
USA
727-803-8747
Monday-Friday, 9:00-5:00 Eastern Time
DS 838
Although these data were 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.
LAS, zipped
http://pubs.usgs.gov/ds/0838/
None if obtained online; otherwise prices vary.
Publications are available from USGS Information Services, Box 25286, Federal Center, Denver, CO 80225-0046 (telephone: 1-888-ASK-USGS, e-mail: infoservices@usgs.gov).
20201013
U.S. Geological Survey
K. Guy
mailing and physical
600 4th Street South
St. Petersburg
FL
33701
USA
727-803-8747
727-803-2031
kguy@usgs.gov
Monday through Friday 9:00 AM to 5:00 PM (Eastern Time)
FGDC Content Standard for Digital Geospatial Metadata
FGDC-STD-001-1998
None.
None.
None.
Unclassified
NONE