- Fugro EarthData, Inc.
- Fugro EarthData, Inc.
- Fugro EarthData, Inc.
- DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National
Oceanic and Atmospheric Administration, U.S. Department of Commerce
- DOC/NOAA/NESDIS/NCEI > National Centers of Environmental Information, NESDIS, NOAA,
U.S. Department of Commerce
- 2012-11-18T00:00:00 -
All acquired LiDAR data went through a preliminary review to assure that complete
coverage was obtained and that there were no gaps between flight lines before the
flight crew left the project site. Once back in the office, the data is run through
a complete iteration of processing to ensure that it is complete, uncorrupted, and
that the entire project area has been covered without gaps between flight lines. There
are essentially three steps to this processing: 1) GPS/IMU Processing - Airborne GPS
and IMU data was immediately processed using the airport GPS base station data, which
was available to the flight crew upon landing the plane. This ensured the integrity
of all the mission data. These results were also used to perform the initial LiDAR
system calibration test. 2) Raw LiDAR Data Processing - Technicians processed the
raw data to LAS format flight lines with full resolution output before performing
QC. A starting configuration file was used in this process, which contains the latest
calibration parameters for the sensor. The technician also generated flight line trajectories
for each of the flight lines during this process. 3) Verification of Coverage and
Data Quality - Technicians checked flight line trajectory files to ensure completeness
of acquisition for project flight lines, calibration lines, and cross flight lines.
The intensity images were generated for the entire lift at the required post spacing
for the project. The technician visually checked the intensity images against the
project boundary to ensure full coverage. The intensity histogram was analyzed to
ensure the quality of the intensity values. The technician also thoroughly reviewed
the data for any gaps in project area. The technician generated a few sample TIN surfaces
to ensure no anomalies were present in the data. Turbulence was inspected for and
if it affected the quality of the data, the flight line was rejected and reflown.
The technician also evaluated the achieved post spacing against project specified
- 2012-11-19T00:00:00 -
The boresight for each lift was done individually as the solution may change slightly
from lift to lift. The following steps describe the Raw Data Processing and Boresight
process: 1) Technician processed the raw data to LAS format flight lines using the
final GPS/IMU solution. This LAS data set was used as source data for boresight. 2)
Technician first used commercial software to calculate initial boresight adjustment
angles based on sample areas selected in the lift- mini project. These areas cover
calibration flight lines collected in the lift, cross tie and production flight lines.
These areas are well distributed in the lift coverage and cover multiple terrain types
that are necessary for boresight angle calculation. The technician then analyzed the
result and made any necessary additional adjustment until it is acceptable for the
mini project. 3) Once the boresight angle calculation was done for the mini project,
the adjusted settings were applied to all of the flight lines of the lift and checked
for consistency. The technician utilized commercial and proprietary software packages
to analyze the matching between flight line overlaps for the entire lift and adjusted
as necessary until the results met the project specifications. 4) Once the boresight
adjustment was completed for each lift individually, the technician ran a routine
to check the vertical misalignment of all flight lines in the project and also compared
data to ground truth. The entire dataset was then adjusted to ground control points.
5) The technician ran a final vertical accuracy check between the adjusted data and
surveyed ground control points after the z correction. The result was analyzed against
the project specified accuracy to make sure it meets the project requirements
- 2012-11-27T00:00:00 -
Once boresighting is complete for the project, the project was set up for classification.
The LiDAR data was cut to production tiles. The flight line overlap points, Noise
points and Ground points were classified automatically in this process. Fugro EarthData,
Inc. has developed a unique method for processing LiDAR data to identify and re-classify
elevation points falling on vegetation, building, and other above ground structures
into separate data layers. The steps are as follows: 1) Fugro EarthData, Inc. utilized
commercial software as well as proprietary software for automatic filtering. The parameters
used in the process were customized for each terrain type to obtain optimum results.
2) The Automated Process typically re-classifies 90-98% of points falling on vegetation
depending on terrain type. Once the automated filtering was completed, the files were
run through a visual inspection to ensure that the filtering was not too aggressive
or not aggressive enough. In cases where the filtering was too aggressive and important
terrain features were filtered out, the data was either run through a different filter
or was corrected during the manual filtering process. 3) Interactive editing was completed
in 3D visualization software which also provides manual and automatic point classification
tools. Fugro EarthData, Inc. used commercial and proprietary software for this process.
Vegetation and artifacts remaining after automatic data post-processing were reclassified
manually through interactive editing. The hard edges of ground features that were
automatically filtered out during the automatic filtering process were brought back
into ground class during manual editing. Auto-filtering routines were utilized as
much as possible within fenced areas during interactive editing for efficiency. The
technician reviewed the LiDAR points with color shaded TINs for anomalies in ground
class during interactive filtering. 4) All LAS tiles went through peer review after
the first round of interactive editing was finished. This helps to catch misclassification
that may have been missed by the interactive editing. 5) Upon the completion of peer
review and finalization of bare earth filtering, the classified LiDAR point cloud
work tiles went through a water classification routine based on the collected water
polygons. 6) The time stamps for all points were converted to Adjusted Standard GPS
time using proprietary software developed by Fugro EarthData, Inc. The data collection
date and the current GPS time stamp were used in calculating the Adjusted Standard
GPS time. 7) The classified point cloud data were packaged into geographic Coordinates,
NAD83(NA2011) in meters and the vertical datum is the North American Vertical Datum
of 1988 (NAVD88) in meters using GEIOD09 for delivery. The data was also cut to the
approved tile layout and clipped to the approved project boundary. The technician
checked the output LAS files for coverage and format; d) the technician then QCd the
dataset for quality assurance and enhanced the Bare Earth classification in the project
area for consistent data quality; ie) these final LiDAR tiles were then used in the
hydro flattening process. 8) classified LiDAR point cloud data are delivered in LAS
1.2 format: 1 unclassified, 2 ground, 7 low points, 8 model keypoints, 9 water, and
10 ignored points.
- 2013-01-01T00:00:00 -
The NOAA Coastal Services Center (CSC) received topographic files in LAS format. The
files contained lidar elevation and intensity measurements. The data were received
in Geographic (NAD83) coordinates and were vertically referenced to NAVD88 using the
Geoid12a model. The vertical units of the data were meters. CSC performed the following
processing for data storage and Digital Coast provisioning purposes: 1. The topographic
las files were converted from orthometric (NAVD88) heights to ellipsoidal heights
using Geoid12a. 2. The data were converted to LAZ format.
- 2013-02-20T00:00:00 -
The NOAA National Geophysical Data Center (NGDC) received lidar data files via ftp
transfer from the NOAA Coastal Services Center. The data are currently
being served via NOAA CSC Digital Coast at http://www.csc.noaa.gov/digitalcoast/.
The data can be used to re-populate the system. The data are archived in LAS or LAZ
The LAS format is an industry standard for LiDAR data developed by the American Society
of Photogrammetry and Remote Sensing (ASPRS); LAZ is a loseless compressed version
LAS developed by Martin Isenburg (http://www.laszip.org/). The data are exclusively
in geographic coordinates (either NAD83 or ITRF94). The data are referenced vertically
the ellipsoid (either GRS80 or ITRF94), allowing for the ability to apply the most
up to date geoid model when transforming to orthometric heights.