2011 U.S. Army Corps of Engineers (USACE) Topographic LiDAR: Massachusetts and New
This kmz file shows the extent of coverage for the 2011 USACE Topographic Lidar: MA
and NH lidar data set.
These files contain classified topographic and bathymetric lidar data as unclassified
valid topographic data (1), valid topographic data classified as ground (2), noise
(7), and valid bathymetric data (11). Classes 1, 2 and 7 aredefined in accordance
with the American Society for Photogrammetry and Remote Sensing (ASPRS) classification
standards, while class 11 is specific to NOAA CSC. These data were collected by the
Compact Hydrographic Airborne RapidTotal Survey (CHARTS) system along the coast of
Massachusetts and New Hampshire. CHARTS integrates topographic and bathymetric lidar
sensors, a digital camera and a hyperspectral imager on a single remote sensing platform
for usein coastal mapping and charting activities. Data coverage generally extends
along the coastline from the waterline inland 500 meters (topography) and offshore
1,000 meters or to laser extinction (bathymetry). Native lidar data isnot generally
in a format accessible to most Geographic Information Systems (GIS). Specialized in-house
and commercial software packages are used to process the native lidar data into 3-dimensional
positions that can be importedinto GIS software for visualization and further analysis.
Horizontal positions, provided in decimal degrees of latitude and longitude, are referenced
to the North American Datum of 1983 (NAD83). Vertical positions are referencedto the
NAD83 ellipsoid and provided in meters. The National Geodetic Survey's (NGS) GEOID03
model is used to transform the vertical positions from ellipsoid to orthometric heights
referenced to the North American Vertical Datumof 1988 (NAVD88). The 3-D position
data are sub-divided into a series of LAS files, each covering approximately 5 kilometers
of shoreline. The format of the file is LAS version 1.2.
Cite this dataset when used as a source.
|Search and Download
|| Distributor information not available
| Point of Contact
Documentation links not available.
|Data Presentation Form:
|| Digital image
|Dataset Progress Status
|Data Update Frequency:
|| As needed
||These data covered the required survey area with minimal gaps in data coverage except
where poor water quality prohibited bathymetric data acquisition. In areas of dense
vegetation the points classified as ground might be incorrectly classified due to
the inability of the laser to penetrate the canopy and reach the bare ground.
||These data were collected as a part of the NCMP to depict the elevations above and
below the water in the Massachusetts and New Hampshire coastal zone.
||2011-09-25 to 2011-09-30
|Spatial Reference System:
|Spatial Bounding Box Coordinates:
|Spatial Coverage Map:
- Remote Sensing
- U.S. Army Corps of Engineers (USACE)
- Mobile District
- National Coastal Mapping Program (NCMP)
- Classified LAS
- Classified LAZ
- Scanning Hydrographic Operational Airborne Lidar System (SHOALS)
- Compact Hydrographic Airborne Rapid Total Survey (CHARTS)
- Joint Airborne Lidar Bathymetry Technical Center of eXpertise (JALBTCX)
- Essex County
- New Hampshire
- Rockingham County
| Use Constraints
|| No constraint information available
|| Fee information not available.
|| Lineage statement not available.
| Processing Steps
- These data were collected using the CHARTS system. It is owned by the Naval Oceanographic
Office and operated through contract. The system collects topographic lidar data at
10 kHz, bathymetric lidar data at 1 kHz and RGBimagery at 1Hz. A CASI-1500 hyperspectral
line scanner is integrated with the system as well. Aircraft position, velocity and
acceleration information are collected through a combination of Novatel and POS A/V
410 equipment.All raw data streams are transferred to the office for downloading and
processing in SHOALS GCS software. Aircraft position data are processed using POSPac
software and the results are combined with the lidar data to produce3-D positions
for each lidar shot. Upon inspection and QA/QC in the software packages Fledermaus
and PFM_ABE, anomalous data are flagged as invalid. PFM_ABE's charts2las module then
converts all valid data from ellipsoid toorthometric heights based on the NGS' GEOID03
model and exports topographic and bathymetric data as a series of LAS files, one file
per flight line. The format of the file is LAS version 1.2. Data are classified as
0 (validtopographic data), 21 (valid topographic data acquired with the bathymetric
sensor), 27 (invalid topographic and bathymetric data), 29 (valid bathymetric data).
- The flightline LAS files are imported into GeoCue V184.108.40.206, which is a geospatial
workflow production and management software tool employed by JALBTCX to perform and
monitor production of data products. Upon import into GeoCue,the flightline LAS files
are divided into a series of boxes, each of which are 1500 meters in length and width.
A customized classification macro, built upon the TerraScan V11 module within Microstation
V8i, classifies validtopographic data as ground points (2) and unclassified points
(1). Upon completion the macro, the classification results undergo quality control
and any misclassified points are manually edited. In areas of dense vegetation thebare
earth ground points might be incorrectly classified due to the inability of the laser
to penetrate the canopy and reach the bare ground. In these areas, JALBTCX defaults
to the algorithms ground surface instead of manuallyreclassifying those points. The
final classification results are comprised of individual lidar points with classifications
of ground (2) or unclassified (1). They are partitioned into a series of 5km delivery
boxes, oneClassified LAS file per box. The format of the file is LAS version 1.2.
Data are classified as 1 (valid non-ground topographic data), 2 (valid ground topographic
data), 21 (valid topographic data acquired with the bathymetricsensor), 27 (invalid
topographic and bathymetric data), 29 (valid bathymetric data).
- The NOAA Coastal Services Center (CSC) received the las files from JALBTCX on hard
drive. The files contained lidar elevation and intensity measurements. The data were
received in Geographic, NAD83 coordinates and were vertically referenced to NAVD88
using the Geoid03 model. The vertical units of the data were meters. CSC performed
the following processing for data storage and Digital Coast provisioning purposes:1.
All points in Class 29 (valid bathymetry) were converted to Class 11. 2. The topographic
las files were compressed to laz v1.2 using LASTools' laszip software. 3. GPS Week
Time Information was converted to Adjusted Standard GPS Time using LASTools' las2las
software. 4. The topographic laz files were converted from orthometric (NAVD88) heights
to ellipsoidal heights using Geoid03.
- 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.
Metadata Last Modified: 2014-01-27
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