2009 US Army Corps of Engineers (USACE) Joint Airborne Lidar Bathymetry Technical
Center of Expertise (JALBTCX) Topobathy Lidar: Apostle Islands, WI
This kmz file shows the extent of coverage for the 2009 USACE Apostle Islands lidar
These files contain topographic and bathymetric lidar data collected by the Compact
Hydrographic Airborne Rapid Total Survey (CHARTS) system along the coast of Wisconsin.
CHARTS integrates topographic and bathymetric lidar sensors, a digital camera and
a hyperspectral scanner on a single remote sensing platform for use in 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). The topographic lidar sensor has a pulse repetition rate
of 9 kHz at 1064 nm (near-infrared wavelength). The bathymetric lidar sensor has a
pulse repetition rate of 1 kHz at 532 nm (green wavelength). Native lidar data is
not generally in a format accessible to most Geographical 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 imported into 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 were referenced to the NAD83 ellipsoid and provided in meters.
The National Geodetic Survey's (NGS) GEOID03 model was used to transform the vertical
positions from ellipsoid to orthometric heights referenced to the North American Vertical
Datum of 1988 (NAVD88). The format of the files was LAS version 1.0. The NOAA Coastal
Services Center received the data and converted the topo and hydro files from NAVD88
heights to ellipsoid heights using GEOID03. These files were converted for data storage
and Digital Coast provisioning purposes. The topographic points are classified as
0 (never classified) and the bathymetric points are classified as 11 (CSC bathymetry).
Cite this dataset when used as a source.
|Search and Download
|| Distributor information not available
| Point of Contact
Lidar Dataset Supplemental Information
|Data Presentation Form:
|| Digital image
|Dataset Progress Status
|Data Update Frequency:
|| As needed
||These data were collected as a part of the National Coastal Mapping Program (NCMP)
to depict the elevations above and below the water line in the Wisconsin coastal zone.
||2009-07-19 to 2009-08-02
|Spatial Reference System:
|Spatial Bounding Box Coordinates:
|Spatial Coverage Map:
- U.S. Army Corps of Engineers, Mobile District
- United States
- Ashland County
- Bayfield County
- Apostle Islands
- Lake Superior
| 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
9 kHz, bathymetric lidar data at 1 kHz and RGB imagery 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 produce 3-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 chartsLAS module then
converts all valid data from ellipsoid to orthometric heights based on the NGS' GEOID03
model and exports topographic data as a series of LAS files with a single file per
flightline per 5 km box and the bathymetric data files contain all of the returns
from the bathymetric sensor which includes returns both above and below the water.
- The NOAA Coastal Services Center (CSC) received the topo files in LAS v1.1 format
and the hydro files in ascii format. The files contained lidar elevation and intensity
measurements. The topo data were classified as 0 (never classified) and received in
geographic coordinates (NAD83) and vertically referenced to NAVD88 using the Geoid03
model. The vertical units of the data were meters. The hydro files were unclassified
and received in geographic coordinates (NAD83) and vertically referenced to NAVD88.
CSC performed the following processing for data storage and Digital Coast provisioning
purposes: 1. Both topo and hydro files were filtered for elevation outliers. 2. The
topo las files were converted from orthometric (NAVD88) heights to ellipsoidal heights
using Geoid03. 3. The hydro ascii files were converted from orthometric (NAVD88) heights
to ellipsoidal heights using Geoid03. 4. The hydro ascii files were converted from
ascii format to las format and the points were reclassified from 0 to 11 (Bathymetry).
5. The data were converted to LAZ format.
- 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: 2013-01-22
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