|2009 US Army Corps of Engineers (USACE) Joint Airborne Lidar Bathymetry Technical
Center of Expertise (JALBTCX) Topobathy Lidar: Apostle Islands, WI
||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).