Original Data:
These files contain classified topographic and bathymetric lidar data as unclassified valid topographic data (1), valid topographic data classified as ground (2), invalid topographic data classified as low points (7), water (9), points that fall in topographic areas that were acquired with the bathymetric sensor (21), valid bathymetric data (29). Classes 1,2,7,9 are defined in accordance with the American Society for Photogrammetry and Remote Sensing (ASPRS) classification standards, while classes 21 and 29 are classes specific to the data collection. These data were collected with a RIEGL VQ-480 and a Coastal Zone Mapping and Imaging Lidar (CZMIL) airborne lidar system along the Lake Michigan shoreline. The VQ-480 sensor has a pulse repetition rate of 150 kHz at near infrared laser wavelength. CZMIL integrates a lidar sensor with topographic and bathymetric capabilities, a digital camera and a hyperspectral imager on a single remote sensing platform for use in coastal mapping and charting activities.
Data coverage generally extends along the shoreline from the waterline to 500 meters onshore. Native lidar data are 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 exported to standard formats and imported into GIS software for visualization and further analysis. Horizontal positions, provided in UTM Zone 16N coordinates in meters, are referenced to the NAD83 (2011) Epoch 2010 datum. Vertical elevations in meters are also referenced to this datum (GRS80 ellipsoidal height). The 3-D position data are sub-divided into a series of LAS files, each derived from a single flightline. 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 Datum of 1988 (NAVD88). Once converted to orthometric heights, the data are then converted to the International Great Lakes Datum of 1985 (IGLD85) using the VDatum program from NOAA (National Oceanic and Atmospheric Administration). 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.
In addition to the lidar point data, the topobathy bare earth Digital Elevation Models (DEMs) at a 1 meter grid spacing, created from the lidar point data, are also available from the NOAA Digital Coast Data Access Viewer (DAV). A link to the bare earth 1 meter DEM data is provided in the URL section of this metadata record. DEMs at a 1 meter grid spacing, created from all classifications, are available by request at coastal.info@noaa.gov.
This data set is an LAZ (compressed LAS) format file containing LIDAR point cloud data.