2012 USACE Great Lakes Topobathy Lidar: Lake Michigan

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 lowpoints (7), valid bathymetric data (11), and valid topographic data acquired with the bathymetric sensor (14). Classes 1, 2, and 7 are defined in accordance with the American Society for Photogrammetry and Remote Sensing (ASPRS) classification standards, while classes 11 and 14 are classes specific to the NOAA Digital Coast Data Access Viewer (DAV).These data were collected with a RIEGL VQ-480 airborne lidar system along the Lake Michigan shoreline.

Data coverage generally extends along the shoreline from the waterline to 500 meters onshore. The VQ-480 sensor has a pulse repetition rate of 150 kHz at near infrared laser wavelength. 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 Geographic Coordinates in decimal degrees, 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. The National Geodetic Surveys (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). The 3-D position data are sub-divided into a series of LAS files, each covering approximately 5 kilometers of shoreline.

Note: The NOAA Office for Coastal Management was unable to determine the exact dates of collection due to corrupt GPS times in at least of the LAS files. Classifications listed from the original metadata above may have changed during processes at NOAA OCM.

These data were collected as a part of the NCMP to depict the elevations ABOVE AND/OR BELOW the water.

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A footprint of this data set may be viewed in Google Earth at:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/2644/supplemental/gl2012_usace_lakemichigan_m2644.kmz

LiDAR points in LAZ format (Classes 1,2,7,9,11,14)

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Any conclusions drawn from the analysis of this information are not the responsibility of USACE, JALBTCX, NOAA, the Office for Coastal Management or its partners.

This data can be obtained on-line at the following URL:

https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=2644;

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Users should be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions. Users should

not use this data for critical applications without a full awareness of its limitations. These data depict the heights at the time of the survey and are only accurate for that time.

The data point positions were obtained using post processed KGPS methods. The horizontal accuracy of the data is better than +/- 0.50 m; Quantitative Value: 0.50 meters, Test that produced the value: RMSE 95% Conf. Units in meters.

The data point positions were obtained using post processed KGPS methods. The vertical accuracy of the data is better than +/- 0.15 m; Quantitative Value: 0.15 meters, Test that produced the value: RMSE 95% Conf. Units in meters.

This data set covers the spatial extent of bathymetric and topographic lidar data obtained during this survey.

Differences between a DEM created from the lidar data representing bare ground and the ground truth point data is unbiased and within +/- 15 cm (RMSE) in flat terrain and within +/-30 cm

(RMSE) in hilly terrain