2013-2015 USACE NCMP Topobathy Lidar DEM: Lake Huron (MI)

These files contain rasterized topobathy lidar elevations generated from data collected by the Coastal Zone Mapping and Imaging Lidar (CZMIL) system. CZMIL integrates a lidar sensor with simultaneous 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. Horizontal positions, provided in decimal degrees of latitude and longitude, are referenced to the North American Datum of 1983 National Adjustment of 2011 (NAD83 NA2011). Vertical positions are referenced to the NAD83 NA11 ellipsoid and provided in meters. The National Geodetic Survey's (NGS) GEOID12A 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 used to generate a series of gridded file products, which are tiled into quarter-quads or 5km boxes. The grid file index is provided by the shape file, mi_huron_boxes.shp, and the numbers used to identify files are in the "Box" field of the shape file. The data file naming convention is based on the year, effort, area name, "Box" number and product type. An example file name is "2013_NCMP_MI_Huron_01_BareEarth_1mGrid.tif", where 2013 is the year of data collection, NCMP is the project under which data were collected, MI_Huron is the area of data collection, 01 is the "Box" number, and BareEarth 1mGrid is the product type.

The data were ingested as received from the USACE into the NOAA Digital Coast. Custom processing by the Data Access Viewer may have changed the tiling and naming.

Original contact information:

Contact Org: JALBTCX

Title: Data Production Manager

Phone: 228-252-1121

Email: JALBTCX@usace.army.mil

These data were collected as a part of the NCMP to depict the elevations above and below the water in the Michigan coastal zone.

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These data have been developed from the best available sources. Although efforts have been made to ensure that the data are accurate and reliable, errors and variable conditions originating from physical sources used to develop the data may be reflected in the data supplied. Users must be aware of these conditions and bear responsibility for the appropriate use of the information with respect to possible errors, scale, resolution, rectification, positional accuracy, development methodology, time period, environmental and climatic conditions and other circumstances specific to these data. The user is responsible for understanding the accuracy limitations of the data provided herein. The burden for determining fitness for use lies entirely with the user. The user should refer to the accompanying metadata notes for a description of the data and data development procedures.

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=7380

The data set is dynamically generated based on user-specified parameters.;

These data have been developed from the best available sources. Although efforts have been made to ensure that the data are accurate and reliable, errors and variable conditions originating from physical sources used to develop the data may be reflected in the data supplied. Users must be aware of these conditions and bear responsibility for the appropriate use of the information with respect to possible errors, scale, resolution, rectification, positional accuracy, development methodology, time period, environmental and climatic conditions and other circumstances specific to these data. The user is responsible for understanding the accuracy limitations of the data provided herein. The burden for determining fitness for use lies entirely with the user. The user should refer to the accompanying metadata notes for a description of the data and data development procedures.

These data depict the heights at the time of the survey and are only accurate for that time. Acknowledgement of the Joint Airborne Lidar Bathymetry Technical Center of eXpertise (JALBTCX) would be appreciated in any publications or derived products. The data herein, including but not limited to geographic data, tabular data, analytical data, electronic data structures or files, are provided "as is" without warranty of any kind, either expressed or implied, or statutory, including, but not limited to, the implied warranties or merchantability and fitness for a particular purpose. The entire risk as to the quality and performance of the data is assumed by the user. No guarantee of accuracy is granted, nor is any responsibility for reliance thereon assumed. In no event shall the U.S. Army Corps of Engineers, Mobile District Office, Spatial Data Branch be liable for direct, indirect, incidental, consequential or special damages of any kind, including, but not limited to, loss of anticipated profits or benefits arising out of use of or reliance on the data. The Spatial Data Branch does not accept liability for any damages or misrepresentation caused by inaccuracies in the data or as a result of changes to the data caused by system transfers or other transformations or conversions, nor is there responsibility assumed to maintain the data in any manner or form.

These data are not attributed. | Quantitative Value: N/A | Quantitative Test Explanation: These data are not attributed.

The data positions were obtained using post processed KGPS methods. The horizontal accuracy of CZMIL in the joint topo/bathy mode of operation is +/-1 m, 2 sigma.; Quantitative Value: 1.0 meters, Test that produced the value: +/- 1 m, 2 sigma

The data positions were obtained using post processed KGPS methods. The vertical accuracy of CZMIL in the joint topo/bathy mode of operation is +/-15 cm, 2 sigma. In the hyrodgraphic mode of operation, the vertical accuracy of CZMIl is sqrt[0.3^2 + (0.013 x depth)^2] m, 2 sigma in depths of 0-30 m.; Quantitative Value: 0.10 meters, Test that produced the value: +/- 10 cm RMSE

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

During inspection and QC of the lidar point cloud, flightline to flightline elevation differences met the CZMIL sensor specifications.