2012 USACE Great Lakes Topobathy Lidar: Lake Michigan (Wisconsin and Michigan)

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This graphic shows the coverage of the 2012 USACE Lake Michigan lidar in Wisconsin and on the upper peninsula of Michigan.

Date that the source FGDC record was last modified.

Converted from FGDC Content Standards for Digital Geospatial Metadata (version FGDC-STD-001-1998) using 'fgdc_to_inport_xml.pl' script. Contact Tyler Christensen (NOS) for details.

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These data were collected using the CZMIL system. It is owned and operated by the U.S. Army Corps of Engineers (USACE). The system collects lidar data at 20 kHz and RGB imagery at 2 Hz. 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 510 equipment. All raw data streams are transferred to the office for downloading and processing in CZMILs Hydro Fusion 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. NOAA's VDatum software then converts all valid data from ellipsoid to orthometric heights based on the NGS' GEOID12A model and exports valid lidar data as a series of unclassified LAS files.

LAS files are imported into GeoCue V2012.1.27.7, which is a geospatial workflow production and management software tool employed by JALBTCX to perform and monitor production of data products. Upon import into GeoCue, A customized classification macro, built upon the TerraScan V13 module within Microstation V8i, classifies valid topographic data as ground points (2), valid bathymetric data as bathy (29), and unclassified points (1). Upon completion the macro, the classification results undergo quality control and any misclassified points are manually edited. In areas of dense vegetation the bare earth ground points might be incorrectly classified due to the inability of the laser to penetrate the canopy and reach the bare ground. In these areas, JALBTCX defaults to the algorithms ground surface instead of manually reclassifying those points. The final classification results are comprised of individual lidar points with classifications of ground (2) or unclassified (1). They are partitioned into a series of 5km or quarter quad delivery boxes, one Classified LAS file per box. The format of the file is LAS version 1.2. Data are classified as 1 (valid non-ground topographic data), 2 (valid ground topographic data), 29 (valid bathymetric data).

The NOAA Office for Coastal Management (OCM) received the topographic/bathymetric files in LAS format from USACE. The files contained lidar easting, northing, elevation, intensity, return number, etc. The data was received in Geographic Coordinates (decimal degrees). The vertical coordinates were referenced to NAVD88 in meters using the Geoid12a model. OCM performed the following processing for data storage and Digital Coast provisioning purposes:

1. Two separate projects from 2012 were combined for one OCM mission. Lake Michigan data for the upper peninsula was delivered with lower Michigan data although that region had previously been added to the Digital Coast, there OCM combined the portion which had not been added to the Wisconsin portion of the 2012 Lake Michigan delivered data. The result project is the western shore of Lake Michigan from near Monitowoc in Wisconsin to Escanaba in Michigan (600+ kilometers of shoreline).

2. Class 29 points (bathymetry) were reclassified to Class 11 (bathymetry) to fit OCM DAV class scheme.