2008 US Army Corps of Engineers (USACE) National Coastal Mapping Program Topobathy Lidar: Lake Michigan

Create custom data files by choosing data area, product type, map projection, file format, datum, etc.

Simple download of data files.

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.

Partial upload of Positional Accuracy fields only.

Partial upload to move data access links to Distribution Info.

These data were collected using the CHARTS system. It is owned by the Naval Oceanographic Office and operated through contract.

The system collects topographic lidar data at 9kHz, bathymetric lidar data at 1kHz and RGB imagery at 1Hz. 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 410 equipment. All raw data streams are transferred to the office for downloading and processing in

SHOALS GCS 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. PFM_ABE's chartsLAS module then converts all valid data from ellipsoid to orthometric heights based on

the NGS' GEOID03 model and exports data as a series of first return topography (TF), last return topography (TL) and bathymetry (H)

ASCII files. The bathymetry files contain all of the returns from the bathymetric sensor which include returns both above and below

the water.

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 3-D position data were sub-divided into a series of ASCII file

products, with each covering approximately 5 kilometers of shoreline. The file index was provided by the shape file,

"mi_michigan_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, project, area name, "Box" number and product type (topographic or bathymetric). An example file

name is "2008_NCMP_MI_Michigan_07_ASCII", where 2008 is the year of data collection, NCMP is the project under which data were

collected, MI_Michigan is the area of data collection, 07 is the "Box" number and ASCII is the product type. The ASCII columns

are Longitude, Latitude, UTM Zone, Easting, Northing, Elevation (orthometric), Elevation (ellipsoid), Date, Time, and Intensity.

The NOAA Office for Coastal Management (OCM) received topo and hydro files in ASCII format. The files contained

LiDAR elevation and intensity measurements. The points were classed as 'never classified.' The data were provided in Geographic

coordinates and ellipsoidal heights and in orthometric heights. OCM performed the following processing to the ellipsoidal height

data to make it available within the Digital Coast:

1. LASEdit was used to convert the ASCII formatted files to las format.

2. The hydro points classification was changed from 'never classified' to class 11, 'bathymetry'. The topo points classification remains

as class 0, 'never classified'.

3. The LAS data were sorted by latitude and the headers were updated.