Data Management Plan (Deprecated)

This data set is an LAZ (compressed LAS) format file containing LIDAR point cloud data. This data set is an LAZ (compressed LAS) format file containing LIDAR point cloud data. The data contained in these files contain hydrographic and topographic data collected by the CHARTS system along the Lake Michigan coast of Illinois from September 17 - September 26, 2008. These files contain topographic and bathymetric lidar data collected by the Compact Hydrographic Airborne Rapid Total Survey (CHARTS) system. CHARTS integrates topographic and bathymetric lidar sensors, a digital camera, and a hyperspectral scanner on a single remote sensing platform for use in coastal mapping and charting activities. Data coverage generally extends along the coastline from the waterline inland 500 meters (topography) and offshore 1,000 meters or to laser extinction (bathymetry). The topographic lidar sensor has a pulse repetition rate of 9 kHz at 1064 nm (near-infrared wavelength). The bathymetric lidar sensor has a pulse repetition rate of 1 kHz at 532 nm (green wavelength). Native lidar data is 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 imported into GIS software for visualization and further analysis. The data were collected and provided in decimal degrees of latitude and longitude, referenced to the North American Datum of 1983 (NAD83). Vertical positions were referenced to the NAD83 ellipsoid and provided in meters. 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). For data storage and provisioning purposes, the NOAA Office for Coastal Management converted the data from NAVD88 heights to ellipsoid heights using GEOID03.

Additionally, the data were unclassified when received; NOAA OCM classified the topo laser data as 1 and the bathy laser data as 11. Upland bathy laser points were reclassed to unclassified points (1). Classifications for ground (2), vegetation (3,4,5), and buildings (6) were subsequently done using only the unclassified (1) points.

Lineage Statement:
The US Army Corps of Engineers flew the SHOALS sensor along the shore of Lake Michigan and produced an ASCII data set with the green (bathy) and infra-red (topo) data separated. NOAA converted the data to LAS format, assigning different classes based on the laser. The data was further converted to ellipsoid heights as the standard for the Data Access Viewer. The topo data was classified for ground, buildings, and vegetation using automated tools.

Process Steps:

• 2009-01-01 00:00:00 - 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 9 kHz, bathymetric lidar data at 1 kHz 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.
• 2011-02-01 00:00:00 - The NOAA Office for Coastal Management (OCM) received the data as unclassified files in ASCII format. The files contained LiDAR intensity and elevation measurements. OCM performed the following processing on the data for data storage and Digital Coast provisioning: 1. The data were converted from ASCII to las format. 2. The data were classified as 1 for the topo data (no bare earth) using the topo last (TL) elevation and 11 for the hydro data. 3. The data were converted from NAVD88 heights to ellipsoid heights using Geoid03. 4. The LAS header fields were sorted by latitude and updated. (Citation: ASCII lidar point cloud)
• 2014-01-09 00:00:00 - Times had originally been stored as POSIX seconds when converted to LAS. This was switched to adjusted GPS time (GPS seconds - 1e9) to conform to the LAS 1.2 standard.
• 2022-07-26 00:00:00 - The point cloud was classified using LAStools. Class 11 points (representing returns from the green laser) were ignored for the classification. Steps included: 1) ground classification using lasground_new 2) height above ground determination with lasheight 3) vegetation and building classification with lasclassify -step 4 Data were converted to utm before classification and back to geographic after classification. No manual corrections of classification artifacts or errors was done. Some issues were noted, particularly with the vegetation and building classifications. Those classes should be used with caution.

This data can be obtained on-line at the following URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=563;