2017 ISGS Lidar: Cass County, IL

Create custom data files by choosing data area, product type, map projection, file format, datum, etc. A new metadata will be produced to reflect your request using this record as a base. Change to an orthometric vertical datum is one of the many options.

Bulk download of data files in LAZ format, geographic NAD83 (2011) coordinates and elevations in NAVD88 (GEOID18) meters.

The Data Access Viewer (DAV) allows a user to search for and download elevation, imagery, and land cover data for the coastal U.S. and its territories. The data, hosted by the NOAA Office for Coastal Management, can be customized and requested for free download through a checkout interface. An email provides a link to the customized data, while the original data set is available through a link within the viewer.

Link to the reports, breaklines, metadata, and spatial metadata.

Entwine Point Tile (EPT) is a simple and flexible octree-based storage format for point cloud data. The data is organized in such a way that the data can be reasonably streamed over the internet, pulling only the points you need. EPT files can be queried to return a subset of the points that give you a representation of the area. As you zoom further in, you are requesting higher and higher densities. A dataset in EPT will contain a lot of files, however, the ept.json file describes all the rest. The EPT file can be used in Potree and QGIS to view the point cloud.

Link to view the point cloud, using the Entwine Point Tile (EPT) format, in the 3D Potree viewer.

Link to the USGS Project Report that provides information about the project, vertical accuracy results, and the point classes and sensors used.

Acquisition was completed in March and November 2017 using a single engine Cessna 206 equipped with an Optech Galaxy. Flight plan parameters were based on 6060 feet AGL, 45 deg FOV, 250,400 pulse rate, 20% sidelap, 0.67 meter NPS. Crews based out of Jacksonville Muncipal Airport, Illinois. Due to it's location near the Illinois River, the Northwest portion of the County had large amounts of backwater with associated ponds, sloughs and swales.

All flights have calibration lines flown at beginning and end of flight perpendicular to lines captured during that mission. Base stations were continuously running during missions and placed so flight baseline never exceeds 30 miles.

GPS-IMU captured during flight was processed using Waypoint's Inertial Explorer software. The bare-earth Lidar data was processed to USGS (NGP) Base Lidar Specifications V1.2 using the Terrasolid software suite. LiDAR point was initally processed with macros to locate bare earth ground, buildings and three classes of vegetation but was manually reviewed by experienced technicians in TerraScan or LP360 software for proper point classifciations in LAS tile format. Derivative product formats such as *.DAT, *.DGN, ESRI raster grid and TIN formats were produced using ESRI, Microstation and other software formats.

Hydro features were collected on streams and rivers 100~ feet or wider and on lakes 2~ acres or larger. These lines were hydro flattened into the Lidar data and delivered in ESRI geodatabase file format. Please NOTE: A lone reflight occurred in late November, 8 months after the original collection that had water levels that were significantly lower, approximately 2.5 feet, causing some visual elevation mismatches between the original dataset and the reflight. These small areas were desiginated as "Unclassified" and were coded as Class I to reflect this anomaly.

The Office for Coastal Management (OCM) downloaded 2954 laz files from the USGS rockyweb site for the Cass County IL dataset. The data were in IL State Plane West, NAD83 2011, US survey feet coordinates and NAVD88 (Geoid12B) elevations in feet. The points were classified as 1- Unclassified, 2 - Ground, 3 - Low Vegetation, 4 - Medium Vegetation, 5 - High Vegetation, 6 - Buildings, 9 - Water, 10 - Ignored Ground, 17 - Bridge Deck. All points were processed to the NOAA Digital Coast Data Access Viewer (DAV) for data provisioning. The classes available on DAV are: 1,2,3,4,5,6,9,10,17.

OCM performed the following processing on the data for Digital Coast storage and provisioning purposes:

1. Internal OCM scripts were run to check the number of points by classification and by flight ID and the gps, elevation, and intensity ranges.

2. Internal OCM scripts were run on the laz files to:

a. Convert from orthometric (NAVD88) elevations in feet to NAD83 (2011) ellipsoid elevations in meters using the Geoid12B model

b. Convert the laz files from IL State Plane West, NAD83 2011, US survey feet coordinates to geographic coordinates

c. Assign the geokeys, sort the data by gps time and zip the data to database