Data Management Plan (Deprecated)

The Light Detection and Ranging (LiDAR) dataset is a survey of the NRCS Christian Co Ill LiDAR Survey and encompasses 715 square miles. The LiDAR point cloud was flown at a nominal post spacing of 0.5 meters for un-obscured areas. The LiDAR data and derivative products produced are in compliance with the U.S. Geological Survey National Geospatial Program Guidelines and Base Specifications, Version 1.0 The flight lines were acquired by Digital Aerial Solutions, LLC. between Dec. 2014 and March 2015. Derivative products from the aerial acquisition include: Raw point cloud data in LAS v1.2, classified point cloud data in LAS v1.2, bare earth surface tiles (raster DEM GeoTIFF format), bare earth surface DEMs mosaic (raster ESRI float GRID format), Intensity images (8 bit tif format with world files), control points, project report, and FGDC compliant XML metadata.

Lineage Statement:
This data was collected by Digital Aerial Solutions for the Natural Resources Conservation Service (NRCS) and the U.S. Geological Survey (USGS). The data were made available for download by USGS. The NOAA Office for Coastal Management (OCM) downloaded the data to make the data available for custom download from the NOAA OCM Digital Coast Data Access Viewer (DAV) and for bulk download from AWS S3.

Process Steps:

• 2015-03-31 00:00:00 - The ABGPS, inertial measurement unit (IMU), and raw scans are collected during the LiDAR aerial survey. The ABGPS monitors the xyz position of the sensor and the IMU monitors the orientation. During the aerial survey, laser pulses reflected from features on the ground surface are detected by the receiver optics and collected by the data logger. GPS locations are based on data collected by receivers on the aircraft and base stations on the ground. The ground base stations are placed no more than 40 km radius from the flight survey area.
• 2015-04-28 00:00:00 - The ABGPS, IMU, and raw scans are integrated using proprietary software developed by Leica Geosystems called IPAS Pro (Version 1.35). These LiDAR data are then output to a ASPRS Version 1.2 LAS binary format using Leica Geosystems ALSPP post-processing software (Release 2.75 Build #25 ) The LAS version 1.2 file format can be easily transferred from one file format to another. It is a binary file format that maintains information specific to the LiDAR data (return number, intensity value, xyz, etc.). The header file for each dataset is complete as defined by the LAS 1.0 specification.
• 2014-05-15 00:00:00 - The unedited data are classified to facilitate the application of the appropriate feature extraction filters. Combinations of proprietary filters are applied as appropriate for the production of bare earth digital elevation models (DEMs). Interactive editing methods are applied to those areas where it is inappropriate or impossible to use the feature extraction filters, based upon the design criteria and/or limitations of the relevant filters. These same feature extraction filters are used to produce elevation height surfaces. The data was classified as follows: Class 1 =Processed, but unclassified Class 2 = Bare-earth ground Class 3 = Low Vegetation is 0-5 feet Class 4 = Medium Vegetation is 5-20 feet Class 5 = High Vegetation is 20 feet or more Class 6 = Buildings, bridges, other manmade structures Class 7 = Noise (low or high, manually identified, if needed Class 9 = Water Class 10 Ignored Ground (Breakline Proximity) Class 14 = Ground Overlap Class 15 = Defualt Overlap Class 17 = Bridge Decks
• 2015-06-20 00:00:00 - Filtered and edited data are subjected to rigorous QA/QC, A series of quantitative and visual procedures are employed to validate the accuracy and consistency of the filtered and edited data. Ground control is established by DAS and GPS-derived ground control points (GCPs) in various areas of dominant and prescribed land cover. These points are coded according to land cover, surface material, and ground control suitability. A suitable number of points are selected for calculation of a statistically significant accuracy assessment, as per the requirements of the National Standard for Spatial Data Accuracy. A spatial proximity analysis is used to select edited LiDAR data points within a specified distance of the relevant GCPs. A search radius decision rule is applied with consideration of terrain complexity, cumulative error, and adequate sample size. Accuracy validation and evaluation is accomplished using proprietary software to apply relevant statistical routines for calculation of Root Mean Square Error (RMSE) and the National Standard for Spatial Data Accuracy (NSSDA), according to Federal Geographic Data Committee (FGDC) specifications.
• 2024-06-05 00:00:00 - The Office for Coastal Management (OCM) downloaded 775 laz files from the USGS rockyweb site for the NRCS_Christian_County_IL dataset. The data were in IL State Plane West, NAD83 HARN, US survey feet coordinates and NAVD88 (Geoid12B) elevations in feet. The points were classified as 1- Unclassified, 2 - Ground, 3 - Low Vegetation (0 - 5 ft), 4 - Medium Vegetation (5 - 20 ft), 5 - High Vegetation (20 ft or more), 6 - Buildings, 7 - Low Noise, 9 - Water, 10 - Ignored Ground, 14 - Overlap Ground, 15 - Overlap Unclassified, 17 - Bridge Deck. The class 14 points were reclassified to 22 and the class 15 points were reclassified to 21. All points were processed to the NOAA Digital Coast Data Access Viewer (DAV) for data provisioning. The classes available on DAV are: 1,2,3,4,5,6,7,9,10,17,21,22. 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. Re-classify the Class 14 points to 22 (Overlap Ground) and the Class 15 points to 21 (Overlap Unclassified) b. Convert from orthometric (NAVD88) elevations in feet to NAD83 (2011) ellipsoid elevations in meters using the Geoid12B model c. Convert the laz files from IL State Plane West, NAD83 HARN, US survey feet coordinates to geographic coordinates d. Assign the geokeys, sort the data by gps time and zip the data to database

Data is available online for bulk and custom downloads.

Data is backed up to cloud storage.