2007 ARRA Lidar: Lake County, IL

The Classified Point Cloud LAS files consist of 5 different classifications: Unclassified, Ground, Noise, Water and Ignored Ground. Merrick used the Leica ALS50 sensor. Merrick & Company flew a mapping mission in April/May 2007 to capture aerial photography over 539 square miles of Lake County, Illinois.

Questions pertaining to this dataset can be forward to the Lake County Department of Information and Technology/GIS Mapping Division in Waukegan, IL at maps@lakecountyil.gov (or KCaldwell@co.lake.il.us)

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A report for this project is available at:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/4794/supplemental/il2007_arra_lake_co_m4794_surveyreport.pdf

A footprint of this data set may be viewed in Google Earth at:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/4794/supplemental/il2007_arra_lake_co_m4794.kmz

LAS 1.2 format (classes 1,2,9,10)

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Any conclusions drawn from the analysis of this information are not the responsibility of Merrick & Co, USGS, NOAA, the Office for Coastal Management or its partners.

This data can be obtained on-line at the following URL:

https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=4794

The data set is dynamically generated based on user-specified parameters.;

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Users should be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions. Users should not use this data for critical applications without a full awareness of its limitations. These data depict the heights at the time of the survey and are only accurate for that time.

See report

The ortho imagery horizontal positional accuracy and the assurance of that accuracy depend, in part, on the accuracy of the data inputs to the rectification process. These inputs consist of the digital terrain model (DTM), fully digital analytic aerotriangulation (FDAAT) control and methods, the photo source camera calibration, scanner calibration, and aerial photographs. The orthoimagery output from these inputs meet National Map Accuracy Standards (NMAS). Aerial cameras have current certification from the USGS, National Mapping Division, Optical Science Laboratory. Test calibration scans are performed on all source photography scanners.; Quantitative Value: 0.068 meters, Test that produced the value: The horizontal positional accuracy value is derived from a standard aerotriangulation process known as a simultaneous bundle adjustment. Coordinates of ground points are derived from the measured coordinates of image points using mathematical functions. These corrections are made to points distributed over a large area, known as a block. The resulting solution is obtained simultaneously for all points to maintain consistency of all the stereo-models within the block. 0.236 feet RMSE X; 0.212 feet RMSE Y, averaging to 0.224 ft overall.

NSSDA accuracy of 0.59 feet exceeds Fundamental Vertical Accuracy (FVA) requirement of 0.6 feet; Quantitative Value: 0.088 meters, Test that produced the value: RMSE(z) in meters

The dataset was reviewed to ensure complete coverage of the project area.

Calibrations of the LIDAR flightline data are performed; this process is known as boresighting. The flightlines are compared to evaluate both their relative and absolute accuracies.