2008 USGS Lidar: Twelve County, Illinois (Grundy, Kane, McHenry only)

This LiDAR data is within Illinois Department of Transportation districts 1 and 3 covering Grundy, Kane and McHenry counties. The data is updated from its original format to LAS version 1.2. The LiDAR data was collected in April 2008. Task Order Number: 3. Data was acquired by Quantum Spatial as project 1080208 with an Optech ALTM 3100 sensor equipped with an inertial measuring unit (IMU) and GPS receiver. The acquisition was to produce bare earth ASCII, LAS data and 2 foot contour Shapefiles. Only the counties of Grundy, McHenry and Kane were included in the Digital Coast project, as the other nine counties are not directly related to NOAA OCM tools and internal products.

The LiDAR data is updated to be more compatible within the guidelines of the National Digital Elevation Program. (NDEP)

The Grundy County, Illinois LiDAR Acquisition project was to provide high accuracy bare-earth processed LiDAR data and produce 2 foot contours for the county, approximately 430 square miles. The Kane County, Illinois LiDAR Acquisition project was to provide high accuracy bare-earth processed LiDAR data and produce 2 foot contours for Kane county, approximately 525 square miles. The McHenry County, Illinois LiDAR Acquisition project was to provide high accuracy bare-earth processed LiDAR data and produce 2 foot contours for the county, approximately 610 square miles.

The project consisted of acquisition, post-processing, classification of LiDAR data and contour generation. The data was collected at nominal horizontal spacing of 1.2 meters based on the Illinois Stat Plane Coordinate System, East Zone 1201, related to the North American Datum of 1983 (NSRS2007). Vertical accuracy was to achieve a tested accuracy to support 2 foot mapping relative to the North American Vertical Datum of 1988. Original data delivered in reference to NAVD88 in ft.

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Reports for this project are available at:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/5020/supplemental/il2008_usgs_12county_grundy_kane_mchenry_m5020_lidarreport.pdf

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

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/5020/supplemental/il2008_usgs_12county_grundy_kane_mchenry_m5020.kmz

LAS 1.2 format (classes 1,2,7,8,9,10)

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Any conclusions drawn from the analysis of this information are not the responsibility of Woolpert, 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=5020

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.

The vertical accuracy assessment is conducted by comparing ground survey check point z values to processed LiDAR data z values by horizontal proximity. Differences in z values are calculated to express an RMSEz value.

Vertical accuracy statement is based on the area of moderate to flat terrain. The accuracy of the LiDAR data as tested met the vertical accuracy of 1.19 foot or less standards, however, derived products may be less accurate in areas of dense vegetation due to a lesser number of points defining the bare-earth in these areas.

All these data products were acquired at 1700 meters above mean terrain (AMT) and have a horizontal accuracy of 0.31 meters, with a nominal point spacing of 1.2 meters.

This data set was acquired, processed and checked for vertical accuracy in 2008. Vertical accuracy of the LiDAR data was assessed along guidelines of the time established for two foot contour intervals by Federal Emergency Management Agency and by methods of the American Society for Photogrammetry and Remote Sensing and the National Digital Elevation Program.

Vertical Accuracy Assessment values were established by a comparison of ground survey points to a Triangulated Irregular Network (TIN) of LiDAR points.

The Fundamental Vertical Accuracy (FVA) of the TIN is to achieve 1.19ft at a 95% confidence level in the "Open Terrain" land cover category according to ASPRS Guidelines to produce contours of two foot intervals.

The Consolidated Vertical Accuracy (CVA) of the TIN is to achieve 1.19ft at the 95th percentile according to ASPRS guidelines for points in all land cover categories. In 2009 the CVA value stated here was established using all ground survey points that were available. One hundred sixty (160) points included in the CVA evaluation were not indicated by a ground cover category. Therefore the quantity of points in the five ground cover categories do not equal the total used to establish the CVA.

Supplemental Vertical Accuracy (SVA) target value of the TIN is 1.19 ft at the 95th percentile as derived by the ASPRS guidelines in each land cover category evaluated. Land Cover categories are Open Terrain, Short Grass, Tall Grass, Brush, and Forest.

; Quantitative Value: 0.055 meters, Test that produced the value: Tested RMSE of the Classified Points = 5.5 cm (0.18 ft) in Open Terrain as tested against the TIN.

; Quantitative Value: 0.107 meters, Test that produced the value: Tested FVA of 10.7 cm (0.35 ft) at the 95% confidence level on 21 points in Open Terrain as tested against the TIN.

; Quantitative Value: 0.122 meters, Test that produced the value: Tested 12.2 cm (0.40 ft) SVA at the 95th Percentile on 21 points in Short Grass category against the TIN.

; Quantitative Value: 0.125 meters, Test that produced the value: Tested 12.5 cm (0.41 ft) SVA at the 95th Percentile on 22 points in Tall Grass category against the TIN.

; Quantitative Value: 0.192 meters, Test that produced the value: Tested 19.2 cm (0.63 ft) SVA at the 95th Percentile on 20 points in Brush category against the TIN.

; Quantitative Value: 0.192 meters, Test that produced the value: Tested 19.2 cm (0.63 ft) SVA at the 95th Percentile on 19 points in Forested category against the TIN.

; Quantitative Value: 0.094 meters, Test that produced the value: Tested 9.4 cm (0.31 ft) SVA at the 95th Percentile on 21 points in Open Terrain category against the TIN.

; Quantitative Value: 0.174 meters, Test that produced the value: Tested 17.4 cm (0.57 ft) CVA at the 95th Percentile on 103 points in all ground categories against the TIN.

Complete

Data covers the area specified for this project.