2020 ISGS Lidar: 8 County, IL

Product: Processed, classified lidar point cloud data tiles in LAS 1.4 format.

Geographic Extent: The data covers approximately 3985 square miles in the Wabash and Embarras Rivers Basin in east central Illinois.

IL_8County_B1 (Work Unit 1922332):

The data covers 2576 square miles in the following counties: Clark, Coles, Cumberland, Douglas, Edgar

Collected by Merrick & Company, Inc.

IL_8County_B2 (Work Unit 193826):

The data covers 1409 square miles in the following counties: Crawford, Jasper, Lawrence

Collected by Woolpert

Dataset Description of the Original Data: The 2020 data acquisition of 8 Counties in the Wabash and Embarras Basin lidar project called for the planning, acquisition, processing, and production of derivative products of QL2+ lidar data to be collected at a nominal pulse spacing (NPS) of 0.5 meters. Project specifications were based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 2.1. The data was developed based on a horizontal datum/projection of NAD83 (2011) State Plane Illinois East Zone Survey Feet, and a vertical datum of NAVD88 (GEOID12B) US Survey Feet. Lidar data was delivered as processed LAS 1.4 files formatted to individual 2,000-foot x 2,000-foot tiles. The contractual aggregate nominal pulse spacing (ANPS) is less than or equal to 0.5m. The contractual aggregate nominal point density (ANPD) is 4.0 points or greater per square meter. Classifications include: Unclassified, Ground, Automated Low Veg [0.5-5 feet], Automated Medium Veg [5-20 feet], Automated High Veg [>20 feet], Automated Buildings, Low Noise, Water, Bridge Decks, High Noise and Ignore Ground (breakline proximity). Model key points are bit-flagged and created from ground (class = 2) points using a five foot horizontal and a 0.2 foot vertical variance.

Ground Conditions: Lidar was collected from March 30, 2020 through May 4, 2020 while no snow was on the ground and rivers were at or below normal levels. In order to post process the lidar data to meet task order specifications and meet ASPRS vertical accuracy guidelines,

This metadata record supports the data entry in the NOAA Digital Coast Data Access Viewer (DAV). For this data set, the DAV is leveraging the Entwine Point Tiles (EPT) hosted by USGS on Amazon Web Services.

The purpose of this project was to obtain Lidar data for the Illinois Height Modernization Program.

The following are the USGS lidar fields in JSON:

{

"ldrinfo" : {

"ldrspec" : "USGS-NGP Base Lidar Specification v2.1",

"ldrsens" : "Optech Galaxy Prime Airborne Laser Terrain Mappers (ALTM) 5060380",

"ldrmaxnr" : "8",

"ldrnps" : "0.5",

"ldrdens" : "4",

"ldranps" : "0.5",

"ldradens" : "4",

"ldrfltht" : "1750",

"ldrfltsp" : "170",

"ldrscana" : "42",

"ldrscanr" : "95",

"ldrpulsr" : "700",

"ldrpulsd" : "3.5",

"ldrpulsw" : "0.875",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.25",

"ldrswatw" : "1344",

"ldrswato" : "20",

"ldrgeoid" : "National Geodetic Survey (NGS) Geoid12B"

},

"ldraccur" : {

"ldrchacc" : "0",

"rawnva" : "0",

"rawnvan" : "0"

},

"lasinfo" : {

"lasver" : "1.4",

"lasprf" : "6",

"laswheld" : "Withheld (ignore) points were identified in these files using the standard LAS Withheld bit.",

"lasolap" : "Swath "overage" points were identified in these files by a separate bit flag.",

"lasintr" : "12-bit",

"lasclass" : {

"clascode" : "1",

"clasitem" : "Undetermined/Unclassifed"

},

"lasclass" : {

"clascode" : "2",

"clasitem" : "Ground"

},

"lasclass" : {

"clascode" : "3",

"clasitem" : "Low Veg (Automated)"

},

"lasclass" : {

"clascode" : "4",

"clasitem" : "Medium Veg (Automated)"

},

"lasclass" : {

"clascode" : "5",

"clasitem" : "High Veg (Automated)"

},

"lasclass" : {

"clascode" : "6",

"clasitem" : "Building (Automated)"

},

"lasclass" : {

"clascode" : "7",

"clasitem" : "Low point (noise)"

},

"lasclass" : {

"clascode" : "9",

"clasitem" : "Water"

},

"lasclass" : {

"clascode" : "17",

"clasitem" : "Bridge Decks"

},

"lasclass" : {

"clascode" : "18",

"clasitem" : "High Noise"

},

"lasclass" : {

"clascode" : "20",

"clasitem" : "Ignore ground (near a breakline)"

}

}}

ASPRS ver 1.4 format:1 = Unclassified2 = Ground3 = Low Veg [0.5-5 feet]4 = Medium Veg [5-20 feet]5 = High Veg [>20 feet]6 = Automated Building7 = Low Noise9 = Water17 = Bridge18 = High Noise20 = Ignore Ground (breakline proximity)Model key points are bit-flagged and created from ground (class = 2) points using a 5 foot horizontal and a 0.2 foot vertical variance.

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

Data is available online for bulk and custom downloads.

None

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.

Microsoft Windows 7 Professional Service Pack 1; ESRI ArcCatalog 10.7.1

For IL_8County_B2 (Work Unit 193826) which includes Crawford, Jasper, and Lawrence counties, the data set was produced to meet ASPRSPositional Accuracy Standards for Digital Geospatial Data (2014) for a 17.6 cm RMSEx / RMSEy Horizontal Accuracy Class which equates to Positional Horizontal Accuracy = +/- 43.2 cm at a 95% confidence level.

No information about the horizontal accuracy was provided for IL_8County_B1 (Work Unit 192232) which includes Clark, Coles, Cumberland, Douglas, and Edgar counties.

This data set was produced to meet ASPRS Positional Accuracy Standard for Digital Geospatial Data (2014) for a 10-cm RMSEz Vertical Accuracy Class.

USGS Determined Vertical Accuracy:

Tested NVA RMSEz = 4.12 cm

Tested NVA Accuracy z at 95% confidence interval (RMSEz * 1.96) = 8.09 cm

Tested 95th percentile value for VVA is : 12.61 cm

For more information see the USGS project report and the lidar reports. The links to these reports are provided in the URL section of this metadata record.

The dataset was captured, attributed, and reviewed to ensure completeness and accuracy of at least 95%.

The dataset was captured, attributed, and reviewed to ensure completeness and accuracy of at least 95%.

Data is backed up to cloud storage.

The NOAA Office for Coastal Management (OCM) ingested references to the USGS Entwine Point Tiles (EPT) hosted on Amazon Web Services (AWS) into the Digital Coast Data Access Viewer (DAV). The DAV accesses the point cloud as it resides on AWS under the usgs-lidar-public-container.