2017 ISGS Lidar: Greene, Macoupin, Montgomery Counties, IL

Merrick & Company (Merrick) was contracted by the University of Illinois Urbana-Champaign / Illinois State Geological Survey (ISGS) to provide a lidar validation ground survey, aerial lidar data collection and processing of approximately 2,220.50 square miles for Greene, Macoupin, and Montgomery Counties, IL (IL-3 Counties). LIDAR-derived binary (.las) files ASPRS ver 1.4 format containing classified points of all returns. There are 11 classifications: Unclassified, Ground, Low Veg, Medium Veg, High Veg, Buildings, Low Noise, Water, Ignore Ground, Bridge Decks and High Noise. The files are delivered in section formatted tiles. These files adhere to the National Enhanced Elevation Assessment (NEEA) Quality Level 2 (QL2) standards. The contractual aggregate nominal pulse spacing (ANPS) is less than or equal to 0.71m. The contractual aggregate nominal point density (ANPD) is 2.0 points or greater per square meter.

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.

unknown

The following are the USGS lidar fields in JSON:

{

"ldrinfo" : {

"ldrspec" : "USGS NGP Base Specification v1.2",

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

"ldrmaxnr" : "8",

"ldrnps" : "0.71",

"ldrdens" : "2",

"ldranps" : "0.56",

"ldradens" : "3.2",

"ldrfltht" : "2,150",

"ldrfltsp" : "170",

"ldrscana" : "40",

"ldrscanr" : "62",

"ldrpulsr" : "350",

"ldrpulsd" : "3.5",

"ldrpulsw" : "1.05",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.25",

"ldrswatw" : "1565",

"ldrswato" : "30",

"ldrcrs" : "NAD_1983_2011_StatePlane_Illinois_West_FIPS_1202_Ft_US",

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

},

"ldraccur" : {

"ldrchacc" : "0.1",

"rawnva" : "0.096",

"rawnvan" : "83",

"clsnva" : "0.097",

"clsnvan" : "83",

"clsvva" : "0.178",

"clsvvan" : "61"

},

"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"

},

"lasclass" : {

"clascode" : "4",

"clasitem" : "Medium Veg"

},

"lasclass" : {

"clascode" : "5",

"clasitem" : "High Veg"

},

"lasclass" : {

"clascode" : "6",

"clasitem" : "Building"

},

"lasclass" : {

"clascode" : "7",

"clasitem" : "Low point (noise)"

},

"lasclass" : {

"clascode" : "9",

"clasitem" : "Water"

},

"lasclass" : {

"clascode" : "10",

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

},

"lasclass" : {

"clascode" : "17",

"clasitem" : "Bridge Decks"

},

"lasclass" : {

"clascode" : "18",

"clasitem" : "High Noise"

}

}}

ASPRS ver 1.4 format:1 = Unclassified2 = Ground3 = Low Veg4 = Medium Veg5 = High Veg6 = Building7 = Low Noise9 = Water10 = Ignore Ground17 = Bridge18 = High Noise

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 Vista Version 6.1 (Build 7601) Service Pack 1; ESRI ArcCatalog 9.3.1.4095

This data set was produced to meet ASPRS Positional Accuracy Standards for Digital Geospatial Data (2014) for a 22.5 (cm) RMSEx / RMSEy Horizontal Accuracy Class which equates to Positional Horizontal Accuracy = +/- 55.1 cm at a 95% confidence level.

This data set was tested to meet ASPRS Positional Accuracy Standard for Digital Geospatial Data (2014) for a 10.0-cm RMSEz Vertical Accuracy Class. Actual NVA accuracy was found to be RMSEz = 4.914 cm, equating to +/- 9.632 cm at the 95% confidence level. Actual VVA accuracy was found to be +/- 17.8 cm at the 95th percentile. These results are verified against a TIN. Classified Non-Vegetated Vertical Accuracy (NVA) tested 0.097 meters vertical accuracy at the 95 percent confidence level. Eighty-three (83) NVA points were used and validated against the DEM. Classified Vegetated Vertical Accuracy (VVA) tested 0.182 meters vertical accuracy at the 95th percentile. Sixty-one (61) VVA points were used and validated against the DEM.

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.