2015 ILHMP Lidar DEM: Ford, Iroquois & Livingston Counties, IL

Original Dataset Description: This project involved fixed wing aerial LIDAR data collected at a contracted point spacing of 0.70 meters for the Illinois Counties of Ford, Iroquois and Livingston totaling approximately 2,740 square miles.

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 GeoTIFF files hosted by USGS on Amazon Web Services.

To acquire detailed surface elevation data for the Illinois Height Modernization Program (ILHMP) which is managed by the Illinois State Geological Survey (ISGS).

LiDAR

The following are the USGS lidar fields in JSON:

{

"ldrinfo" : {

"ldrsens" : "Leica ALS70-HP",

"ldrspec" : "1.0",

"ldrmaxnr" : "4",

"ldrnps" : "0.67",

"ldrdens" : "2.20",

"ldranps" : "0.67",

"ldradens" : "2.20",

"ldrfltht" : "1450",

"ldrfltsp" : "150",

"ldrscana" : "40",

"ldrscanr" : "53.4",

"ldrpulsr" : "375",

"ldrpulsd" : "10",

"ldrpulsw" : "3",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.22",

"ldrswatw" : "1055",

"ldrswato" : "20",

"ldrcrs" : "NAD_1983_2011_Stateplane_Illinois_East_FIPS_1201_Ft_US",

"ldrgeoid" : "National Geodetic Survey (NGS) Geoid12A. The GEOID12A model is intended to transform between NAD 83 (2011/PA11/MA11) and the respective vertical datums for the different regions, including NAVD88, GUVD04, ASVD02, NMVD03, PRVD02 and VIVD09."

},

"ldraccur" : {

"ldrchacc" : "0.328 feet RMSEz",

"rawnva" : "0.256 feet RMSEz, 0.502 feet 95% ACCz Confidence Level bare-earth, short grass",

"rawnvan" : "215",

"clsnva" : "0.217 feet RMSEz, 0.425 feet 95% ACCz Confidence Level bare-earth, short grass",

"clsnvan" : "215",

"clsvva" : "0.956 feet 95th Percentile, Tall Grass, Trees/Forested, Brush",

"clsvvan" : "292"

},

"lasinfo" : {

"lasver" : "1.2",

"lasolap" : "17",

"laswheld" : "11",

"lasintr" : "11",

"lasprf" : "3",

"lasclass" : {

"clascode" : "1",

"clasitem" : "Unclassified"

},

"lasclass" : {

"clascode" : "2",

"clasitem" : "Ground"

},

"lasclass" : {

"clascode" : "3",

"clasitem" : "Low vegetation"

},

"lasclass" : {

"clascode" : "4",

"clasitem" : "Medium vegetation"

},

"lasclass" : {

"clascode" : "5",

"clasitem" : "High vegetation"

},

"lasclass" : {

"clascode" : "6",

"clasitem" : "All structures except bridges"

},

"lasclass" : {

"clascode" : "7",

"clasitem" : "All noise"

},

"lasclass" : {

"clascode" : "8",

"clasitem" : "Keypoint"

},

"lasclass" : {

"clascode" : "9",

"clasitem" : "Water"

},

"lasclass" : {

"clascode" : "10",

"clasitem" : "Proximity to hydro breakline"

},

"lasclass" : {

"clascode" : "14",

"clasitem" : "bridge decks"

},

"lasclass" : {

"clascode" : "17",

"clasitem" : "Overlap unclassified"

},

"lasclass" : {

"clascode" : "18",

"clasitem" : "Overlap ground"

},

"lasclass" : {

"clascode" : "19",

"clasitem" : "Overlap Low vegetation"

},

"lasclass" : {

"clascode" : "20",

"clasitem" : "Overlap Medium vegetation"

},

"lasclass" : {

"clascode" : "21",

"clasitem" : "Overlap High vegetation"

},

"lasclass" : {

"clascode" : "22",

"clasitem" : "Overlap All structures except bridges"

},

"lasclass" : {

"clascode" : "23",

"clasitem" : "Overlap All noise"

},

"lasclass" : {

"clascode" : "24",

"clasitem" : "Overlap Keypoint"

},

"lasclass" : {

"clascode" : "25",

"clasitem" : "Overlap Water"

},

"lasclass" : {

"clascode" : "26",

"clasitem" : "Overlap proximity to hydro breakline"

}

}}

This LiDAR project was contracted by ISGS.

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 7.0 Service Pack 1; ESRI ArcCatalog 9.3.0.1770

2 ft RMSE

The field survey for this three county area consisted of 90 hard surface (bare-earth) control points used for calibrating the unclassified LiDAR swath data.

An additional set of survey check points were collected over the combined Ford, Iroquois & Livingston flight plan for an independent QC of the LiDAR as validated against the swath LAS & DEM deliverable tiles. The points were collected over the following feature types: 95 hard surface points, 122 short grass points, 100 tall grass points, 100 tree & 99 brush points for a total of 516 QC check points in the three counties.

The required LiDAR elevation data values were derived within ArcGIS off the classified LAS and 4’ gsd raster grids. For each QC point location a LiDAR elevation value was derived and exported and the surface value subtracted from the survey elevation. These derived values were imported into Excel and comparisons were performed to generate statistics by ground cover type and for the overall dataset. Values reported are in US Feet due to the fact that all data was processed in IL State Plane, NAD83, East Zone however metric equivalents are stated in some cases. As indicated above the Swath LiDAR LAS hard surface Non-Vegetated Vertical Accuracy (NVA) meets project specifications RMSEz less than or equal to 10.0 cm (0.328 feet) & 19.6cm (0.643 feet) at the 95-percent confidence level. The calculated bare-earth RMSEz equals 5.5 cm (0.182 feet) and 10.9cm (0.358 feet) at the 95-percent confidence level. In addition, the DEM grids Vegetated Vertical Accuracy (VVA) meet project specifications less than or equal to 29.4cm (0.965 feet) at the 95th percentile. The DEM overall accuracy was 0.411 ft (12.5 cm) RMSEz.

All files are inspected to ensure that they conform to the specified file naming conventions, all files load in their correct geographic position, all files conform to the project specifications for file standard and content

All files load in their correct geographic position and conform to the USGS LiDAR Base Specifications.

Data is backed up to cloud storage.

The NOAA Office for Coastal Management (OCM) ingested references to the USGS GeoTIFF files that are hosted on Amazon Web Services (AWS), into the Digital Coast Data Access Viewer (DAV). The DAV accesses the raster data as it resides on AWS.