2015 - 2016 LARIAC Lidar: Los Angeles Region, CA

Geographic Extent: This dataset is lidar point cloud data, which encompasses the entirety of the LARIAC4 project, approximately 4214 square miles. Dataset Description: This dataset consists of 13,810 lidar point cloud LAS tiled files. Each LAS file contains lidar point information, which has been calibrated, controlled, and classified. Each file represents a separate tile of lidar. Ground Conditions: water at normal levels; no unusual inundation; no snow.

The NOAA Office for Coastal Management (OCM) downloaded this lidar data from the USGS site: ftp://rockyftp.cr.usgs.gov/vdelivery/Datasets/Staged/Elevation/LPC/Projects/USGS_LPC_CA_LosAngeles_2016_LAS_2018/ and processed the data to be available on the Digital Coast Data Access Viewer (DAV). NOAA Office for Coastal Management processed all classifications of points to the Digital Coast Data Access Viewer (DAV). Classes available on the DAV are: 1 (Unclassified), 2 (Ground), 7 (Low Noise) , 9 (Water), 10 (Ignored Ground), 17 (Bridges), 18 (High Noise).

In addition to these lidar point data, the bare earth Digital Elevation Models (DEM) created from the lidar point data are also available. These data are are available for custom download at the link provided in the URL section of this metadata record.

Breakline data are also available. These data are are available for download at the link provided in the URL section of this metadata record. These products have not been reviewed by the NOAA Office for Coastal Management (OCM) and any conclusions drawn from the analysis of this information are not the responsibility of NOAA or OCM.

The purpose of this lidar data was to support generation of ortho imagry, 3D visualization, change detection, and 1 and 2 foot contour generation with breakline data for the Los Angeles Region Imagery Acquisition Consortium, LARIAC4. These raw lidar point cloud data were used to create classified lidar LAS files, intensity images, 3D breaklines, hydro-flattened DEMs as necessary.

CONTRACTOR: Pictometry International, Inc.

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" : "0.466485",

"ldrdens" : "4.5954",

"ldranps" : "0.466485",

"ldradens" : "4.5954",

"ldrfltht" : "6000",

"ldrfltsp" : "122.5",

"ldrscana" : "20",

"ldrscanr" : "60",

"ldrpulsr" : "300",

"ldrpulsd" : "10",

"ldrpulsw" : "3",

"ldrwavel" : "1064",

"ldrmpia" : "4",

"ldrbmdiv" : "0.25",

"ldrswatw" : "1330.67",

"ldrswato" : "30",

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

},

"ldraccur" : {

"ldrchacc" : "0.5",

"rawnva" : "0.0925",

"rawnvan" : "27",

"clsnva" : "0.0925",

"clsnvan" : "27",

"clsvva" : "0.188",

"clsvvan" : "123"

},

"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 using the standard LAS overlap bit.",

"lasintr" : "12-bit",

"lasclass" : {

"clascode" : "1",

"clasitem" : "Default/Unclassified"

},

"lasclass" : {

"clascode" : "2",

"clasitem" : "Bare earth"

},

"lasclass" : {

"clascode" : "7",

"clasitem" : "Noise (low or high; manually identified; if needed)"

},

"lasclass" : {

"clascode" : "9",

"clasitem" : "Water"

},

"lasclass" : {

"clascode" : "10",

"clasitem" : "Ignored Ground (Breakline proximity)"

},

"lasclass" : {

"clascode" : "17",

"clasitem" : "Bridges"

},

"lasclass" : {

"clascode" : "18",

"clasitem" : "High noise"

}

}}

In no event shall the creators, custodians, or distributors of these data be liable for any damages arising out of its use, or from the inability of the customer to use these data for their intended application.

Any conclusions drawn from the analysis of this information are not the responsibility of LARIAC, Pictometry, USGS, 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 Version 6.1 (Build 7601) Service Pack 1; Esri ArcGIS 10.2.1.3497

NVA (Non-vegetated Vertical Accuracy) is determined with check points located only in non-vegetated terrain, including open terrain (grass, dirt, sand, and/or rocks) and urban areas, where there is a very high probability that the lidar sensor will have detected the bare-earth ground surface and where random errors are expected to follow a normal error distribution. The NVA determines how well the calibrated lidar sensor performed. With a normal error distribution, the vertical accuracy at the 95% confidence level is computed as the vertical root mean square error (RMSEz) of the checkpoints x 1.9600. For the Lariac4 lidar project, vertical accuracy must be 0.64 ft or less based on an RMSEz of 0.328 ft x 1.9600.

This lidar dataset was tested to meet ASPRS Positional Accuracy Standards for Digital Geospatial Data (2014) for a 0.33 ft RMSEz Vertical Accuracy Class. Actual NVA accuracy was found to be RMSEz =0.32 ft (9.8 cm), equating to +/- 0.63 ft (19.2 cm) at 95% confidence level. Actual VVA accuracy was found to be +/- 0.53 ft (16.1 cm) at the 95th percentile.

These classified LAS data files include all data points collected. No points have been removed or excluded. A visual qualitative assessment was performed to ensure data completeness. No void areas or missing data exist. The raw point cloud is of good quality and data passes Fundamental Vertical Accuracy specifications.

Data cover the entire area specified for this project.