San Diego CA 2014 Lidar QL 1

Geographic Extent: San Diego, California, covering approximately 20.5 square miles.

Dataset Description: San Diego, California 2014 Lidar project called for the Planning, Acquisition, processing and derivative products of lidar data to be collected at a nominal pulse spacing (NPS) of 0.35 meters. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base ldiar Specification, Version 1. Lidar data was delivered in RAW flight line swath format, processed to create Classified LAS 1.2 Files formatted to 118 individual 2500 ft x 2500 ft tiles, and corresponding Intensity Images and Bare Earth DEMs tiled to the same 2500 ft x 2500 ft schema, and Breaklines in Esri geodatabase format.

Ground Conditions: Lidar was collected in late 2014, 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, Photo Science established a total of 8 QA calibration control points and 20 Land Cover control points that were used to calibrate the lidar to known ground locations established throughout the San Diego, California project area.

Classified LAS files are used to show the manually reviewed bare earth surface. This allows the user to create Intensity Images, Breaklines and Raster DEM.

The purpose of these lidar data was to produce high accuracy 3D hydro-flattened Digital Elevation Model (DEM) with a 2 foot cell size.

These raw lidar point cloud data were used to create classified lidar LAS files, intensity images, 3D breaklines, hydro-flattened DEMs as necessary.

USGS Contract No. G10PC00026

CONTRACTOR: Photo Science, Inc.

Ground Control Points were acquired and calibrated by Photo Science, A Quantum Spatial Company

All Lidar data acquisition, calibration, and follow-on processing were completed by Aerographics.

The following are the USGS lidar fields in JSON:

{

"ldrinfo" : {

"ldrspec" : "USGS-NGP Base Lidar Specification v1.0",

"ldrsens" : "Optech Orion H300",

"ldrmaxnr" : "4",

"ldrnps" : "0.35",

"ldrdens" : "8.00",

"ldrfltht" : "617",

"ldrfltsp" : "100",

"ldrscana" : "24",

"ldrscanr" : "72.8",

"ldrpulsr" : "150",

"ldrpulsd" : "4",

"ldrpulsw" : "0.41",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.22",

"ldrswatw" : "252",

"ldrswato" : "26",

"ldrcrs" : "NAD_1983_2011_StatePlane_California_VI_FIPS_0406_Feet",

"ldrgeoid" : "National Geodetic Survey (NGS) Geoid12A"

},

"ldraccur" : {

"ldrchacc" : "-9999",

"rawfva" : "0.370",

"clsfva" : "0.375",

"clscva" : "0.200"

},

"lasinfo" : {

"lasver" : "1.2",

"lasprf" : "1",

"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 adding 128 to the standard classification values.",

"lasintr" : "8",

"lasclass" : {

"clascode" : "1",

"clasitem" : "Processed, but Unclassified"

},

"lasclass" : {

"clascode" : "2",

"clasitem" : "Bare earth ground"

},

"lasclass" : {

"clascode" : "7",

"clasitem" : "Noise"

},

"lasclass" : {

"clascode" : "9",

"clasitem" : "Water"

},

"lasclass" : {

"clascode" : "10",

"clasitem" : "Ignored Ground"

},

"lasclass" : {

"clascode" : "17",

"clasitem" : "Bridge Decks"

},

"lasclass" : {

"clascode" : "21",

"clasitem" : "Overlap Default (Unclassified)"

},

"lasclass" : {

"clascode" : "22",

"clasitem" : "Overlap Ground"

},

"lasclass" : {

"clascode" : "25",

"clasitem" : "Overlap Water"

}

}}

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 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.

MicroStation Version 8; TerraScan Version 15; TerraModeler Version 15; GeoCue Version 2014.1.21.1; ESRI ArcGIS 10.2; Global Mapper 15; ALS Post Processor 2.75 Build #25; Windows 7 Operating System \\psihq_nx3200\Projects\24982_San_Diego_133UA\ 266 GB and \\Matrix\LIDAR\24982_San_Diego_LiDAR 2.31 TB

The specifications require that only Fundamental Vertical Accuracy (FVA) be computed for raw lidar point cloud swath files.

The vertical accuracy value is the AccuracyZ at 95 percent Confidence Interval in feet. The FVA was tested using 20 independent survey check points located in open terrain. The survey checkpoints were distributed throughout the project area. The 20 independent check points were surveyed using GPS techniques. See survey report for additional survey methodologies. Elevations from the unclassified lidar surface were measured for the x,y location of each check point. Elevations interpolated from the lidar surface were then compared to the elevation values of the surveyed control. AccuracyZ has been tested to meet 18.13 cm Fundamental Vertical Accuracy at 95 Percent confidence level using RMSE(z) x 1.9600 as defined by the National Standards for Spatial Data Accuracy (NSSDA); assessed and reported using National Digital Elevation Program (NDEP)/ASRPS Guidelines.

Qualitative value:0.370, Test that produced the value:

The FVA was tested using 20 independent survey check points located in open terrain. The survey checkpoints were distributed throughout the project area. The 20 independent check points were surveyed using GPS techniques. See survey report for additional survey methodologies. Elevations from the unclassified lidar surface were measured for the x,y location of each check point. Elevations interpolated from the lidar surface were then compared to the elevation values of the surveyed control. The RMSE was computed to be 0.189 feet. AccuracyZ has been tested to meet 18.13 cm Fundamental Vertical Accuracy at 95 Percent confidence level using RMSE(z) x 1.9600 as defined by the National Standards for Spatial Data Accuracy (NSSDA); assessed and reported using National Digital Elevation Program (NDEP)/ASRPS Guidelines.

Datasets contain complete coverage of tiles.

No points have been removed or excluded.

A visual qualitative assessment was performed to ensure data completeness.

There are no void areas or missing data. The raw point cloud is of good quality and data passes Fundamental Vertical Accuracy specifications.

Classified LAS files were tested by Photo Science for both vertical and horizontal accuracy. All data is seamless from one tile to the next, no gaps or no data areas.