50125
2011 USGS-FEMA Lidar: King William County (VA)
va2011_usgs_fema_kingwilliam_m4726_metadata
Data Set
Published / External
49401
Lidar - partner (no harvest)
Project
Completed
2014-12
Dewberry collected LiDAR for ~3,341 square miles in various Virginia Counties, a part of Worcester County, and Hooper's Island. The acquisition was performed by Terrapoint. This metadata covers the LiDAR produced for the King William project area. The nominal pulse spacing for this project is 1.6 ft (0.5 meters). This project was collected with a sensor which collects intensity values for each discrete pulse extracted from the waveform. GPS Week Time, Intensity, Flightline and echo number attributes were provided for each LiDAR point. Dewberry used proprietary procedures to classify the LAS according to contract specifications: 1-Unclassified, 2-Ground, 7-Noise, 9-Water, 10-Ignored Ground due to breakline proximity, and 11-Withheld (reclassified by OCM to Class 15). Dewberry produced 3D breaklines and combined these with the final LiDAR data to produce seamless hydro flattened DEMs for the 415 tiles (5000 ft x 5000 ft) that cover the project area.
The purpose of this LiDAR data was to produce high accuracy 3D elevation products, including tiled LiDAR in LAS 1.2 format, 3D breaklines, and a 2.5 ft cell size hydro flattened Digital Elevation Models (DEM).
10769
A footprint of this data set may be viewed in Google Earth at:
https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/4726/supplemental/va2011_usgs_fema_kingwilliam_m4726.kmz
A report for this dataset is available at:
https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/4726/supplemental/va2011_usgs_fema_kingwilliam_m4726_surveyreport.pdf
Theme
ISO 19115 Topic Category
elevation
Theme
FEMA
Theme
USGS
Office for Coastal Management
Charleston
SC
Data Set
As Needed
las
Lidar points in LAZ format (Classes 1,2,7,9,10,15)
none
Any conclusions drawn from the analysis of this information are not the responsibility of USGS, FEMA, NOAA, the Office for Coastal Management or its partners.
Data Steward
2014-12
Organization
NOAA Office for Coastal Management
NOAA/OCM
coastal.info@noaa.gov
2234 South Hobson Ave
Charleston
SC
29405-2413
(843) 740-1202
https://coast.noaa.gov
NOAA Office for Coastal Management Home Page
Online Resource
Distributor
2014-12
Organization
NOAA Office for Coastal Management
NOAA/OCM
coastal.info@noaa.gov
2234 South Hobson Ave
Charleston
SC
29405-2413
(843) 740-1202
https://coast.noaa.gov
NOAA Office for Coastal Management Home Page
Online Resource
Metadata Contact
2014-12
Organization
NOAA Office for Coastal Management
NOAA/OCM
coastal.info@noaa.gov
2234 South Hobson Ave
Charleston
SC
29405-2413
(843) 740-1202
https://coast.noaa.gov
NOAA Office for Coastal Management Home Page
Online Resource
Point of Contact
2014-12
Organization
NOAA Office for Coastal Management
NOAA/OCM
coastal.info@noaa.gov
2234 South Hobson Ave
Charleston
SC
29405-2413
(843) 740-1202
https://coast.noaa.gov
NOAA Office for Coastal Management Home Page
Online Resource
Ground Condition
-77.370438879
-76.716798791
37.919034743
37.510110491
Range
2011-04-19
2011-10-27
Yes
Unclassified
This data can be obtained on-line at the following URL:
https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=4726;
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. These data depict the heights at the time of the survey and are only accurate for that time.
2014
https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=4726
2014-12
Organization
NOAA Office for Coastal Management
Customized Download
Create custom data files by choosing data area, product type, map projection, file format, datum, etc.
Zip
Zip
2014
https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/4726/index.html
2014-12
Organization
NOAA Office for Coastal Management
Bulk Download
Simple download of data files.
LAZ
LAS/LAZ - LASer
Zip
https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/4726/supplemental/va2011_usgs_fema_kingwilliam_m4726.kmz
Browse Graphic
Browse Graphic
kmz
This graphic shows the coverage of the 2011 USGS/FEMA Virginia King William County lidar collection.
2016-05-23
Date that the source FGDC record was last modified.
2017-11-14
Converted from FGDC Content Standards for Digital Geospatial Metadata (version FGDC-STD-001-1998) using 'fgdc_to_inport_xml.pl' script. Contact Tyler Christensen (NOS) for details.
2018-02-08
Partial upload of Positional Accuracy fields only.
2018-03-13
Partial upload to move data access links to Distribution Info.
These data are not attributed.
Lidar source compiled to meet 1.0 meter horizontal RMSE.; Quantitative Value: 1.0 meters, Test that produced the value: Dewberry does not perform independent horizontal accuracy testing on the LiDAR. LiDAR vendors perform calibrations on the LiDAR sensor and compare data to adjoing flight lines to ensure LiDAR meets the 1.0 meter horizontal accuracy standard at the 95% confidence level. Please see the final project report for more details.
The vertical accuracy of the Raw Swath LiDAR was tested by Dewberry using 4 open terrain points contained within the project boundary. These 4 checkpoints were used to compute the Fundamental Vertical Accuracy (FVA) and the Consolidated Vertical Accuracy (CVA). Project specifications required a FVA of 0.183 meters for open terrain and a CVA of 0.364 meters.
Appendix A, Guidance for Aerial Mapping and Surveying, to FEMAs Guidelines and Specifications for Flood Hazard Mapping Partners requires a minimum of 60 test points -- 20 each in a minimum of three land cover categories representative of the floodplain. FEMAs Procedure Memorandum No. 61 - Standards for Lidar and Other High Quality Digital Topography -- specifies that the positional accuracy of LiDAR shall be in accordance with ASPRS/NDEP standards for accuracy testing as well as the USGS Lidar Guidelines and Base Specifications, v13. All of these standards and guidelines require testing for Fundamental Vertical Accuracy (FVA), Supplemental Vertical Accuracy (SVA), and Consolidated Vertical Accuracy (CVA), using a minimum of 20 checkpoints each in a minimum of three land cover categories for a minimum total of 60 QA/QC checkpoints. Although tentative tests are performed on smaller subareas with fewer than 20 QA/QC checkpoints, Dewberrys final results will not be official until all areas are merged for testing of the total area with all project checkpoints.; Quantitative Value: 0.027 meters, Test that produced the value: This RMSE analysis was performed against the raw, unclassified Swath LAS. Based on the vertical accuracy testing conducted by Dewberry, using NSSDA and FEMA methodology, vertical accuracy at the 95% confidence level (called Accuracyz) is computed by the formula RMSEz x 1.9600. The dataset for the South Counties project area satisfies the criteria: Lidar dataset tested 0.079 meters vertical accuracy at 95% confidence level, based on RMSEz (0.027 m) x 1.9600. The Consolidated Vertical Acccuracy is 0.119 meters.
A visual qualitative assessment was performed to ensure data completeness and bare earth data cleanliness. No void or missing data, the bare earth surface is of good quality and data passes vertical accuracy specifications.
Data covers the tile scheme provided for the project area.
Classified lidar data
Organization
USGS
Originator
1
Establishment of survey points to support the LiDAR data collection. two existing published NGS stations (FX5374, FX5377) were observed in a GPS control network and used to establish one new point for the primary control for this site. FX5374, FX5377, 239DEB05 were observed and used to control all flight missions and static ground surveys. The following are the final coordinates of the control points used for this project: SurveyBlock, Station, Latitude(D M S Hem), Longitude(D M S Hem), H-Ell(m), H-MSL(m) Counties South, 239DEB05, 36 50 47.15799, -76 59 00.22918, -14.6087, 20.3903 Counties South, FX5374, 36 48 32.84206, -76 37 15.00850, -28.4893, 7.6452 Counties South, FX5377, 36 41 06.67117, -77 06 58.40345, -7.2248, 27.6380
2012-01-01T00:00:00
2
Airborne acquisition of Lidar GeoDigital used one Optech ALTM 3100EA system to collect the data. The Optech System was configured in the following method: Aircraft Speed 150 knots Data Acquisition Height 950 m AGL Swath Width 691.54 m Distance between Flight Lines 300.00 m Overlap 55 % Scanner Field Of View 22 +/- degrees (+/-2 degrees flagged as withheld) Pulse Repetition Rate 70 KHz Scan Frequency 40 Hz Number of Returns per Pulse 4 Discrete returns Beam Divergence 0.3 mRad Flight Line Length shorter than 70km Base Station Distance shorter than 40km Resultant Raw Point Density ~2 pt/m2 with overlap Aircraft platforms were used in the collection of this project: A Cessna 310 aircraft was used to conduct the aerial survey. The Cessna 310 is a fixed wing aircraft that have an endurance of approximately 5 hours. -GPS-IMU: High accuracy IMU (200Hz) and GPS information (1Hz) concerning the attitude and position of the sensor were acquired at the same time as the Laser data. Ground based GPS stations also acquired consecutive GPS information for the duration of the flights. A combination of Sokkia GSR 2600 and NovAtel DL-4+ dual-frequency GPS receivers were used to support the airborne operations of this survey. - Flights and Flight Lines The area is covered by several missions, a mission is defined as the block of acquisition between aircraft take-off and landing flown under good meteorological and GPS conditions, and each mission includes multiple flightlines. Number Of Missions: 18 List Of Missions: o112005a o112006a o112006b o112007a o112007b o112008a o112008b o112010a o112010b o112012a o112013a o112014a o112014b o112015a o112015b o112016a o112016b o112018a Number Of Flight Lines: 219
2012-01-01T00:00:00
3
- Airborne GPS Kinematic processing
Airborne GPS kinematic data was processed on-site using GrafNav kinematic On-The-Fly (OTF) software. Flights were flown with a minimum of 6 satellites in view (13o above the horizon) and with a PDOP of better than 4. Distances from base station to aircraft were kept to a maximum of 40 km, to ensure a strong OTF (On-The-Fly) solution. For all flights, the GPS data can be classified as excellent, with GPS residuals of 3cm average but no larger than 10 cm being recorded.
The Geoid09 geoid model, published by the NGS, was used to transform all ellipsoidal heights to orthometric.
2012-01-01T00:00:00
4
- Generation and Calibration of laser points
Laser data points are generated using Optech's software Dashmap. Those software combine the raw laser range and angle data file with the finalized GPS/IMU trajectory information.
Each mission is evaluated in Terrasolid's Terramatch software to correct any residual roll pitch heading misalignments, if necessary those values are to the data.
The resulting point cloud is projected into the desired coordinate system and created in LAS format. One file per swath, files bigger than 2Gb split in 2.
On a project level, a coverage check is carried out to ensure no slivers are present.
2012-01-01T00:00:00
5
- Mission to mission adjustments of Lidar data
All missions are validated and adjusted against the adjoining
missions for relative vertical biases and collected GPS static and kinematic
ground truthing points for absolute vertical accuracy purposes.
2012-01-01T00:00:00
6
-Deliverable Product Generation
Raw Lidar point are projected were reprojected from UTM zone 18 to the delivery projection State Plane Virginia, US Survey Feet.
*Raw Calibrated LIDAR Point Cloud
Raw LiDAR point cloud, was provided in the following formats/parameters:
- LAS V1.2, point record format 1, Adjusted GPS time, georeferencing information populated in header
- The following fields are included in the LAS file:
1. Adjusted GPS time reported to the nearest microsecond
2. Flight line ID
3. Easting (reported to the nearest 0.01ft)
4. Northing (reported to the nearest 0.01ft)
5. Elevation (reported to the nearest 0.01ft)
6. intensity
7. Echo number
8. Classification
9. Scan angle
10. Edge of scan
11. Scan direction
- Full swaths, all collected points delivered (except discarded flightline)
- The Withheld bit flags the last 2 degrees of the swath (Additional areas are classified with the withheld in areas where wind or vegetation affected the quality of the data long the edge of the flight line. The classification of the additional withheld areas does not affect the density of the data.)
- 1 file per swath, 1 swath per file (except when swath had to be divided in section for size or calibration)
2012-01-01T00:00:00
7
The NOAA Office for Coastal Management (OCM) received the topographic lidar files in LAZ format. The files contained lidar easting, northing, elevation, intensity, return number, etc. The data was received in Virginia State Plane South 4502 (US ft) and NAVD88 (US ft). OCM performed the following processing for data storage and Digital Coast provisioning purposes:
1. The files were reviewed and erroneous elevations were removed.
2. Class 11 points (Withheld) were reclassified to Class 15.
3. Data were transformed to Geographic coordinates and ellipsoid heights. The GEOID09 model was removed.
2014-11-07T00:00:00
Organization
NOAA Office for Coastal Management
NOAA/OCM
coastal.info@noaa.gov
2234 South Hobson Ave
Charleston
SC
29405-2413
(843) 740-1202
https://coast.noaa.gov
NOAA Office for Coastal Management Home Page
Online Resource
Classified lidar data
gov.noaa.nmfs.inport:50125
Anne Ball
2017-11-15T15:24:26
SysAdmin InPortAdmin
2023-10-17T16:12:16
2022-03-16
OCM Partners
OCMP
1002
Public
No
2022-03-16
1 Year
2023-03-16