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Data Set Info
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Spatial Info
Access Info
Distribution Info
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Tech Environment
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Catalog Details

Summary

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Short Citation
OCM Partners, 2024: 2018 USGS Lidar: Fairfax County, VA, https://www.fisheries.noaa.gov/inport/item/61290.
Full Citation Examples

Abstract

Product: These lidar data are processed Classified LAS 1.4 files, formatted to 1,765 individual 1000 m x 1000 m tiles; used to create intensity images, 3D breaklines and hydro-flattened DEMs as necessary.

Geographic Extent: Fairfax county, Virginia, covering approximately 597 square miles.

Dataset Description: Fairfax county, Virginia 2019 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 meter. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 1.3. The data was developed based on a horizontal projection/datum of NAD83 (2011), Conus Albers, meters and vertical datum of NAVD88 (GEOID12B), meters. Lidar data was delivered as processed Classified LAS 1.4 files, formatted to 1765 individual 1000 m x 1000 m tiles, as tiled Intensity Imagery, and as tiled bare earth DEMs; all tiled to the same 1000 m x 1000 m schema.

Ground Conditions: Lidar was collected in late 2018, 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 and meet ASPRS vertical accuracy guidelines, Dewberry established a total of 26 ground control points that were used to calibrate the lidar to known ground locations established throughout the Fairfax county, Virginia project area. An additional 74 independent accuracy checkpoints, 42 in Bare Earth and Urban landcovers (42 NVA points), 32 in Tall Grass and Brushland/Low Trees categories (32 VVA points), were used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the data.

The NOAA Office for Coastal Management (OCM) downloaded the laz files from this USGS site ftp://rockyftp.cr.usgs.gov/vdelivery/Datasets/Staged/Elevation/LPC/Projects/USGS_LPC_VA_Fairfax_County_2018/ and processed the data to the Data Access Viewer (DAV) and to https. The total number of files downloaded and processed was 1765.

The hydro breaklines were also downloaded and are available at the link provided in the URL section of this metadata record. Please note that 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.

Distribution Information

  • Create custom data files by choosing data area, product type, map projection, file format, datum, etc. A new metadata will be produced to reflect your request using this record as a base. Change to an orthometric vertical datum is one of the many options.

  • LAS/LAZ - LASer

    Bulk download of data files in LAZ format, geographic coordinates, orthometric heights. Note that the vertical datum (hence elevations) of the files here are different than described in this document. They will be in an orthometric datum.

Access Constraints:

None

Use Constraints:

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.

Controlled Theme Keywords

elevation, TERRAIN ELEVATION

Child Items

No Child Items for this record.

Contact Information

Point of Contact
NOAA Office for Coastal Management (NOAA/OCM)
coastal.info@noaa.gov
(843) 740-1202
https://coast.noaa.gov

Metadata Contact
NOAA Office for Coastal Management (NOAA/OCM)
coastal.info@noaa.gov
(843) 740-1202
https://coast.noaa.gov

Extents

Geographic Area 1

-77.584074° W, -77.027787° E, 39.064288° N, 38.589431° S

Time Frame 1
2018-12-06 - 2018-12-26

Item Identification

Title: 2018 USGS Lidar: Fairfax County, VA
Short Name: va2018_fairfax_m9164_metadata
Status: Completed
Publication Date: 2019-10-15
Abstract:

Product: These lidar data are processed Classified LAS 1.4 files, formatted to 1,765 individual 1000 m x 1000 m tiles; used to create intensity images, 3D breaklines and hydro-flattened DEMs as necessary.

Geographic Extent: Fairfax county, Virginia, covering approximately 597 square miles.

Dataset Description: Fairfax county, Virginia 2019 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 meter. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 1.3. The data was developed based on a horizontal projection/datum of NAD83 (2011), Conus Albers, meters and vertical datum of NAVD88 (GEOID12B), meters. Lidar data was delivered as processed Classified LAS 1.4 files, formatted to 1765 individual 1000 m x 1000 m tiles, as tiled Intensity Imagery, and as tiled bare earth DEMs; all tiled to the same 1000 m x 1000 m schema.

Ground Conditions: Lidar was collected in late 2018, 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 and meet ASPRS vertical accuracy guidelines, Dewberry established a total of 26 ground control points that were used to calibrate the lidar to known ground locations established throughout the Fairfax county, Virginia project area. An additional 74 independent accuracy checkpoints, 42 in Bare Earth and Urban landcovers (42 NVA points), 32 in Tall Grass and Brushland/Low Trees categories (32 VVA points), were used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the data.

The NOAA Office for Coastal Management (OCM) downloaded the laz files from this USGS site ftp://rockyftp.cr.usgs.gov/vdelivery/Datasets/Staged/Elevation/LPC/Projects/USGS_LPC_VA_Fairfax_County_2018/ and processed the data to the Data Access Viewer (DAV) and to https. The total number of files downloaded and processed was 1765.

The hydro breaklines were also downloaded and are available at the link provided in the URL section of this metadata record. Please note that 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.

Purpose:

To acquire detailed surface elevation data for use in conservation planning, design, research, floodplain mapping, dam safety assessments and elevation modeling, etc. 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 1 meter cell size. These lidar point cloud data were used to create intensity images, 3D breaklines, and hydro-flattened DEMs as necessary.

Supplemental Information:

USGS Contract No. G16PC00020 CONTRACTOR: Dewberry SUBCONTRACTOR: Axis Geospatial, LLC Lidar data were acquired and calibrated by Axis Geospatial Services. All follow-on processing was completed by the prime contractor.

The following are the USGS lidar fields in JSON:

{

"ldrinfo" : {

"ldrspec" : "U.S. Geological Survey (USGS) - National Geospatial Program (NGP) Lidar Base Specification v1.3",

"ldrsens" : "VQ-1560i",

"ldrmaxnr" : "7",

"ldrnps" : "0.35",

"ldrdens" : "8",

"ldranps" : "0.35",

"ldradens" : "8",

"ldrfltht" : "1303",

"ldrfltsp" : "160",

"ldrscana" : "58.52",

"ldrscanr" : "2000",

"ldrpulsr" : "376",

"ldrpulsd" : "3",

"ldrpulsw" : "0.9",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.25",

"ldrswatw" : "1460",

"ldrswato" : "30",

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

},

"ldraccur" : {

"ldrchacc" : "0.717",

"rawnva" : "0.177",

"rawnvan" : "41",

"clsnva" : "0.173",

"clsnvan" : "42",

"clsvva" : "0.124",

"clsvvan" : "32"

},

"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" : "16",

"lasclass" : {

"clascode" : "1",

"clasitem" : "Processed, but Unclassified"

},

"lasclass" : {

"clascode" : "2",

"clasitem" : "Bare Earth Ground"

},

"lasclass" : {

"clascode" : "7",

"clasitem" : "Low Noise"

},

"lasclass" : {

"clascode" : "9",

"clasitem" : "Water"

},

"lasclass" : {

"clascode" : "20",

"clasitem" : "Ignored Ground"

},

"lasclass" : {

"clascode" : "17",

"clasitem" : "Bridge Decks"

},

"lasclass" : {

"clascode" : "18",

"clasitem" : "High Noise"

}

}}

Keywords

Theme Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Science Keywords
EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION
ISO 19115 Topic Category
elevation
UNCONTROLLED
None erosion

Spatial Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Location Keywords
CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA
Global Change Master Directory (GCMD) Location Keywords
CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA > VIRGINIA
Global Change Master Directory (GCMD) Location Keywords
VERTICAL LOCATION > LAND SURFACE
UNCONTROLLED
None Continent > North America > United States Of America > Virginia > Fairfax County

Instrument Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Instrument Keywords
LIDAR > Light Detection and Ranging

Platform Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Platform Keywords
Airplane > Airplane

Physical Location

Organization: Office for Coastal Management
City: Charleston
State/Province: SC

Data Set Information

Data Set Scope Code: Data Set
Data Set Type: Elevation
Maintenance Frequency: None Planned
Data Presentation Form: Model (digital)
Distribution Liability:

Any conclusions drawn from the analysis of this information are not the responsibility of USGS, NOAA, the Office for Coastal Management or its partners.

Data Set Credit: Dewberry

Support Roles

Data Steward

CC ID: 940291
Date Effective From: 2020
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address: coastal.info@noaa.gov
Phone: (843) 740-1202
URL: https://coast.noaa.gov

Distributor

CC ID: 940290
Date Effective From: 2020
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address: coastal.info@noaa.gov
Phone: (843) 740-1202
URL: https://coast.noaa.gov

Metadata Contact

CC ID: 940292
Date Effective From: 2020
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address: coastal.info@noaa.gov
Phone: (843) 740-1202
URL: https://coast.noaa.gov

Point of Contact

CC ID: 940293
Date Effective From: 2020
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address: coastal.info@noaa.gov
Phone: (843) 740-1202
URL: https://coast.noaa.gov

Extents

Currentness Reference: Ground Condition

Extent Group 1

Extent Group 1 / Geographic Area 1

CC ID: 1144953
W° Bound: -77.584074
E° Bound: -77.027787
N° Bound: 39.064288
S° Bound: 38.589431

Extent Group 1 / Time Frame 1

CC ID: 1144952
Time Frame Type: Range
Start: 2018-12-06
End: 2018-12-26

Spatial Information

Spatial Representation

Representations Used

Grid: No
Vector: Yes
Text / Table: No
TIN: No
Stereo Model: No
Video: No

Vector Representation 1

CC ID: 940284
Point Object Present?: Yes
Point Object Count: 46889000362

Reference Systems

Reference System 1

CC ID: 1144950

Coordinate Reference System

CRS Type: Geographic 3D
EPSG Code: EPSG:6319
EPSG Name: NAD83(2011)
See Full Coordinate Reference System Information

Access Information

Security Class: Unclassified
Data Access Procedure:

Data is available online for bulk and custom downloads.

Data Access Constraints:

None

Data Use Constraints:

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.

Distribution Information

Distribution 1

CC ID: 940297
Start Date: 2020-07-29
End Date: Present
Download URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=9164/details/9164
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2020 - Present)
File Name: Customized Download
Description:

Create custom data files by choosing data area, product type, map projection, file format, datum, etc. A new metadata will be produced to reflect your request using this record as a base. Change to an orthometric vertical datum is one of the many options.

File Type (Deprecated): Zip
Compression: Zip

Distribution 2

CC ID: 940298
Start Date: 2020-07-29
End Date: Present
Download URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9164/index.html
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2020 - Present)
File Name: Bulk Download
Description:

Bulk download of data files in LAZ format, geographic coordinates, orthometric heights. Note that the vertical datum (hence elevations) of the files here are different than described in this document. They will be in an orthometric datum.

File Type (Deprecated): LAZ
Distribution Format: LAS/LAZ - LASer
Compression: Zip

URLs

URL 1

CC ID: 940286
URL: https://coast.noaa.gov/dataviewer/
Name: NOAA's Office for Coastal Management (OCM) Data Access Viewer (DAV)
URL Type:
Online Resource
File Resource Format: HTML
Description:

The Data Access Viewer (DAV) allows a user to search for and download elevation, imagery, and land cover data for the coastal U.S. and its territories. The data, hosted by the NOAA Office for Coastal Management, can be customized and requested for free download through a checkout interface. An email provides a link to the customized data, while the original data set is available through a link within the viewer.

URL 2

CC ID: 940287
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9164/supplemental/va2018_fairfax_m9164.kmz
Name: Browse graphic
URL Type:
Browse Graphic
File Resource Format: KML
Description:

This graphic displays the footprint for this lidar data set.

URL 3

CC ID: 940288
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9164/supplemental/20191022_VA_Fairfax_County_Lidar_Report.pdf
Name: Dataset report
URL Type:
Online Resource
File Resource Format: PDF
Description:

Link to data set report.

URL 4

CC ID: 940324
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9164/breaklines/
Name: Hydro breaklines
URL Type:
Online Resource
Description:

Link to data set breaklines.

Technical Environment

Description:

Riegl processing software; GeoCue; MicroStation; Terrasolid Suite; Esri Arc 10.6; Windows 10

Data Quality

Vertical Positional Accuracy:

The project specifications require that only Non-Vegetated Vertical Accuracy (NVA) be computed for raw lidar point cloud swath files. The required accuracy (ACCz) is: 19.6 cm at a 95% confidence level, derived according to NSSDA, i.e., based on RMSE of 10 cm in the bare earth and urban land cover classes. The NVA was tested with 41 checkpoints located in bare earth and urban (non-vegetated) areas. Note: one checkpoint was removed from the swath NVA testing because a vehicle was parked at the xy location of the survey checkpoint. As non-ground points have not been separated from ground points at this stage, the point was excluded from swath NVA testing but was used during classified lidar and DEM testing. These check points were not used in the calibration or post processing of the lidar point cloud data. The checkpoints were distributed throughout the project area and 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 points. AccuracyZ has been tested to meet 19.6 cm or better Non-Vegetated Vertical Accuracy at 95% 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.

Tested 0.173 meters NVA at a 95% confidence level (8.8 cm RMSE) using RMSE(z) x 1.9600 as defined by the National Standards for Spatial Data Accuracy (NSSDA). The NVA of the raw lidar point cloud swath files was calculated against TINs derived from the final calibrated and controlled swath data using 41 independent checkpoints located in Bare Earth and Urban land cover classes.

Completeness Report:

These 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. The raw point cloud is of good quality and data passes Non-Vegetated Vertical Accuracy specifications. Due to flight restrictions near the White House and National Mall, Dewberry was unable to provide full tiles along some parts of the Potomac River, which are in close proximty to Washington, D.C. There are 13 tiles affected and these void areas comprise approximately 0.29 square miles. A shapefile identifying these void areas is delivered with this dataset.

Conceptual Consistency:

Data covers the entire area specified for this project.

Data Management

Have Resources for Management of these Data Been Identified?: Yes
Approximate Percentage of Budget for these Data Devoted to Data Management: Unknown
Do these Data Comply with the Data Access Directive?: Yes
Actual or Planned Long-Term Data Archive Location: NCEI-CO
How Will the Data Be Protected from Accidental or Malicious Modification or Deletion Prior to Receipt by the Archive?:

Data is backed up to tape and to cloud storage.

Lineage

Lineage Statement:

Data collected by Dewberry for the USGS. NOAA OCM downloaded laz files from the USGS rockyftp site and processed them to make available on the Data Access Viewer (DAV).

Sources

USGS

CC ID: 1144946

Process Steps

Process Step 1

CC ID: 1144947
Description:

The boresight for each lift was done individually as the solution may change slightly from lift to lift. The following steps describe the Raw Data Processing and Boresight process: 1) Technicians processed the raw data to LAS format flight lines using the final GPS/IMU solution. This LAS data set was used as source data for boresight. 2) Technicians first used Prime Contractor, LLC proprietary and commercial software to calculate initial boresight adjustment angles based on sample areas selected in the lift. These areas cover calibration flight lines collected in the lift, cross tie and production flight lines. These areas are well distributed in the lift coverage and cover multiple terrain types that are necessary for boresight angle calculation. The technician then analyzed the results and made any necessary additional adjustment until it is acceptable for the selected areas. 3) Once the boresight angle calculation was completed for the selected areas, the adjusted settings were applied to all of the flight lines of the lift and checked for consistency. The technicians utilized commercial and proprietary software packages to analyze how well flight line overlaps match for the entire lift and adjusted as necessary until the results met the project specifications. 4) Once all lifts were completed with individual boresight adjustment, the technicians checked and corrected the vertical misalignment of all flight lines and also the matching between data and ground truth. The relative accuracy was less than or equal to 6 cm RMSEz within individual swaths and less than or equal to 8 cm RMSEz or within swath overlap (between adjacent swaths). 5) The technicians ran a final vertical accuracy check of the boresighted flight lines against the surveyed check points after the z correction to ensure the requirement of NVA = 19.6 cm 95% Confidence Level (Required Accuracy) was met. Point classification was performed according to USGS Lidar Base Specification 1.3, and breaklines were collected for water features. Bare earth DEMs were exported from the classified point cloud using collected breaklines for hydroflattening. Synthetic points generated by Riegl processing software are present in this dataset and were used to fill MTA zones. Please see the final project report for more details on the synthetic points.

Process Date/Time: 2019-01-01 00:00:00

Process Step 2

CC ID: 1144948
Description:

LAS Point Classification: The point classification is performed as described below. The bare earth surface is then manually reviewed to ensure correct classification on the Class 2 (Ground) points. After the bare-earth surface is finalized, it is then used to generate all hydro-breaklines through heads-up digitization. All ground (ASPRS Class 2) lidar data inside of the Lake Pond and Double Line Drain hydro flattening breaklines were then classified to water (ASPRS Class 9) using TerraScan macro functionality. A buffer of 0.35 meters was also used around each hydro-flattened feature to classify these ground (ASPRS Class 2) points to Ignored ground (ASPRS Class 20). All Lake Pond Island and Double Line Drain Island features were checked to ensure that the ground (ASPRS Class 2) points were reclassified to the correct classification after the automated classification was completed. All overlap data was processed through automated functionality provided by TerraScan to classify the overlapping flight line data to approved classes by USGS. The overlap data was classified using standard LAS overlap bit. These classes were created through automated processes only and were not verified for classification accuracy. Due to software limitations within TerraScan, these classes were used to trip the withheld bit within various software packages. These processes were reviewed and accepted by USGS through numerous conference calls and project study areas. All data was manually reviewed and any remaining artifacts removed using functionality provided by TerraScan and TerraModeler. Global Mapper us used as a final check of the bare earth dataset. GeoCue was then used to create the deliverable industry-standard LAS files for both the All Point Cloud Data and the Bare Earth. Dewberry proprietary software was used to perform final statistical analysis of the classes in the LAS files, on a per tile level to verify final classification metrics and full LAS header information.

Process Date/Time: 2019-10-09 00:00:00

Process Step 3

CC ID: 1144949
Description:

The NOAA Office for Coastal Management (OCM) downloaded the laz files from this USGS site:

ftp://rockyftp.cr.usgs.gov/vdelivery/Datasets/Staged/Elevation/LPC/Projects/USGS_LPC_VA_Fairfax_County_2018/

These files were processed to the Data Access Viewer (DAV) and https. The total number of files downloaded and processed was 1765.

The data were in Albers Equal Area (NAD83 2011), meters, coordinates and NAVD88 (Geoid12B) elevations in meters. The data were classified as: 1 - Unclassified, 2 - Ground, 7 - Low Noise, 9 - Water, 17 - Bridge Decks, 18 - High Noise, 20 - Ignored Ground. OCM processed all classifications of points to the Digital Coast Data Access Viewer (DAV). Classes available on the DAV are: 1, 2, 7, 9, 17, 18, 20.

OCM performed the following processing on the data for Digital Coast storage and provisioning purposes:

1. An internal OCM script was run to check the number of points by classification and by flight ID and the gps and intensity ranges.

2. Internal OCM scripts were run on the laz files to convert from orthometric (NAVD88) elevations to ellipsoid elevations using the Geoid12B model, to convert from Albers Equal Area (NAD83 2011) coordinates in meters to geographic coordinates, to assign the geokeys, to sort the data by gps time and zip the data to database and to http.

Process Date/Time: 2020-07-28 00:00:00
Process Contact: Office for Coastal Management (OCM)

Catalog Details

Catalog Item ID: 61290
GUID: gov.noaa.nmfs.inport:61290
Metadata Record Created By: Rebecca Mataosky
Metadata Record Created: 2020-07-29 09:44+0000
Metadata Record Last Modified By: SysAdmin InPortAdmin
Metadata Record Last Modified: 2023-10-17 16:12+0000
Metadata Record Published: 2022-03-16
Owner Org: OCMP
Metadata Publication Status: Published Externally
Do Not Publish?: N
Metadata Last Review Date: 2022-03-16
Metadata Review Frequency: 1 Year
Metadata Next Review Date: 2023-03-16