Slide Menu
Search Help Show/Hide Menu
Short Citation:
OCM Partners, 2023: 2011 FEMA Lidar: Southern Virginia Cities,

Item Identification

Title: 2011 FEMA Lidar: Southern Virginia Cities
Short Name: va2011_usgs_fema_southerncities_m4727_metadata
Status: Completed
Publication Date: 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 Southern Cities (Hampton and Portsmouth). The nominal pulse spacing for this project is 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. Dewberry produced 3D breaklines and combined these with the final LiDAR data to produce seamless hydro flattened DEMs for the 142 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 ft cell size hydro flattened Digital Elevation Models (DEM).



Supplemental Information:

A footprint of this data set may be viewed in Google Earth at:

A report for this dataset is available at:


Theme Keywords

Thesaurus Keyword
ISO 19115 Topic Category

Physical Location

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

Data Set Information

Data Set Scope Code: Data Set
Maintenance Frequency: As Needed
Data Presentation Form: las
Entity Attribute Overview:

Lidar points in LAZ format (Classes 1,2,7,9,10,15)

Entity Attribute Detail Citation:


Distribution Liability:

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.

Support Roles

Data Steward

CC ID: 691460
Date Effective From: 2014-12
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address:
Phone: (843) 740-1202


CC ID: 691462
Date Effective From: 2014-12
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address:
Phone: (843) 740-1202

Metadata Contact

CC ID: 691463
Date Effective From: 2014-12
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address:
Phone: (843) 740-1202

Point of Contact

CC ID: 691461
Date Effective From: 2014-12
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address:
Phone: (843) 740-1202


Currentness Reference: Ground Condition

Extent Group 1

Extent Group 1 / Geographic Area 1

CC ID: 1136189
W° Bound: -76.46057
E° Bound: -76.267738
N° Bound: 37.114795
S° Bound: 36.783062

Extent Group 1 / Time Frame 1

CC ID: 1136188
Time Frame Type: Range
Start: 2011-04-19
End: 2011-09-28

Spatial Information

Spatial Representation

Representations Used

Vector: Yes

Access Information

Security Class: Unclassified
Data Access Procedure:

This data can be obtained on-line at the following URL:;

Data Access Constraints:


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. These data depict the heights at the time of the survey and are only accurate for that time.

Distribution Information

Distribution 1

CC ID: 743168
Start Date: 2013
End Date: Present
Download URL:
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2014-12 - Present)
File Name: Customized Download

Create custom data files by choosing data area, product type, map projection, file format, datum, etc.

File Type: Zip
Compression: Zip

Distribution 2

CC ID: 743169
Start Date: 2013
End Date: Present
Download URL:
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2014-12 - Present)
File Name: Bulk Download

Simple download of data files.

File Type: LAZ
Compression: Zip



CC ID: 743171
URL Type:
Online Resource


CC ID: 743172
URL Type:
Online Resource


CC ID: 743173
Name: Browse Graphic
URL Type:
Browse Graphic
File Resource Format: kmz

This graphic shows the coverage of the 2011 USGS/FEMA Virginia Southern Cities lidar collection.

Activity Log

Activity Log 1

CC ID: 691479
Activity Date/Time: 2016-05-23

Date that the source FGDC record was last modified.

Activity Log 2

CC ID: 691478
Activity Date/Time: 2017-11-14

Converted from FGDC Content Standards for Digital Geospatial Metadata (version FGDC-STD-001-1998) using '' script. Contact Tyler Christensen (NOS) for details.

Activity Log 3

CC ID: 718731
Activity Date/Time: 2018-02-08

Partial upload of Positional Accuracy fields only.

Activity Log 4

CC ID: 743170
Activity Date/Time: 2018-03-13

Partial upload to move data access links to Distribution Info.

Data Quality


These data are not attributed.

Horizontal Positional Accuracy:

Lidar source compiled to meet 1.0 meter horizontal RMSE.; Quantitative Value: 1 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 m horizontal accuracy standard at the 95% confidence level. Please see the final project report for more details.

Vertical Positional Accuracy:

The vertical accuracy of the LiDAR was tested by Dewberry with 20 independently collected checkpoints. The survey checkpoints are distributed throughout the project area. These 20 checkpoints pertain only to open terrain land cover classification.

The 20 checkpoints were used to compute the Fundamental Vertical Accuracy (FVA). Project specifications required a FVA of 0.183 m for open terrain.; Quantitative Value: 0.088 meters, Test that produced the value: 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 Southern Cities project area satisfies the criteria:

Lidar dataset tested 0.171 m vertical accuracy at 95% confidence level, based on RMSEz (0.088 m) x 1.9600. This RMSE check was performed against the raw, unclassified Swath LAS.

Completeness Report:

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.

Conceptual Consistency:

Data covers the tile scheme provided for the project area.


Process Steps

Process Step 1

CC ID: 1136181

Establishment of survey points to support the LiDAR data collection. Two existing published NGS stations (AI7609, HU2327) were observed in a GPS control network and used to establish four new points for the primary control for this site. 1110312 was 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) Worcester, 1110312, N38 18 22.12367, W75 07 40.46389, -33.7921, 2.2581

Process Date/Time: 2011-03-01 00:00:00

Process Step 2

CC ID: 1136182

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.

Process Date/Time: 2011-03-01 00:00:00

Process Step 3

CC ID: 1136183

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

Process Date/Time: 2011-04-01 00:00:00

Process Step 4

CC ID: 1136184

Deliverable Product Generation Raw Lidar point 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 0.01m) 4. Northing (reported to the nearest 0.01m) 5. Elevation (reported to the nearest 0.01m) 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 3 degrees of the swath - 1 file per swath, 1 swath per file (except when swath had to be divided in section for size or calibration).

Process Date/Time: 2011-09-01 00:00:00

Process Step 5

CC ID: 1136185

Dewberry utilizes a variety of software suites for inventory management, classification, and data processing. All LiDAR related processes begin by importing the data into the GeoCue task management software. GeoCue allows the data to retain its delivered tiling scheme (5000 ft by 5000 ft). The tiled data is then opened in Terrascan where Dewberry uses proprietary ground classification routines to remove any non-ground points and generate an accurate ground surface. The ground routine consists of three main parameters (building size, iteration angle, and iteration distance); by adjusting these parameters and running several iterations of this routine an initial ground surface is developed. The building size parameter sets a roaming window size. Each tile is loaded with neighboring points from adjacent tiles and the routine classifies the data section by section based on this roaming window size. The second most important parameter is the maximum terrain angle, which sets the highest allowed terrain angle within the model. Once the ground routine has been completed a manual quality control routine is done using hillshades, cross-sections, and profiles within the Terrasolid software suite. After this QC step, a peer review and supervisor manual inspection is completed on a percentage of the classified tiles based on the project size and variability of the terrain. After the ground classification corrections were completed, the dataset was processed through a water classification routine that utilizes breaklines compiled by Dewberry to automatically classify hydrographic features. The water classification routine selects ground points within the breakline polygons and automatically classifies them as class 9, water. During this water classification routine, points which are in close proximity (1 m) to the hydrographic features are moved to class 10, an ignored ground. In addition to classes 1, 2, 8, 9, and 10, the project allows for a Class 7, noise points. This class was only used if needed when points could manually be identified as low/high points. Dewberry also used Class 11 - Withheld points.

The fully classified dataset is then processed through Dewberry's comprehensive quality control program.

The data was classified as follows:

Class 1 = Unclassified. This class includes vegetation, buildings, noise etc.

Class 2 = Ground

Class 7= Noise

Class 8= Model Key Points

Class 9 = Water

Class 10= Ignored Ground

Class 11= Withheld (later changed to class 15)

The LAS header information was verified to contain the following:

Class (Integer)

GPS Week Time (0.0001 seconds)

Easting (0.01 ft)

Northing (0.01 ft)

Elevation (0.01 ft)

Echo Number (Integer 1 to 4)

Echo (Integer 1 to 4)

Intensity (8 bit integer)

Flight Line (Integer)

Scan Angle (Integer degree)

Process Date/Time: 2011-09-01 00:00:00

Process Step 6

CC ID: 1136186

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 to conform to the Data Access Viewer schema.

3. Data were reprojected to geographic coordinates and ellipsoid heights (the geoid model was removed).

Process Date/Time: 2014-11-10 00:00:00
Process Contact: NOAA Office for Coastal Management (NOAA/OCM)
Phone (Voice): (843) 740-1202
Email Address:

Catalog Details

Catalog Item ID: 50126
GUID: gov.noaa.nmfs.inport:50126
Metadata Record Created By: Anne Ball
Metadata Record Created: 2017-11-15 15:24+0000
Metadata Record Last Modified By: SysAdmin InPortAdmin
Metadata Record Last Modified: 2023-08-15 17:09+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