Slide Menu
Maintenance Notice: Tuesday May 21 @ 12pm-1:30pm Eastern. InPort and its associated services will be under maintenance and unavailable for the deployment of InPort Release 5.3.6. Downtime Schedule Tuesday, May 21, 2024 12:00pm - 1:30pm Eastern / 9:00am - 10:30am Pacific / 6:00am - 8:30am Hawaii Impacted Areas - InPort Website: https://www.fisheries.noaa.gov/inport - InPort WAF: h...
View All
Search Help Show/Hide Menu
Short Citation:
OCM Partners, 2024: 2014 USGS NRCS Lidar: Choctaw and Washington Counties, AL, https://www.fisheries.noaa.gov/inport/item/64494.

Item Identification

Title: 2014 USGS NRCS Lidar: Choctaw and Washington Counties, AL
Short Name: 2014 USGS NRCS lidar Alabama m9276
Status: Completed
Publication Date: 2014-12-22
Abstract:

This is a subset of data covering Alabama counties of Choctaw and Washington.

The full collection data set is comprised of lidar point cloud data, raster DEM, hydrologic 3-d breaklines, raster intensity, survey control, project tile index, and project data extent. This task order requires lidar data to be acquired in two separate AOI's over 10 counties in Mississippi; Attala, Leake, Lexington, Montgomery, Scott, Smith, Webster Counties and a portion of Carroll, Choctaw and Jasper Counties and two counties in Alabama; Washington and Choctaw. AOI is approximately 7,400 square miles.

The lidar sensor uses a combination of laser range finding, GPS positioning, and inertial measurement technologies. The lidar systems collect data point clouds that are used to produce highly detailed Digital Elevation Models (DEMs) of the earth's terrain, man-made structures, and vegetation. The task required the LiDAR data to be collected at a nominal pulse spacing (NPS) of 0.7 meters. The final products include classified LAS, one (1) meter pixel raster DEMs of the bare-earth surface in ERDAS IMG Format, and 8-bit intensity images. Each LAS file contains lidar point information, which has been calibrated, controlled, and classified. Additional deliverables include hydrologic breakline data, control data, tile index, lidar processing and survey reports in PDF format, FGDC metadata files for each data deliverable in .xml format, and LAS swath data. Collected swath files that were that were larger than 2GB were provided in multiple sub-swath files, each less than 2GB. Ground conditions: Water at normal levels; no unusual inundation; no snow; leaf off.

This metadata record only covers the classified LAS data.

Contract Information:

TASK NAME: USGS-NRCS Laurel MS 0.7m NPS LIDAR

Lidar Data Acquisition and Processing Production Task

USGS Contract No. G10PC00057

Task Order No. G13PD01086

Woolpert Order No. 073741

CONTRACTOR: Woolpert, Inc.

Purpose:

The purpose of this project is for lidar mapping services in support of the USGS for task name USGS Laurel MS 0.7m NPS Lidar Task Order.

Supplemental Information:

The following are the USGS lidar fields in JSON:

{

"ldrinfo" : {

"ldrspec" : "USGS NGP Base Specifications v1",

"ldrsens" : "Leica ALS70/Optech Gemini",

"ldrmaxnr" : "4/4",

"ldrnps" : "0.7",

"ldrdens" : "2",

"ldrfltht" : "1981/1524",

"ldrfltsp" : "150/130",

"ldrscana" : "40/24",

"ldrscanr" : "42.3/46",

"ldrpulsr" : "272/125",

"ldrpulsd" : "5/7",

"ldrpulsw" : "5/7",

"ldrwavel" : "1064/1064",

"ldrmpia" : "1/1",

"ldrbmdiv" : "0.22/.25",

"ldrswatw" : "1442/721",

"ldrswato" : "25/30",

"ldrcrs" : "NAD_1983(2011)_UTM_Zone_16N_Meters",

"ldrgeoid" : "GEOID12A"

},

"ldraccur" : {

"ldrchacc" : "0.360",

"rawfva" : "0.129",

"clsfva" : "0.031",

"clscva" : "0.207",

"clssvas" : {

"svalctyp" : "Urban",

"svavalue" : "0.180"

},

"clssvas" : {

"svalctyp" : "Tall Weeds and Crops",

"svavalue" : "0.228"

},

"clssvas" : {

"svalctyp" : "Brush Lands and Trees",

"svavalue" : "0.261"

},

"clssvas" : {

"svalctyp" : "Forested and Fully Grown",

"svavalue" : "0.177"

}

},

"lasinfo" : {

"lasver" : "1.2",

"lasprf" : "1",

"laswheld" : "Geometrically unreliable points were identified using a combination of automated and manual techniques and subsequently classified as swath overlap and or noise.",

"lasolap" : "swath overlap points were identified in these files by adding 16 to the standard classication values",

"lasintr" : "8",

"lasclass" : {

"clascode" : "1",

"clasitem" : "default/unclassified"

},

"lasclass" : {

"clascode" : "2",

"clasitem" : "Bare-earth"

},

"lasclass" : {

"clascode" : "7",

"clasitem" : "All noise"

},

"lasclass" : {

"clascode" : "9",

"clasitem" : "Water"

},

"lasclass" : {

"clascode" : "10",

"clasitem" : "Ignored ground"

},

"lasclass" : {

"clascode" : "17",

"clasitem" : "Overlap default/unclassified"

},

"lasclass" : {

"clascode" : "18",

"clasitem" : "Overlap ground"

}

}}

Keywords

Theme Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Science Keywords
EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION
Global Change Master Directory (GCMD) Science Keywords
EARTH SCIENCE > OCEANS > COASTAL PROCESSES > COASTAL ELEVATION
ISO 19115 Topic Category
elevation
UNCONTROLLED
None beach
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
VERTICAL LOCATION > LAND SURFACE

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: As Needed
Data Presentation Form: Model (digital)
Distribution Liability:

Woolpert prepared the original data as set forth in the Scope of Services, in accordance with reasonable care and due diligence as set forth in this Agreement, however, due to the easily alterable nature of electronic media, files, documents, and other deliverables, Woolpert, Inc. makes no warranties, either expressed or implied, with respect to the accuracy, completeness, merchantability, or fitness for any particular purpose, including, but not limited to, use of any/all data as described within this metadata file, by any user of this data. Any use will be at the end-user’s sole risk.

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

Data Set Credit: Woolpert, USGS, USDA/NRCS

Support Roles

Data Steward

CC ID: 1056632
Date Effective From: 2021
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: 1056631
Date Effective From: 2021
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: 1056633
Date Effective From: 2021
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: 1056634
Date Effective From: 2021
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: 1145840
W° Bound: -90.73
E° Bound: -87.63
N° Bound: 33.79
S° Bound: 31.01

Extent Group 1 / Time Frame 1

CC ID: 1145824
Time Frame Type: Discrete
Start: 2014-01-07

Extent Group 1 / Time Frame 2

CC ID: 1145825
Time Frame Type: Discrete
Start: 2014-01-08

Extent Group 1 / Time Frame 3

CC ID: 1145826
Time Frame Type: Discrete
Start: 2014-01-09

Extent Group 1 / Time Frame 4

CC ID: 1145827
Time Frame Type: Discrete
Start: 2014-01-11

Extent Group 1 / Time Frame 5

CC ID: 1145828
Time Frame Type: Discrete
Start: 2014-01-12

Extent Group 1 / Time Frame 6

CC ID: 1145829
Time Frame Type: Discrete
Start: 2014-01-14

Extent Group 1 / Time Frame 7

CC ID: 1145830
Time Frame Type: Discrete
Start: 2014-01-15

Extent Group 1 / Time Frame 8

CC ID: 1145831
Time Frame Type: Discrete
Start: 2014-01-16

Extent Group 1 / Time Frame 9

CC ID: 1145832
Time Frame Type: Discrete
Start: 2014-01-17

Extent Group 1 / Time Frame 10

CC ID: 1145833
Time Frame Type: Discrete
Start: 2014-01-18

Extent Group 1 / Time Frame 11

CC ID: 1145834
Time Frame Type: Discrete
Start: 2014-01-19

Extent Group 1 / Time Frame 12

CC ID: 1145835
Time Frame Type: Discrete
Start: 2014-01-20

Extent Group 1 / Time Frame 13

CC ID: 1145836
Time Frame Type: Discrete
Start: 2014-01-21

Extent Group 1 / Time Frame 14

CC ID: 1145837
Time Frame Type: Discrete
Start: 2014-01-22

Extent Group 1 / Time Frame 15

CC ID: 1145838
Time Frame Type: Discrete
Start: 2014-01-25

Extent Group 1 / Time Frame 16

CC ID: 1145839
Time Frame Type: Discrete
Start: 2014-02-15

Spatial Information

Spatial Resolution

Horizontal Distance: 0.7 Meter

Spatial Representation

Representations Used

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

Vector Representation 1

CC ID: 1056625
Point Object Present?: Yes
Point Object Count: 28767526622

Access Information

Security Class: Unclassified
Data Access Procedure:

Data is available online for bulk or 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: 1056653
Start Date: 2021-04-02
End Date: Present
Download URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=9276/details/9276
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2021 - 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: 1056654
Start Date: 2021-04-02
End Date: Present
Download URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9276/index.html
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2021 - 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: 1056627
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: 1056628
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9276/supplemental/extent_al_choctaw_wash_m9276.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: 1056629
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9276/supplemental/MS_Washington-Choctaw_2014_QA-Report.pdf
Name: Dataset report
URL Type:
Online Resource
File Resource Format: PDF
Description:

Link to data set report.

Technical Environment

Description:

Microsoft Windows 7 Version 6.1 (Build 7600); ArcMap 10.2; ArcCatalog 10.2; TerraScan ver. 14.003; TerraModeler ver. 14.003; Geocue 2012.1.27.5; LP360 2011.1.54.1. Approximate size of entire delivery dataset = 6.5 TB

Data Quality

Horizontal Positional Accuracy:

Compiled to meet 0.360 meters horizontal accuracy at 95 percent confidence level. Quantitative value: 0.360m (36cm), Test that produced the valued: Lidar system specifications are available in the project report

Vertical Positional Accuracy:

LAS data covering the Laurel MS Lidar 0.7 meter NPS Lidar Task Order was compared to independent survey control points to determine the FVA of the LAS Swath and of the Bare-Earth DEM. In addition, this LAS data was compared to independent supplemental points from categories: Bare Earth Open Terrain, Urban, Tall Weeds/Crops, and Brush Lands and Trees.

Reported Values:

Raw LAS Swath Fundamental Vertical Accuracy (FVA) Tested 0.129 meters fundamental vertical accuracy at a 95 percent confidence level, derived according to NSSDA, using 0.066 meters (RMSEz) x 1.96000 as defined by the National Standards for Spatial Data Accuracy (NSSDA); assessed and reported using National Digital Elevation Program (NDEP)/ASPRS Guidelines.

Bare-Earth DEM Fundamental Vertical Accuracy (FVA) Tested 0.137 meters fundamental vertical accuracy at a 95 percent confidence level, derived according to NSSDA, in open terrain using 0.07 meters (RMSEz) x 1.96000 as defined by the National Standards for Spatial Data Accuracy (NSSDA); assessed and reported using National Digital Elevation Program (NDEP)/ASPRS Guidelines.

Urban Land Cover Classification Supplemental Vertical Accuracy (SVA) Tested 0.180 meters supplemental vertical accuracy at the 95th percentile in the Urban supplemental class reported using National Digital Elevation Program (NDEP)/ASPRS Guidelines and tested against the DEM. Urban Errors larger than 95th percentile include:

Tall Weeds/Crops Land Cover Classification Supplemental Vertical Accuracy (SVA) Tested 0.228 meters supplemental vertical accuracy at the 95th percentile in the Tall Weeds/Crops supplemental class reported using National Digital Elevation Program (NDEP)/ASPRS Guidelines and tested against the DEM. There were no Tall Weeds/Crops Errors exceeding the 95th percentile. Tall Weeds/Crops Errors at the 95th percentile include:

Brushlands/Trees Land Cover Classification Supplemental Vertical Accuracy (SVA) Tested 0.261 meters supplemental vertical accuracy at the 95th percentile in the Brushlands/Trees supplemental class reported using National Digital Elevation Program (NDEP)/ASPRS Guidelines and tested against the DEM. Brushlands/Trees Errors larger than 95th percentile include:

Forested and Fully Grown Land Cover Classification Supplemental Vertical Accuracy (SVA) Tested 0.177 meters supplemental vertical accuracy at the 95th percentile in the Forest supplemental class reported using National Digital Elevation Program (NDEP)/ASPRS Guidelines and tested against the DEM.

Reviewed Values:

LAS Swath Fundamental Vertical Accuracy (FVA) using 24 checkpoints is 7.5 cm RMSE (14.7 cm at a 95 percent confidence level).

Bare-Earth DEM Fundamental Vertical Accuracy (FVA) using 24 checkpoints is 7.9 cm RMSE (17.0 cm at a 95 percent confidence level).

Supplemental Vertical Accuracy (SVA) :

Urban Areas with Dense Man-Made Structures (using 24 checkpoints) - 20.1 cm at a 95 percent confidence level.

Tall Weeds and Crops (using 24 checkpoints) - 22.0 cm at a 95 percent confidence level.

Brushlands and Low Trees (using 23 checkpoints) - 25.4 cm at a 95 percent confidence level.

Forested Areas Fully Covered by Trees (using 20 checkpoints) - 30.0 cm at a 95 percent confidence level.

Consolidated Vertical Accuracy (using 115 checkpoints) - 24.1 cm at a 95 percent confidence level.

Completeness Report:

The lidar data is visually inspected for completeness to ensure that are no void areas or missing data.

Conceptual Consistency:

All formatted data cover the entire area specified for this project and are validated using a combination of commercial lidar processing software, GIS software, and proprietary programs to ensure proper formatting and loading prior to delivery.

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 were acquired and processed by Woolpert under contract to USGS. Data were found to have several issues during USGS quality assurance testing, but could not be found on USGS systems. A copy was obtained from the Alabama Department of Transportation in a different projection. Some of the issues found by USGS were addressed by NOAA, though not all.

Sources

Classified LAS

CC ID: 1145813
Contact Role Type: Originator
Contact Type: Organization
Contact Name: Alabama Department of Transportation

Lidar acquisition

CC ID: 1145814
Contact Role Type: Originator
Contact Type: Organization
Contact Name: Woolpert
Publish Date: 2014-12-22
Extent Type: Discrete
Extent Start Date/Time: 2014-01-07
Source Contribution:

This data set is the project specified acquired point cloud data.

Lidar deliverable processing

CC ID: 1145815
Contact Role Type: Originator
Contact Type: Organization
Contact Name: Woolpert
Publish Date: 2014-12-22
Extent Type: Discrete
Extent Start Date/Time: 2014-01-07
Source Contribution:

This data set is the project specified lidar deliverables.

Survey Control Acquistion

CC ID: 1145816
Contact Role Type: Originator
Contact Type: Organization
Contact Name: Woolpert
Publish Date: 2014-12-22
Extent Type: Discrete
Extent Start Date/Time: 2013-11-13
Source Contribution:

This data set is the project specified acquired ground control and QAQC control data.

Survey Control Acquistion

CC ID: 1145817
Contact Role Type: Originator
Contact Type: Organization
Contact Name: Magnolia River
Publish Date: 2014-12-22
Extent Type: Discrete
Extent Start Date/Time: 2014-01-24
Source Contribution:

This data set is the project specified acquired ground control and QAQC control data.

Process Steps

Process Step 1

CC ID: 1145818
Description:

Using one Leica ALS70 (lidar) and one Optech Gemini (lidar) system on board a Cessna 404 and Cessna 310 aircraft respectively, high density data, at a nominal pulse spacing (NPS) of 0.7 meters, were collected for this task order (approximately 7,400 square miles). Leica Specs- AGL = 1981 meters - Aircraft Speed = 150 Knots, Field of View (Full) = 40 degrees, Pulse Rate = 272 kHz, Scan Rate = 41.6 Hz, with an average side lap of 25%. Optech Specs- AGL = 1524 meters - Aircraft Speed = 130 Knots, Field of View (Full) = 24 degrees, Pulse Rate = 125 kHz, Scan Rate = 46 Hz, with an average side lap of 30%. Multiple returns were recorded for each laser pulse along with an intensity value for each return. Forty-one (41) missions were flown between January 7, 2014 and February 15, 2014. Twelve (12) Global Navigation Satellite System (GNSS) Base Stations were used in support of the lidar data acquisition. Specific information regarding latitude, longitude, and ellipsoid height to the L1 phase center is included in the lidar processing report. The geoid used to reduce satellite derived elevations to orthometric heights was GEOID12A. Data for the task order is referenced to the UTM Zone 16N, North American Datum of 1983 (2011), and NAVD88, in meters. Once the data acquisition and GPS processing phases are complete, the lidar data was processed immediately to verify the coverage had no voids. The GPS and IMU data was post processed using differential and Kalman filter algorithms to derive a best estimate of trajectory. The quality of the solution was verified to be consistent with the accuracy requirements of the project. The SBET was used to reduce the lidar slant range measurements to a raw reflective surface for each flight line. The coverage was classified to extract a bare earth digital elevation model (DEM) and separate last returns. The ALS70/Optech Gemini calibration and system performance is verified on a periodic basis using Woolpert's calibration range. The calibration range consists of a large building and runway. The edges of the building and control points along the runway have been located using conventional survey methods. Inertial measurement unit (IMU) misalignment angles and horizontal accuracy are calculated by comparing the position of the building edges between opposing flight lines. The scanner scale factor and vertical accuracy is calculated through comparison of lidar data against control points along the runway. Field calibration is performed on all flight lines to refine the IMU misalignment angles. IMU misalignment angles are calculated from the relative displacement of features within the overlap region of adjacent (and opposing) flight lines. The raw lidar data is reduced using the refined misalignment angles.

Process Date/Time: 2014-02-15 00:00:00

Process Step 2

CC ID: 1145819
Description:

Ground control and QAQC control point survey for the Mississippi AOI was performed by Woolpert surveyors, to support the USGS-NRCS Laurel MS 0.7m NPS Lidar project. All surveys were performed in such a way as to achieve ground control that supports lidar data at 9.25 cm RMSE accuracy and satisfy a local network accuracy of 5 cm at a 95% confidence level. All ground control survey field activities took place from 11/13/2013 thru 11/23/13. Woolpert collected control data for data processing as supplemental QAQC points. The supplemental QAQC points were collected to be used in independent accuracy testing. The field crew utilized Real-Time Kinematic (RTK) GPS surveying throughout most of the ground control data collection process. Using RTK GPS techniques, observations were performed on 26 ground control points and 161 quality control check points. The survey was conducted using a 1-second epoch rate, in a fixed solution RTK mode, with each observation lasting between 60 to 180 seconds. Each station was occupied twice to insure the necessary horizontal and vertical accuracies were being met for this photogrammetric project. In addition to the RTK GPS techniques, the project field crew utilized rapid-static (RS) GPS surveying techniques to establish RTK Base stations within areas lacking sufficient NGS control monument stations. Using Rapid-Static GPS techniques, observations were performed on one (2) RTK Base stations (110 & 111). The survey was conducted at a 5-second sync rate with each observation lasting between 40-360 minutes. All horizontal GPS control was based on UTM Zone 16N, NAD83 (2011) expressed in meters. The vertical datum used for this project was based on the North American Vertical Datum of 1988 (NAVD88), GEOID12A, also expressed in meters.

Process Date/Time: 2013-11-14 00:00:00

Process Step 3

CC ID: 1145820
Description:

Ground control and QAQC control point survey for the Alabama AOI was performed by Magnolia River surveyors, to support the USGS-NRCS Laurel MS 0.7m NPS Lidar project. All surveys were performed in such a way as to achieve ground control that supports lidar data at 9.25 cm RMSE accuracy and satisfy a local network accuracy of 5 cm at a 95% confidence level. All ground control survey field activities took place from 01/24/2014 thru 04/03/14. Magnolia River surveyors collected control data for data processing as supplemental QAQC points. The supplemental QAQC points were collected to be used in independent accuracy testing. The field crew utilized Real-Time Kinematic (RTK) GPS surveying utilizing the Alabama Departemnt of Transportation (ALDOT) Continually Operating Reference Station (CORS) network, via the internet using TCP/IP protocol and MiFi cellular connection. ALDOT provides single base corrections from the nearest operating GPS reference station. Using RTK GPS techniques, observations were performed on 21 ground control points and 115 quality control check points. The survey was conducted using a 1-second epoch rate, in a fixed solution RTK mode, with each observation lasting between 60 to 180 seconds. Each station was occupied twice to insure the necessary horizontal and vertical accuracies were being met for this photogrammetric project. A Sokkia Set330R3 total station in combination with a Trimble TSC3 data collector was used in areas where sufficient satellite coverage was not available for some quality control check points. All horizontal GPS control was based on UTM Zone 16N, NAD83 (2011) expressed in meters. The vertical datum used for this project was based on the North American Vertical Datum of 1988 (NAVD88), GEOID12A, also expressed in meters.

Process Date/Time: 2014-01-25 00:00:00

Process Step 4

CC ID: 1145821
Description:

The individual flight lines were inspected to ensure the systematic and residual errors have been identified and removed. Then, the flight lines were compared to adjacent flight lines for any mismatches to obtain a homogenous coverage throughout the project area. The point cloud underwent a classification process to determine bare-earth points and non-ground points utilizing "first and only" as well as "last of many" lidar returns. This process determined Default (Class 1), Ground (Class 2), Noise (Class 7), Water (Class 9), Ignored Ground (Class 10), Overlap Default (Class 17) and Overlap Ground (Class 18). The bare-earth (Class 2 - Ground) lidar points underwent a manual QA/QC step to verify the quality of the DEM as well as a peer-based QC review. This included a review of the DEM surface to remove artifacts and ensure topographic quality. Classification of water (class 9) and ignored ground (class 10) was completed via the use of the hydrologic breaklines collected for the hydro-flattening phase. The overlap classes were determined by first identifying the overlapping areas and reclassifying the LAS data by offset from a corridor. This allows the returns located on the edge of the swath to be removed from the bare earth coverage in an effort to produce a more uniform data density. The returns determined to be overlap are then further classified to produce overlap default (class 17) and overlap ground (class 18). The surveyed ground control points are used to make vertical adjustments to the data set and to perform the accuracy checks and statistical analysis of the lidar dataset. Supervisory QC monitoring of work in progress and completed editing ensured consistency of classification character and adherence to project requirements across the entire project area. The resulting deliverables for this task order consist of classified LAS file in LAS 1.2 format, Raw Swath LAS files in LAS 1.2 format, 1 meter pixel size DEM files in ERDAS IMG format, 1 meter pixel size 8-bit Intensity files in GeoTIFF format, and Hydrologic Breakline data in ESRI shape file format.

Process Date/Time: 2014-01-08 00:00:00

Process Step 5

CC ID: 1145822
Description:

The Alabama counties for the full data set were not found at the USGS National Map, nor could copies of the data be found. The Alabama Department of Transportation provided NOAA Office for Coastal Management a copy of the data for the two counties. These were received in proprietary *.zlas format. The data were converted to *.laz format using the LASliberator software (https://github.com/LASliberator/LASliberator). The data were in NAD83(2011) Alabama State Plane West (US survey ft) projection with vertical feet. This is different than the original UTM data and there was no record of the transformation. Several issues about the dataset were noted by USGS, including:

Global Encoding bit is set to 0 instead of 1

Point Misclassification (Buildings): 2 buildings remain present and are classified as ground.

Point Misclassification (Vegetation): Vegetation is systematically classified as bridges in the point cloud.

The global encoding bit was set to 1 using lasinfo. Class 17, with vegetation and bridge decks, was reset to class 1 (unclassified). The lasclassify program was run to classify vegetation and buildings. Any real bridge decks are now in the unclassified class. The two buildings classified as ground were not found or changed.

For ingest into the NOAA Data Access Viewer, the data were unprojected to geographic coordinates and the vertical component was converted to ellipsoid heights in meters by removing the GEOID12A model.

The global encoding bit was found to be incorrect (0 indicating GPS seconds of the week) and was changed to reflect adjusted GPS seconds.

Process Date/Time: 2021-04-02 00:00:00
Process Contact: NOAA Office for Coastal Management (NOAA/OCM)
Phone (Voice): (843) 740-1202
Email Address: coastal.info@noaa.gov
Source: Classified LAS

Catalog Details

Catalog Item ID: 64494
GUID: gov.noaa.nmfs.inport:64494
Metadata Record Created By: Kirk Waters
Metadata Record Created: 2021-04-02 20:00+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