Short Citation:
Office for Coastal Management, 2021: 2014 Lidar DEM; Horry County SC, https://www.fisheries.noaa.gov/inport/item/57194.

Item Identification

Title: 2014 Lidar DEM; Horry County SC
Status: Completed
Publication Date: 2016-01-15
Abstract:

This data set is comprised of a hydro-flattened digital elevation model (DEM). The total area collected for Horry County, SC for this project is approximately 1092 square miles. Lidar data was collected and processed to meet the requirements of the project task order. The lidar collection was a collaborative effort between two data acquisition firms. While Woolpert was responsible for collection of the majority of the county, the coastal portion of the data was collected by Quantum Geospatial and is detailed in the processing steps of the metadata. Lidar data is a remotely sensed high resolution elevation data collected by an airborne platform. 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, four (4) foot pixel raster DEMs of the bare-earth surface in ERDAS IMG Format. Each LAS file contains lidar point information, which has been calibrated, controlled, and classified. Ground conditions: Water at normal levels; no unusual inundation; no snow. The bare earth DEMs along the coast may have a variance in the water heights due to temporal differences during the lidar data acquisition and will be represented in DEM as a seam-like anomaly. One coastal elevation was applied to entire project area. Due to differing acquisition dates and thus differing tide levels there will be areas in the DEM exhibiting what appears to be "digging" water features. Sometimes as much as approximately 2.5 feet. This was done to ensure that no coastal hydro feature was "floating" above ground surface. This coastal elevation will also affect connected river features wherein a sudden increase in flow will be observed in the DEM to accommodate the coastal elevation value. During Hydrologic breakline collection, Woolpert excluded obvious above-water piers or pier-like structures from the breakline placement. Some features extend beyond the apparent coastline and are constructed in a manner that can be considered an extension of the ground. These features were treated as ground during classification and subsequent hydrologic delineation. In all cases, professional practice was applied to delineate what appeared to be the coast based on data from multiple sources; Due to the many substructures and the complexity of the urban environment, interpolation and apparent "divots" (caused by tinning) may be evident in the surface of the bare earth DEM. In all cases, professional practice was applied to best represent the topography.

The data received by the NOAA OCM are topographic data in LAS 1.2 format, classified as unclassified (1), ground (2), all noise (7), water (9), ignored ground (10), overlap unclassified (17), and overlap ground (18). Digital Elevation Models (DEMs) and breakline data are also available.

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

Original contact information:

Contact Org: Woolpert

Phone: (937) 461-5660

Purpose:

The lidar data were acquired and processed under the requirements identified in this task order. The data produced for this AOI is intended to support the local Coastal Zone Managers in their decision making processes. This data will be used for coastal management applications.

Keywords

Theme Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Science Keywords Earth Science > Land Surface > Topography > Terrain Elevation > Topographical Relief Maps
Global Change Master Directory (GCMD) Science Keywords Earth Science > Oceans > Coastal Processes > Coastal Elevation
ISO 19115 Topic Category elevation
None Classified LAS 1.2
None lidar
None Topography

Spatial Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Location Keywords Continent > North America > United States Of America > South Carolina
None Horry County
None South Carolina
None United States

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
Distribution Liability:

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

Support Roles

Data Steward

CC ID: 868107
Date Effective From: 2016-01-15
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: 868109
Date Effective From: 2016-01-15
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: 868110
Date Effective From: 2016-01-15
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: 868108
Date Effective From: 2016-01-15
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: 868142
W° Bound: -79.350005
E° Bound: -78.551698
N° Bound: 34.308899
S° Bound: 33.552285

Extent Group 1 / Time Frame 1

CC ID: 868192
Time Frame Type: Range
Start: 2014-02-22
End: 2014-02-25
Description:

Non-coastal portion of data collected during this time.

Extent Group 1 / Time Frame 2

CC ID: 868138
Time Frame Type: Range
Start: 2014-01-22
End: 2014-01-26
Description:

Coastal portion of the data collected during this time.

Access Information

Security Class: Unclassified
Data Access Procedure:

This data can be obtained on-line at the following URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=4814 The data set is dynamically generated based on user-specified parameters.;

Data Access Constraints:

None

Data Use Constraints:

None, however, users should be aware that temporal changes may have occurred since this dataset was collected and that some parts of these data may no longer represent actual surface conditions. Users should not use these data for critical applications without a full awareness of its limitations.

Distribution Information

Distribution 1

CC ID: 868111
Download URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=4814
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2016-01-15 - Present)
File Name: Customized Download
Description:

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

File Type: Zip

Distribution 2

CC ID: 868112
Download URL: https://coast.noaa.gov/htdata/lidar1_z/geoid12b/data/4814
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2016-01-15 - Present)
File Name: Bulk Download
Description:

Simple download of data files.

File Type: GeoTIFF

URLs

URL 1

CC ID: 868113
URL: https://coast.noaa.gov/dataviewer
URL Type:
Online Resource

URL 2

CC ID: 868114
URL: https://coast.noaa.gov
URL Type:
Online Resource

URL 3

CC ID: 868115
URL: https://coast.noaa.gov/htdata/lidar1_z/geoid12b/data/4814/supplemental/sc2014_horry_m4814.kmz
Name: Browse Graphic
URL Type:
Browse Graphic
File Resource Format: kmz
Description:

This graphic shows the lidar footprint for the 2014 Horry County, South Carolina lidar project.

URL 4

CC ID: 868193
URL: https://coast.noaa.gov/htdata/lidar1_z/geoid12b/data/4814/breaklines/index.html
Name: Breakline Data
URL Type:
Online Resource
Description:

Breakline Data

URL 5

CC ID: 868194
URL: https://coast.noaa.gov/htdata/lidar1_z/geoid12b/data/4814/supplemental/sc2014_horry_m4814_lidar_report.pdf
Name: Lidar Delivery Report
URL Type:
Online Resource

URL 6

CC ID: 868195
URL: https://coast.noaa.gov/htdata/lidar1_z/geoid12b/data/4814/supplemental/sc2014_horry_m4814_survey_report.pdf
Name: Survey Report
URL Type:
Online Resource

Activity Log

Activity Log 1

CC ID: 868117
Activity Date/Time: 2016-09-14
Description:

Date that the source FGDC record was last modified.

Activity Log 2

CC ID: 868116
Activity Date/Time: 2017-11-14
Description:

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

Activity Log 3

CC ID: 868118
Activity Date/Time: 2018-02-08
Description:

Partial upload of Positional Accuracy fields only.

Activity Log 4

CC ID: 868119
Activity Date/Time: 2018-03-13
Description:

Partial upload to move data access links to Distribution Info.

Data Quality

Horizontal Positional Accuracy:

Compiled to meet 0.359 meters horizontal accuracy at 95 percent confidence level.; Quantitative Value: 0.359 meters, Test that produced the value: Lidar system specifications are available in the project report

Vertical Positional Accuracy:

Raw LAS Swath Fundamental Vertical Accuracy (FVA) Tested 0.397 ft (4.764 inches) fundamental vertical accuracy at 95 percent confidence level, derived according to NSSDA, in open terrain in open using (RMSEz) 0.203 x 1.9600, tested against the TIN against all points. RMSEz = 6.2 cm

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.

Lineage

Sources

Flightline Vectors

CC ID: 868128
Contact Name: Woolpert
Publish Date: 2015-01-31
Extent Type: Discrete
Extent Start Date/Time: 2014-02-26
Source Contribution:

This data set is the project specified flightline vector data. | Type of Source Media: Vector dataset

Hydrologic breakline deliverable processing

CC ID: 868126
Contact Name: Woolpert
Publish Date: 2015-01-31
Extent Type: Discrete
Extent Start Date/Time: 2014-02-23
Source Contribution:

This data set is the project specified hydrologic breakline deliverable. | Type of Source Media: 3-d breakline dataset

Lidar acquisition

CC ID: 868122
Contact Name: Woolpert
Publish Date: 2015-01-31
Extent Type: Discrete
Extent Start Date/Time: 2014-02-22
Source Contribution:

This data set is the project specified acquired point cloud data. | Type of Source Media: Lidar dataset

Lidar acquisition

CC ID: 868123
Contact Name: Quantum Geospatial
Publish Date: 2015-01-31
Extent Type: Discrete
Extent Start Date/Time: 2014-01-22
Source Contribution:

This data set is the project specified acquired point cloud data. | Type of Source Media: Lidar dataset

Lidar deliverable processing

CC ID: 868125
Contact Name: Woolpert
Publish Date: 2015-01-31
Extent Type: Discrete
Extent Start Date/Time: 2014-02-23
Source Contribution:

This data set is the project specified lidar deliverables. | Type of Source Media: Lidar dataset

Survey Control Acquisition

CC ID: 868124
Contact Name: Woolpert
Publish Date: 2015-01-31
Extent Type: Discrete
Extent Start Date/Time: 2014-03-18
Source Contribution:

This data set is the project specified acquired ground control and QAQC control data. | Type of Source Media: Control dataset

Tile index and data extent

CC ID: 868127
Contact Name: Woolpert
Publish Date: 2015-01-31
Extent Type: Discrete
Extent Start Date/Time: 2014-02-23
Source Contribution:

This data set is the project specified tile index and data extent. | Type of Source Media: vector dataset

Process Steps

Process Step 1

CC ID: 868129
Description:

Using one Leica ALS70 (lidar) system on board a Cessna 404 Titan fixed-wing aircraft, lidar data, at a nominal pulse spacing (NPS) of 0.7 meters, was collected for this task order (approximately 1092 square miles). AGL = 6500 feet - Aircraft Speed = 150 Knots, Field of View (Full) = 40 degrees, Pulse Rate = 272.0 kHz, Scan Rate = 42.3 Hz, with an average side lap of 28.7%. Multiple returns were recorded for each laser pulse along with an intensity value for each return. Five (5) missions were flown between February 22, 2014 and February 25, 2014. One (1) Global Navigation Satellite System (GNSS) Base Station was 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. Multiple returns were recorded for each laser pulse along with an intensity value for each return. The lidar data acquisition parameters for this mission are detailed in the lidar processing report for this task order. For all acquired lidar data as part of entire Horry County Elevation Data and Imagery task order, the geoid used to reduce satellite derived elevations to orthometric heights was GEOID12A. Data for the task order is referenced to the StatePlane Zone of South Carolina, North American Datum of 1983 (2011) International Feet, and NAVD88, in International Feet. 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 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: 2014-02-23 00:00:00

Process Step 2

CC ID: 868130
Description:

Using one Leica ALS50 (lidar) system on board a Cessna 208B fixed-wing aircraft, lidar data, at a nominal pulse spacing (NPS) of 0.3 meters, was collected for the coastal portion of the Horry County AOI. AGL = 1968 feet - Aircraft Speed = 110 Knots, Field of View (Full) = 40 degrees, Pulse Rate = 130.0 kHz, Scan Rate = 42.9 Hz, with an average side lap of 50%. Multiple returns were recorded for each laser pulse along with an intensity value for each return. The collection occurred on two dates: January 22, 2014 and January 26, 2014. The absolute accuracy of the coastal data set was tested by Quantum Geospatial prior to delivery to Woolpert for inclusion to the overall Horry County dataset yielding a result of 2.9 cm RMSEz. The coastal data set was assessed for data coverage, GPS and IMU quality, collection density, and calibration quality by Woolpert prior to merging with the Woolpert collected data for the remainder of the county. Final project accuracy statistical analysis was performed on the merged county and coastal dataset. For all acquired lidar data as part of entire Horry County Elevation Data and Imagery task order, the geoid used to reduce satellite derived elevations to orthometric heights was GEOID12A. Data for the task order is referenced to the State Plane Zone of South Carolina, North American Datum of 1983 (2011) International Feet, and NAVD88, in International Feet. 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.

Process Date/Time: 2014-02-23 00:00:00

Process Step 3

CC ID: 868131
Description:

Ground control and QAQC control point survey was performed by Woolpert surveyors, to support the NOAA Horry County Elevation Data and Imagery 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 03/18/2014 through 03/22/14. 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 survey was performed using one (1) Trimble Navigation R8 Model 3 GNSS dual frequency GPS receiver with Air Link Communications Raven CDMA cellular modem, one (1) Trimble Navigation R8 Model 2 receiver, one (1) Trimble Navigation R8 receiver, and one (1) Trimble Navigation R8 Model 3 GNSS dual frequency GPS receiver with Air Link Communications Raven CDMA cellular modem as a rover. Woolpert surveyors,utilizing Real-Time Kinematic GPS techniques, made observations on 27 ground control points and 21 quality control check points using 1-second epoch rates and observations of 60 to 180 seconds. Each station was occupied twice to insure necessary horizontal and vertical accuracies. All GPS ground control observations were processed using Trimble Navigation's Trimble Business Center. All horizontal GPS control was based on South Carolina State Plane Zone (3900), NAD83(2011) expressed in International Feet. The vertical datum used for this project was based on the North American Vertical Datum of 1988 (NAVD88), GEOID12A, also expressed in International Feet.

Process Date/Time: 2014-03-19 00:00:00

Process Step 4

CC ID: 868132
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 homogeneous 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, 4 feet pixel size DEM files in ERDAS IMG format, and Hydrologic Breakline, Flightline Vector, and Control Point data in ESRI Geodatabase format.

Process Date/Time: 2014-02-23 00:00:00

Process Step 5

CC ID: 868133
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 homogeneous 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 hydrologic breaklines were produced according to USGSv1.0 specifications. The compilation procedure included use of lidar intensity, bare earth surface model, point cloud data, open source imagery in an effort to manually compile hydrologic features in a 2-d environment. Following the compilation phase, a separate process was used to adjust the breakline data to best match the water level at the time of the lidar collection. Any ponds and/or lakes were adjusted to be at or just below the bank and to be at a constant elevation. Any streams were adjusted to be at or just below the bank and to be monotonic. Manual QAQC and peer-based QC review was performed on all delineated data to ensure horizontal placement quality and on all adjusted data to ensure vertical placement quality. The final hydrologic breakline product was delivered in ESRI Geodatabase format and was also used in the processing of the DEM deliverable. The resulting deliverables for this task order consist of classified LAS file in LAS 1.2 format, 4 feet pixel size DEM files in ERDAS IMG format, and Hydrologic Breakline, Flightline Vector, and Control Point data in ESRI Geodatabase format.

Process Date/Time: 2014-02-23 00:00:00

Process Step 6

CC ID: 868134
Description:

Tile Size: 5,000ft x 5,000ft. The tile file name was derived from the southwest corner of each tile. Project data extent was provided by NOAA and subsequently buffered by 1 kilometer and provided in shape file format. Project deliverables were clipped to the 1 kilometer data extent.

Process Date/Time: 2014-02-23 00:00:00

Process Step 7

CC ID: 868135
Description:

The flightline vectors were generated by importing the Raw LAS strips into Geocue software. Bounding polygons are created around each individual swath. The polygons were exported to shapefile and a centerline was generated for each. Attribution was added to each flightline in the form of line number, date of acquisition, and start/stop times.

Process Date/Time: 2014-02-26 00:00:00

Process Step 8

CC ID: 868136
Description:

The NOAA Office for Coastal Management (OCM) received 1488 files in .img format from Woolpert. The files contained hydroflattened DEM data. The data were in State Plane South Carolina FIPS 3900 NAD 1983 (2011) Intl Ft coordinates and North American Vertical Datum of 1988 (GEOID12A) Intl Ft heights. OCM performed the following processing:

1. IMG files were converted to tif format using gdal_translate.

2. The raster files were copied to database and https for Digital Coast storage and provisioning purposes

Process Date/Time: 2015-02-04 00:00:00
Process Contact: Office for Coastal Management (OCM)

Related Items

Item Type Relationship Type Title
Data Set (DS) Cross Reference 2014 Horry County, South Carolina Lidar

Lidar Points Mission

Catalog Details

Catalog Item ID: 57194
Metadata Record Created By: Blake Waring
Metadata Record Created: 2019-08-12 15:54+0000
Metadata Record Last Modified By: Brianna Key
Metadata Record Last Modified: 2020-12-11 16:32+0000
Metadata Record Published: 2020-12-11
Owner Org: OCM
Metadata Publication Status: Published Externally
Do Not Publish?: N
Metadata Next Review Date: 2021-12-12