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Short Citation:
OCM Partners, 2023: 2018 TWDB Lidar DEM: Coastal Texas, https://www.fisheries.noaa.gov/inport/item/57961.

Item Identification

Title: 2018 TWDB Lidar DEM: Coastal Texas
Short Name: tx2018_coastal_dem_m8899_metadata
Status: Completed
Publication Date: 2019-02-27
Abstract:

The Texas Water Development Board (TWDB) in cooperation with their project partners tasked Fugro Geospatial, Inc. (Fugro) under the Department of Information Resources (DIR) Geographic Information Systems (GIS) Hardware, Software and Services contract also known as the Texas Strategic Mapping (StratMap) Contract to acquire high resolution elevation data and associated products from airborne lidar systems during the 2017-2018 leaf-off season. The StratMap Program promotes inter-governmental collaboration and partnerships to purchase geospatial data products that provide cost savings and project efficiencies. Both the StratMap Program and the StratMap Contract are administered by the Texas Natural Resources Information System (TNRIS), a division of TWDB. Project partners include: Houston-Galveston Area Council (H-GAC), Harris County Flood Control District (HCFCD), and the United States Geological Survey (USGS). This Coastal Texas project consists of approximately 9,758 DO4Q tiles and is located on the Texas Coast covering much of Orange to Matagorda County along with Harris County and the surrounding area. The project includes large metropolitan areas as well as coastal areas. The Urban and Coastal AOIs consist of approximately 4.045 square miles and were acquired between January 12 and March 22, 2018 utilizing both Riegl LMS-Q680i and Riegl LMS-Q780 sensors; collecting multiple return x, y, and z as well as intensity data. Specialized in-house and commercial software processes the native lidar data into 3-dimensional positions that can be imported into GIS software for visualization and further analysis.

The NOAA Office for Coastal Management (OCM) downloaded this data set from this TNRIS site:

https://data.tnris.org/collection/b5bd2b96-8ba5-4dc6-ba88-d88133eb6643

These files were processed to the Data Access Viewer (DAV) and https. The total number of files downloaded and processed was 9071.

In addition to these bare earth Digital Elevation Model (DEM) data, the lidar point data that these DEM data were created from are also available. These data are available for custom download at the link provided in the URL section of this metadata record. Hydro breaklines are also available. These data are available for download 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:

Data products generated from this project will be used for floodplain management and planning, feature extraction, water quality modeling, stream restoration potential analysis, change detection and emergency management services and will be made available in the public domain through TNRIS.

Supplemental Information:

NA

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 Surface
None Terrain

Spatial Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Location Keywords
CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA > TEXAS
Global Change Master Directory (GCMD) Location Keywords
VERTICAL LOCATION > LAND SURFACE
UNCONTROLLED
Geographic Names Information System Harris County

Instrument Keywords

Thesaurus Keyword
UNCONTROLLED
Global Change Master Directory (GCMD) Instrument Keywords Earth Remote Sensing Instruments > Active Remote Sensing > Profilers/Sounders > Lidar/Laser Sounders > LIDAR > Light Detection and Ranging

Platform Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Platform Keywords
AIRCRAFT
Global Change Master Directory (GCMD) Platform Keywords
DEM > Digital Elevation Model

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:

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

Data Set Credit: Texas Water Development Board, Fugro Geospatial, Inc.

Support Roles

Data Steward

CC ID: 882678
Date Effective From: 2019
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: 882677
Date Effective From: 2019
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: 882679
Date Effective From: 2019
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: 882680
Date Effective From: 2019
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: 1153583
W° Bound: -96.609375
E° Bound: -93.687493
N° Bound: 31.03125
S° Bound: 28.59375

Extent Group 1 / Time Frame 1

CC ID: 1153571
Time Frame Type: Discrete
Start: 2018-03-03

Extent Group 1 / Time Frame 2

CC ID: 1153581
Time Frame Type: Discrete
Start: 2018-03-21

Extent Group 1 / Time Frame 3

CC ID: 1153582
Time Frame Type: Discrete
Start: 2018-03-22

Extent Group 1 / Time Frame 4

CC ID: 1153572
Time Frame Type: Discrete
Start: 2018-03-06

Extent Group 1 / Time Frame 5

CC ID: 1153573
Time Frame Type: Discrete
Start: 2018-03-07

Extent Group 1 / Time Frame 6

CC ID: 1153574
Time Frame Type: Discrete
Start: 2018-03-08

Extent Group 1 / Time Frame 7

CC ID: 1153575
Time Frame Type: Discrete
Start: 2018-03-11

Extent Group 1 / Time Frame 8

CC ID: 1153576
Time Frame Type: Discrete
Start: 2018-03-12

Extent Group 1 / Time Frame 9

CC ID: 1153577
Time Frame Type: Discrete
Start: 2018-03-13

Extent Group 1 / Time Frame 10

CC ID: 1153578
Time Frame Type: Discrete
Start: 2018-03-14

Extent Group 1 / Time Frame 11

CC ID: 1153579
Time Frame Type: Discrete
Start: 2018-03-19

Extent Group 1 / Time Frame 12

CC ID: 1153580
Time Frame Type: Discrete
Start: 2018-03-20

Extent Group 1 / Time Frame 13

CC ID: 1153551
Time Frame Type: Discrete
Start: 2018-01-13

Extent Group 1 / Time Frame 14

CC ID: 1153552
Time Frame Type: Discrete
Start: 2018-01-14

Extent Group 1 / Time Frame 15

CC ID: 1153553
Time Frame Type: Discrete
Start: 2018-01-15

Extent Group 1 / Time Frame 16

CC ID: 1153554
Time Frame Type: Discrete
Start: 2018-01-17

Extent Group 1 / Time Frame 17

CC ID: 1153555
Time Frame Type: Discrete
Start: 2018-01-18

Extent Group 1 / Time Frame 18

CC ID: 1153556
Time Frame Type: Discrete
Start: 2018-01-22

Extent Group 1 / Time Frame 19

CC ID: 1153557
Time Frame Type: Discrete
Start: 2018-01-23

Extent Group 1 / Time Frame 20

CC ID: 1153558
Time Frame Type: Discrete
Start: 2018-01-24

Extent Group 1 / Time Frame 21

CC ID: 1153559
Time Frame Type: Discrete
Start: 2018-01-25

Extent Group 1 / Time Frame 22

CC ID: 1153560
Time Frame Type: Discrete
Start: 2018-01-28

Extent Group 1 / Time Frame 23

CC ID: 1153561
Time Frame Type: Discrete
Start: 2018-01-29

Extent Group 1 / Time Frame 24

CC ID: 1153562
Time Frame Type: Discrete
Start: 2018-01-30

Extent Group 1 / Time Frame 25

CC ID: 1153563
Time Frame Type: Discrete
Start: 2018-01-31

Extent Group 1 / Time Frame 26

CC ID: 1153564
Time Frame Type: Discrete
Start: 2018-02-02

Extent Group 1 / Time Frame 27

CC ID: 1153565
Time Frame Type: Discrete
Start: 2018-02-08

Extent Group 1 / Time Frame 28

CC ID: 1153566
Time Frame Type: Discrete
Start: 2018-02-19

Extent Group 1 / Time Frame 29

CC ID: 1153567
Time Frame Type: Discrete
Start: 2018-02-23

Extent Group 1 / Time Frame 30

CC ID: 1153568
Time Frame Type: Discrete
Start: 2018-02-26

Extent Group 1 / Time Frame 31

CC ID: 1153569
Time Frame Type: Discrete
Start: 2018-03-01

Extent Group 1 / Time Frame 32

CC ID: 1153570
Time Frame Type: Discrete
Start: 2018-03-02

Spatial Information

Reference Systems

Reference System 1

CC ID: 1153549

Coordinate Reference System

CRS Type: Vertical
EPSG Code: EPSG:5703
EPSG Name: NAVD88 height
See Full Coordinate Reference System Information

Reference System 2

CC ID: 1153548

Coordinate Reference System

CRS Type: Projected
EPSG Code: EPSG:6344
EPSG Name: NAD83(2011) / UTM zone 15N
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: 882715
Start Date: 2019-10-15
End Date: Present
Download URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=8899
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2019 - Present)
File Name: Customized Download
Description:

Create custom data files by choosing data area, map projection, file format, etc. A new metadata will be produced to reflect your request using this record as a base.

File Type: Zip
Compression: Zip

Distribution 2

CC ID: 882716
Start Date: 2019-10-15
End Date: Present
Download URL: https://coast.noaa.gov/htdata/raster2/elevation/TX_Coastal_DEM_2018_8899
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2019 - Present)
File Name: Bulk Download
Description:

Bulk download of data files in the original coordinate system.

File Type: GeoTIFF

URLs

URL 1

CC ID: 882674
URL: https://coast.noaa.gov/
Name: NOAA's Office for Coastal Management (OCM) website
URL Type:
Online Resource
File Resource Format: HTML
Description:

Information on the NOAA Office for Coastal Management (OCM)

URL 2

CC ID: 882675
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 3

CC ID: 882847
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid12b/8898/supplemental/tx2018_coastal_m8898.kmz
Name: Browse Graphic
URL Type:
Browse Graphic
Description:

This graphic displays the footprint for this lidar data set.

URL 4

CC ID: 882848
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid12b/8898/supplemental/2018CoastalTexasLiDAR_FinalQAQCReport_20181221.pdf
Name: Data report
URL Type:
Online Resource
File Resource Format: pdf
Description:

Data report by AECOM.

URL 5

CC ID: 882849
URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=8898
URL Type:
Online Resource
Description:

Link to custom download, from the Data Access Viewer (DAV), the lidar point data from which these raster Digital Elevation Model (DEM) data were created.

URL 6

CC ID: 882850
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid12b/8898/breaklines/index.html
URL Type:
Online Resource
Description:

Link to the hydro breaklines.

Technical Environment

Description:

POSGNSS 5.2; POSPac 8.0; RiProcess 1.8.3; RiWorld 5.0.2; RiAnalyze 6.2; RiServer 1.99.5; Microstation 8.5.2.55 and MicroStation CONNECT 10.00.00.25; TerraScan 018.008; TerraModeler 018.002; Lasedit 1.36.01; GeoCue 2014.1.21.5; ArcMap 10.3; Global Mapper 17; ERDAS Imagine 2016; PhotoShop CS8; Fugro proprietary software; Windows 7 64-bit Operating System

\\triton\lidar\17004800_TNRIS_CoastalTX_Lidar\5_4_5_Delivery\Pilot\DEM_Raster

\\triton\lidar\17004800_TNRIS_CoastalTX_Lidar\5_4_5_Delivery\Pilot\Hydro_Flattened_Breaklines

\\triton\lidar\17004800_TNRIS_CoastalTX_Lidar\5_4_5_Delivery\Pilot\Intensity_Images\*.tif/tfw

\\triton\lidar\17004800_TNRIS_CoastalTX_Lidar\5_4_5_Delivery\Pilot\LAS_Point_Cloud\*.las

Data Quality

Horizontal Positional Accuracy:

Horizontal accuracy of LiDAR data will be achieved by identifying coincident locations between the Intensity rasters and the horizontal checkpoints. Deviations exhibited by the LiDAR Intensity rasters relative to the checkpoints were reported as an RMSE. RMSEr is 0.265 m.

Vertical Positional Accuracy:

AECOM followed the 2014 ASPRS Accuracy Standards for Digital Geospatial Data to compute the Non-vegetated Vertical Accuracy (NVA) RMSEz and Accuracyz at a 95% confidence interval (RMSEz*1.96) for checkpoints located in non-vegetated open terrain; the required NVA RMSEz is < 10 cm and the required NVA Accuracyz 95% is < 19.6 cm. AECOM utilized the 95th percentile method to determine the Vegetated Vertical Accuracy (VVA) for checkpoints located in vegetated terrain, regardless of vegetation type; the required VVA Accuracyz 95% is < 29.4 cm.

The NVA RMSEz of the DEM was calculated using independent checkpoints. Tested meters NVA of the DEM at a 95% confidence interval using independent checkpoints. Tested meters VVA of the DEM at a 95th percentile of the absolute value of vertical errors in all vegetated land cover categories combined using independent checkpoints.

Vertical accuracy of DEM raster data will be achieved by comparing the rasterized version of Class 2 Bare Earth points against the QA checkpoint elevation values. Deviations were reported as an RMSE and @ 95% confidence for NVA assessments and @ 95th Percentile for VVA assessments. Mimicking the checkpoints used as part of the LiDAR NVA checks 238 evenly distributed checkpoints were utilized to calculate the NVA RMSEz.

NVA RMSE is 4.796 cm

VVA RMSE is 6.21 cm

Completeness Report:

A complete iteration of processing (GPS/IMU Processing, Raw Lidar Data Processing, and Verification of Coverage and Data Quality) was performed to ensure that the acquired data was complete, uncorrupted, and that the entire project area had been covered without gaps between flight lines. A sensor anomaly caused a few small areas of voids within tile stratmap17-50cm-2996134a1. The Classified Point Cloud data files include all data points collected except the ones from Cross ties and Calibration lines. The points that have been removed or excluded are the points fall outside the project delivery boundary. Points are classified. A visual qualitative assessment was performed to ensure data completeness. The Intensity Image files cover the entire project delivery boundary. A visual qualitative assessment was performed to ensure data completeness. The Intensity Image product is of good quality. The Hydro Breaklines cover the entire project delivery boundary and extend beyond the boundary in a few locations. A visual qualitative assessment was performed to ensure data completeness. No void areas or missing data exist. The Hydro Breakline product is of good quality. The DEM raster files cover the entire project delivery boundary. A visual qualitative assessment was performed to ensure data completeness.

Conceptual Consistency:

Compliance with the accuracy standard was ensured by the collection of ground control and the establishment of GPS base stations in the project area. The following checks were performed: 1) The lidar data accuracy was validated by performing a full boresight adjustment and then checking it against the ground control prior to generating a digital terrain model (DTM) or other products. 2) Lidar elevation data was validated through an inspection of edge matching and visual inspection for quality (artifact removal). The following software was used for the validation: 1) RiProcess 1.8.3, RiWorld 5.0.2, RiAnalyze 6.2, RiServer 1.99.5) Fugro proprietary software; 20170530.

Lineage

Lineage Statement:

Fugro collected Light Detection and Ranging (LIDAR) data in the coastal upper Texas project area for the Texas Water Development Board (TWDB) and TNRIS.

NOAA OCM downloaded the data from TNRIS and ingested it into the Digital Coast Data Access Viewer for distribution.

Sources

Coastal Texas; Ground Control Survey Report

CC ID: 1153541
Publish Date: 2018-04-06
Extent Type: Range
Extent Start Date/Time: 2018-01-24
Extent End Date/Time: 2018-03-16
Source Contribution:

All surveying activities were performed by Fugro USA Land, Inc. A total of ground control points to support the lidar collection were collected in the Urban and Coastal AOIs; the points were a combination of gravel, dirt, asphalt, and concrete all in open terrain. The horizontal Datum was the North American Datum of 1983 (NAD83, 2011). The vertical datum was the North American Datum of 1988 (NAVD88). The geoid model, GEOID12B, was used to obtain the NAVD88 orthometric heights from the GRS 1980 ellipsoidal heights.

Coastal TX;Urban and Coastal AOIs Aerial Acquisition

CC ID: 1153540
Publish Date: 2018-12-17
Source Contribution:

Fugro collected Riegl-derived lidar over the Coastal Texas project AOI with a 0.5 meter Nominal Pulse Spacing (NPS). Data was collected when environmental conditions met the specified criteria: leaf-off and no significant snow cover or flood conditions; cloud, smoke, dust, and fog-free between the aircraft and ground. The collection for the Urban and Coastal AOIs was accomplished on January 13, 14, 15, 17, 18, 22, 23, 24, 25, 28, 29, 30, and 31, February 2, 8, 19, 23, and 26, and March 1, 2, 3, 6, 7, 8, 11, 12, 13, 14, 19, 20, 21, and 22 2018; 982 flight lines were acquired in 117 lifts. The lines were flown at an average of 3,250 feet above mean terrain. The collection was performed using the Riegl LMS-Q680i and Riegl LMS-Q780i lidar systems, serial numbers 163, 165, 421, and 961.

Process Steps

Process Step 1

CC ID: 1153542
Description:

All acquired lidar data went through a preliminary review to assure that complete coverage had been obtained and that there were no gaps between flight lines before the flight crew left the project site. Once back in the office, the data was run through a complete iteration of processing to ensure that it is complete, uncorrupted, and that the entire project area has been covered without gaps between flight lines. There are essentially three steps to this processing: 1) GPS/IMU Processing - Airborne GPS and IMU data was processed using the airport GPS base station data. 2) Raw Lidar Data Processing - Technicians processed the raw data to LAS format flight lines with full resolution output before performing QC. A starting configuration file is used in this process, which contains the latest calibration parameters for the sensor. The technicians also generated flight line trajectories for each of the flight lines during this process. 3) Verification of Coverage and Data Quality - Technicians checked the trajectory files to ensure completeness of acquisition for the flight lines, calibration lines, and cross flight lines. The intensity images were generated for the entire lift at the required 0.5 meter NPS. Visual checks of the intensity images against the project boundary were performed to ensure full coverage to the 300 meter buffer beyond the project boundary. The intensity histogram was analyzed to ensure the quality of the intensity values. The technician also thoroughly reviewed the data for any gaps in project area. The technician generated a sample TIN surface to ensure no anomalies were present in the data. Turbulence was inspected for each flight line; if any adverse quality issues were discovered, the flight line was rejected and re-flown. The technician also evaluated the achieved post spacing against project specified 0.5 meter NPS as well as making sure no clustering in point distribution.

Process Date/Time: 2018-04-01 00:00:00

Process Step 2

CC ID: 1153543
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 Fugro proprietary and commercial software to calculate initial boresight adjustment angles based on sample areas within 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 the matching between flight line overlaps 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 ? 3 cm RMSDz within swath overlap (between adjacent swaths) with a maximum difference of ± 17 cm. 5) The technicians ran a final vertical accuracy check of the boresighted flight lines against the surveyed ground control points after the z correction to ensure the requirement of RMSEz (non-vegetated) ? 10 cm, NVA ? 19.6 cm 95% Confidence Level was met.

Process Date/Time: 2018-05-11 00:00:00

Process Step 3

CC ID: 1153544
Description:

Once boresighting was completed, the project was set up for automatic classification. First, the lidar data was cut into production tiles and the flight line overlap points, noise points, ground points, and building points were classified automatically. Fugro utilized commercial software, as well as proprietary, in-house developed software for automatic filtering. The parameters used in the process were customized for each terrain type to obtain optimum results. These parameters were also customized to capture multiple categories of vegetation based on height (low, medium, and high vegetation). After all “low” points are classified, points remaining are reclassified automatically based on height from the ground. Once the automated filtering was completed, the files were run through a visual inspection to ensure that the filtering was not too aggressive or not aggressive enough. In cases where the filtering was too aggressive and important terrain were filtered out, the data was either run through a different filter within local area or was corrected during the manual filtering process. Bridge deck points and culvert points were classified as well during the interactive editing process. Interactive editing was completed in visualization software that provides manual and automatic point classification tools. Fugro utilized commercial and proprietary software for this process. All manually inspected tiles went through a peer review to ensure proper editing and consistency. After the manual editing and peer review, all tiles went through another final automated classification routine. This process ensures only the required classifications are used in the final product (all points classified into any temporary classes during manual editing will be re-classified into the project specified classifications). Once manual inspection, QC and final autofilter is complete for the lidar tiles, the LAS data was packaged to the project specified tiling scheme, cut to the approved tile layout, and formatted to LAS v1.4. It was also re-projected to UTM Zone 15 north; NAD83(2011), meters; NAVD88(GEOID12B), meters. The file header was formatted to meet the project specification. This Classified Point Cloud product was used for the generation of derived products. This product was delivered in fully compliant LAS v1.4, Point Record Format 6 with Adjusted Standard GPS Time. Georeferencing information is included in all LAS file headers. Each tile has File Source ID assigned to zero. The Point Source ID matches to the flight line ID in the flight trajectory files. Intensity values are included for each point, normalized to 16-bit. The following classifications are included: Class 1 – Processed, but unclassified; Class 2 – Bare earth ground; Class 3 – Low Vegetation (0.01m to 1.00m above ground); Class 4 – Medium Vegetation (1.01m to 3.00m above ground); Class 5 – High Vegetation (greater than 3.01m above ground); Class 6 – Building; Class 7 – Low Point (Noise); Class 9 – Water; Class 10 – Ignored Ground; Class 14 – Culverts; and Class 17 – Bridge Decks. The classified point cloud data was delivered in tiles without overlap using the project tiling scheme.

Process Date/Time: 2018-05-29 00:00:00

Process Step 4

CC ID: 1153545
Description:

Hydro linework is produced by heads-up digitizing using classified lidar datasets. Additionally, products created from lidar including intensity images, shaded-relief TIN surfaces, and contours are used. Hydrographic features were collected as separate feature classes: 1) Inland Ponds and Lakes nominally larger than 2 acres in area (Ponds_and_Lakes) and 2) Inland Streams and Rivers nominally larger than 15.25 meters (Stream_and_River)(1_Acre_Islands). After initial collection, features were combined into working regions based on watershed sub-basins. Linework was then checked for the following topological and attribution rules: 1) Lines must be attributed with the correct feature code and 2) Lake and stream banklines must form closed polygons. Hydro features were collected as vector linework using lidar and its derived products listed above. This linework is initially 2D, meaning that it does not have elevation values assigned to individual line vertices. Vertex elevation values were assigned using a distance weighted distribution of lidar points closest to each vertex. This is similar to draping the 2D linework to a surface modeled from the lidar points. After the initial ‘drape’, the linework elevation values were further adjusted based on the following rules: 1) Lake feature vertices were re-assigned (flattened) to lowest draped vertex value, and 2) Double stream bankline vertices were re-assigned based on the vertices of the closest adjusted double stream connector line. Fugro proprietary software was used to create profiles to ensure bank to bank flatness, monotonicity check, and lake flatness. The hydro breaklines were delivered as polygons in Esri ArcGIS version 10.3 geodatabase format.

Process Date/Time: 2018-05-30 00:00:00

Process Step 5

CC ID: 1153546
Description:

The hydro-flattened bare earth DEM was generated using the lidar bare earth points and 3D hydro breaklines to a resolution of 1 meter. The bare earth points that fell within 1*NPS along the hydro breaklines (points in class 10) were excluded from the DEM generation process. This is analogous to the removal of mass points for the same reason in a traditional photogrammetrically compiled DTM. This process was done in batch using proprietary software. The technicians then used Fugro proprietary software for the production of the lidar-derived hydro-flattened bare earth DEM surface in initial grid format at 1 meter GSD. Water bodies (inland ponds and lakes), inland streams and rivers, and island holes were hydro-flattened within the DEM. Hydro-flattening was applied to all water impoundments, natural or man-made, nominally larger than 2 acres in area and to all streams nominally wider than 15.25 meters. This process was done in batch. Once the initial, hydro-flattened bare earth DEM was generated, the technicians checked the tiles to ensure that the grid spacing met specifications. The technicians also checked the surface to ensure proper hydro-flattening. The entire data set was checked for complete project coverage. Once the data was checked, the tiles were then converted to .IMG format. Georeference information is included in the raster files.

Process Date/Time: 2018-06-01 00:00:00

Process Step 6

CC ID: 1153547
Description:

The NOAA Office for Coastal Management (OCM) downloaded 9071 raster DEM files in img format from TNRIS at this site: https://data.tnris.org/collection/b5bd2b96-8ba5-4dc6-ba88-d88133eb6643. The data were in UTM14 (913 files) and UTM15 (8158 files) NAD83(2011), meters coordinates and NAVD88 (Geoid12b) elevations in meters. The bare earth raster files were at a 1 meter grid spacing.

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

1. Used internal script to assign the EPSG codes and convert to GeoTiff format.

2. Copied to the files to https.

Process Date/Time: 2019-10-15 00:00:00
Process Contact: Office for Coastal Management (OCM)

Related Items

Item Type Relationship Type Title
Data Set (DS) Cross Reference 2018 TWDB Lidar: Coastal Texas

Catalog Details

Catalog Item ID: 57961
GUID: gov.noaa.nmfs.inport:57961
Metadata Record Created By: Rebecca Mataosky
Metadata Record Created: 2019-10-15 14:25+0000
Metadata Record Last Modified By: SysAdmin InPortAdmin
Metadata Record Last Modified: 2022-08-09 17:11+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