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Short Citation:
OCM Partners, 2022: 2006 Texas Water Development Board (TWDB) Lidar: Northern Cameron and Willacy Counties, https://www.fisheries.noaa.gov/inport/item/50032.

Item Identification

Title: 2006 Texas Water Development Board (TWDB) Lidar: Northern Cameron and Willacy Counties
Short Name: tx2005_cameron_willacy_m98_metadata
Status: Completed
Publication Date: 2007-08
Abstract:

Using a LH Systems ALS50 Light Detection And Ranging (LiDAR) system, standard density (1.4 meter ground sample distance) data were collected over areas in Northern Cameron and Willacy Counties, TX (approximately 1021 square miles). Multiple returns were recorded for each laser pulse along with an intensity value for each return. The data are bare earth classified. The data acquisition occurred in 36 missions between December 14, 2005 and February 23, 2006.

The data was collected by Sanborn Mapping Company, Inc. for the Texas Water Development Board (TWDB) and the Federal Emergency Management Agency (FEMA).

Data arrived at NOAA OCM (formerly CSC) with a number of tiles without classified ground points. This caused issues in the automated delivery of data through the Digital Coast. As a result, users would request ground points (because the data parameters included ground) in areas without this classification. This caused data errors. In order to improve the data use and eradicate errors in automation, a software known as lasground was used to classify unclassified points to ground. The new files were replaced on the internal servers and on the ftp server.

Original contact information:

Contact Name: Ryan Mitchell

Contact Org: Texas Natural Resources Information System (TNRIS)

Phone: 512-463-8337

Email: lidar@tnris.state.tx.us

Purpose:

This LIDAR operation was designed to provide a high density set of masspoints within the defined areas. The data

sets are suitable for the development of contours for use in hydraulic/hydrologic model development, and for assessing

environmental impacts. Typical uses for the data set include: FEMA Flood Plain Map Modernization, DFIRM map updates,

watersheds and other hydro studies per FEMA specifications, county mapping projects, and flood mitigation assessment.

Notes:

10676

Supplemental Information:

The Cameron and Willacy Counties data set was received from the Texas Water Development Board (TWDB). It was reviewed by the NOAA Office for Coastal Management at the macro level, which included checking for format and point characteristics for approximately 5% of the tiles. In addition, the entire data set was reviewed to establish that bare earth processing and proper classification of the points had been performed. It did not include accuracy or data processing (e.g. bare earth quality, flightline mismatch, feature removal) assessments. Based on the limited review, the data set on average appeared to be of poor quality.

This determination is based on the issues listed under the reviews below. Again, no accuracy assessment was performed.

The results may be viewed as a formatted document. This document is entitled "Lidar Fact Sheet: Cameron and Willacy Counties" and may be viewed at:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/98/supplemental/tx2006_twbd_cameron_willacy_m98_lidarfactsheet.pdf

A footprint for the project acquisition can be viewed here:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/98/supplemental/tx2006_twbd_cameron_willacy_m98.kmz

Tile Review

The Cameron and Willacy Counties lidar data do not cover the entire area of Cameron and Willacy, the southern portion of

Cameron County is not covered. The reviewed tiles had some formatting issues; the primary issues noted in this review are:

1. Lack of ground classification (#2) for much of the county. (See Figure 1 of the pdf)

2. Only single returns available

3. Water points remain, not classified

Bare Earth Point Density Review

The general lack of bare-earth classification can be seen in Figure 1 of the pdf. Much of Willacy County and the central

portion of Cameron County have not been classified so the bare earth covers only a portion of the area. This is an important

point-if requesting bare earth points-only a portion of the area will be returned. The barrier island does have ground

classifications, but no water removal.

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

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/98/supplemental/2006_TWDB_Lidar_Cameron_and_Willacy_Counties.kmz

Keywords

Theme Keywords

Thesaurus Keyword
ISO 19115 Topic Category
elevation
UNCONTROLLED
None Drainage Area
None Hydraulic
None Hydrographic
None Hydrology
None TNRIS (Texas Natural Resources Information System)

Physical Location

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

Data Set Information

Data Set Scope Code: Data Set
Maintenance Frequency: None Planned
Distribution Liability:

Any conclusions drawn from the analysis of this information are not the responsibility of the

Texas Water Development Board, the Texas Natural Resources Information System (TNRIS), the Sanborn Mapping Company,

the Office for Coastal Management, or its partners.

Data Set Credit: Data collected by Sanborn Mapping Company, Inc. for the Texas Water Development Board (TWDB) and the Federal Emergency Management Agency (FEMA). Acknowledgement of TNRIS (Texas Natural Resources Information System) would be appreciated in products derived and used from this data. Sanborn Mapping Company asks to be credited in derived products.

Support Roles

Data Steward

CC ID: 687771
Date Effective From: 2007-08
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: 687773
Date Effective From: 2007-08
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: 687774
Date Effective From: 2007-08
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: 687772
Date Effective From: 2007-08
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: Publication Date

Extent Group 1

Extent Group 1 / Geographic Area 1

CC ID: 1146680
W° Bound: -98.018265
E° Bound: -97.145144
N° Bound: 26.616343
S° Bound: 26.006739

Extent Group 1 / Time Frame 1

CC ID: 1146679
Time Frame Type: Range
Start: 2005-12-14
End: 2006-02-23

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: https://coast.noaa.gov/dataviewer;

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: 742698
Download URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=98
Distributor:
File Name: Customized Download
Description:

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

Distribution 2

CC ID: 742699
Download URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/98/index.html
Distributor:
File Name: Bulk Download
Description:

Simple download of data files.

URLs

URL 1

CC ID: 742701
URL: https://coast.noaa.gov/dataviewer
URL Type:
Online Resource

URL 2

CC ID: 742702
URL: https://coast.noaa.gov
URL Type:
Online Resource

Activity Log

Activity Log 1

CC ID: 687797
Activity Date/Time: 2016-05-23
Description:

Date that the source FGDC record was last modified.

Activity Log 2

CC ID: 687796
Activity Date/Time: 2017-11-14
Description:

Converted from FGDC Content Standards 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: 718638
Activity Date/Time: 2018-02-08
Description:

Partial upload of Positional Accuracy fields only.

Activity Log 4

CC ID: 742700
Activity Date/Time: 2018-03-13
Description:

Partial upload to move data access links to Distribution Info.

Technical Environment

Description:

Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.2.2.1350

Data Quality

Horizontal Positional Accuracy:

FEMA LiDAR Specifications; 1 m at 95% confidence level

Vertical Positional Accuracy:

FEMA LiDAR Specifications; +/- 18.5 cm RMSE in open terrain

Completeness Report:

None

Conceptual Consistency:

None

Lineage

Process Steps

Process Step 1

CC ID: 1146671
Description:

Data Collection:

Using a LH Systems ALS50 Light Detection And Ranging (LiDAR) system, standard density (1.4 meter ground sample distance)

data were collected over areas in Northern Cameron and Willacy Counties, TX (approximately 1021 square miles).

Multiple returns were recorded for each laser pulse along with an intensity value for each return. The data acquisition

occurred in missions between December 14, 2005 and February 23, 2006. During the LIDAR campaign, the Sanborn field crew

conducted a GPS field survey to establish final coordinates of the ground base stations for final processing of the

base-remote GPS solutions.

Process Date/Time: 2007-08-01 00:00:00

Process Step 2

CC ID: 1146672
Description:

Airborne GPS Processing:

Airborne GPS data was differentially processed and integrated with the post processed IMU data to derive a smoothed best

estimate of trajectory (SBET). The SBET was used to reduce the LiDAR slant range measurements to a raw reflective surface

for each flight line. The overlap between flight lines was removed to provide a homogeneous coverage, and the coverage was

classified to extract a bare earth digital elevation model (DEM).

Airborne GPS is differentially processed using the GrafNAV V7.50 software by Waypoint Consulting of Calgary, Alberta, Canada.

The PDOP and distance separation is as follows:

1. IMU data is processed using the PosPac V4.2 software by Applanix Corporation of Richmond Hill, Ontario, Canada.

2. The reflective surface is derived using the ALS Post Processor software by Leica Geosystems GIS & Mapping Division of Atlanta,

Georgia.

3. The classification and quality control (QC) of LiDAR data is carried out using TerraScan software by Terrasolid Limited of

Helsinki, Finland.

Process Date/Time: 2007-08-01 00:00:00

Process Step 3

CC ID: 1146673
Description:

IMU data Processing:

IMU data provides information concerning roll, pitch, and yaw of collection platform during collection event. IMU information

allows the pulse vector to be properly placed in 3D space allowing the distance from the aircraft reference point to be properly

positioned on the elevation model surface. IMU data is processed using the PosPac V4.2 software by Applanix Corporation of

Richmond Hill, Ontario, Canada.

Process Date/Time: 2007-08-01 00:00:00

Process Step 4

CC ID: 1146674
Description:

Reflective Surface Generation:

The reflective surface is derived using the ALS Post Processor software by Leica Geosystems GIS & Mapping Division of Atlanta,

Georgia.

Process Date/Time: 2007-08-01 00:00:00

Process Step 5

CC ID: 1146675
Description:

LIDAR Point Classification

The classification and quality control (QC) of LiDAR data is carried out using TerraScan software by Terrasolid Limited of

Helsinki, Finland.

Process Date/Time: 2007-08-01 00:00:00

Process Step 6

CC ID: 1146676
Description:

Output LAS Files

The product output of LiDAR data is carried out using TerraScan software by Terrasolid Limited of Helsinki, Finland. LAS Binary,

ascii xyz, and intensity images were created.

Process Date/Time: 2007-08-01 00:00:00

Process Step 7

CC ID: 1146677
Description:

The NOAA Office for Coastal Management (OCM) received the files in las format in July 2008. The files contained Lidar elevation and intensity measurements. The data was in UTM projection, and NAVD88 Geoid 03 vertical datum. OCM performed the following processing to the data to make it available within the Digital Coast:

1. The data were converted from UTM coordinates to geographic coordinates.

2. The data were converted from NAVD88 (orthometric) heights to GRS80 (ellipsoid) heights using Geoid 03.

3. The LAS data were sorted by latitude and the headers were updated.

NOAA OCM also performed a macro level review of this data set. This review involved checking for format and point characteristics in about 5% of the tiles. In addition, the entire data set was reviewed to establish that bare-earth processing and proper classification of the points had been performed. This review did not include accuracy or data-processing (e.g., bare-earth quality, flightline mismatch, feature removal) assessments. Please refer to the Supplemental Information above for more information about this review.

In August, 2015 effort were made to add more ground points to this project. For reference to which tiles had ground points prior to this process, please consult the lidar report provided in the Supplemental Information section. LasTools' lasground uses an algorithm to classify 'unclassified' points (only within tile that did not have classified ground points) to that particular 'ground' (Class 2).

Process Date/Time: 2015-08-31 00:00:00

Catalog Details

Catalog Item ID: 50032
GUID: gov.noaa.nmfs.inport:50032
Metadata Record Created By: Anne Ball
Metadata Record Created: 2017-11-15 15:23+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