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Short Citation:
OCM Partners, 2022: 2006 Texas Water Development Board (TWDB) Lidar: Aransas and Refugio Counties, https://www.fisheries.noaa.gov/inport/item/50033.

Item Identification

Title: 2006 Texas Water Development Board (TWDB) Lidar: Aransas and Refugio Counties
Short Name: tx2006_aransas_refugio_m96_metadata
Status: Completed
Publication Date: 2007-08
Abstract:

Using a LH Systems ALS50 Light Detection And Ranging (LiDAR) system, flight lines of standard density (1.4 meter ground

sample distance) data were collected over areas in Aransas and Refugio Counties, TX (approximately 282 square miles). Multiple

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

in 2006. The data was collected by Sanborn Mapping Company, Inc. for the Texas Water Development Board (TWDB)and the Federal

Emergency Management Agency (FEMA).

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:

10677

Supplemental Information:

The Aransas and Refugio 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 fair quality.

Again, no accuracy assessment was performed. The results of this review are detailed below. The results may also be viewed as

a formatted document. This document is entitled "Lidar Fact Sheet: Aransas and Refugio Counties," and may be viewed at:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/96/supplemental/aransas_refugio_fact-sheet.pdf

One aspect of the review included a bare earth point density review. A graphic was created for this pdf 6 that displays the bare earth

point density per 2500 sq meter cell and per sq meter. The issues determined in this part of the review were:

1. The areas offshore that have water points classified as bare earth. This can be seen in the amount of salmon colored

cells that occur offshore.

2. Also of note are the dark green cells that follow particular flightlines in the eastern part of the data set.

It appears that the points in these flightlines may have been classified differently than points in the rest of the data set.

This may be a result of data processing differences.

3. Red areas (low bare earth point density) correspond to vegetated/forested areas, as would be expected.

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

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/96/supplemental/2006_TWDB_Lidar_Aransas_and_Refugio_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 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: 687813
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: 687815
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: 687816
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: 687814
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: 1146648
W° Bound: -97.538724
E° Bound: -96.788924
N° Bound: 28.562486
S° Bound: 27.812486

Extent Group 1 / Time Frame 1

CC ID: 1146647
Time Frame Type: Range
Start: 2006-06-01
End: 2006-06-15

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: 742703
Download URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=96
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: 742704
Download URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/96/index.html
Distributor:
File Name: Bulk Download
Description:

Simple download of data files.

URLs

URL 1

CC ID: 742706
URL: https://coast.noaa.gov/dataviewer
URL Type:
Online Resource

URL 2

CC ID: 742707
URL: https://coast.noaa.gov
URL Type:
Online Resource

Activity Log

Activity Log 1

CC ID: 687839
Activity Date/Time: 2016-05-23
Description:

Date that the source FGDC record was last modified.

Activity Log 2

CC ID: 687838
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: 718639
Activity Date/Time: 2018-02-08
Description:

Partial upload of Positional Accuracy fields only.

Activity Log 4

CC ID: 742705
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

Vertical Positional Accuracy:

FEMA LiDAR Specifications; +/- 18 cm in open terrain

Completeness Report:

None

Conceptual Consistency:

None

Lineage

Process Steps

Process Step 1

CC ID: 1146639
Description:

Data Collection:

Using a LH Systems ALS50 Light Detection And Ranging (LiDAR) system, flight lines of standard density (1.4 meter ground

sample distance) data were collected over areas in Aransas and Refugio Counties, TX (approximately 282 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 June 1, 2006 and June 15, 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: 1146640
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:

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

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

Georgia.

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: 1146641
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: 1146642
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: 1146643
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: 1146644
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: 1146645
Description:

The NOAA Office for Coastal Management (OCM) received the files in las format. 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 Data Access Viewer (DAV):

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.

Process Date/Time: 2008-08-13 00:00:00

Catalog Details

Catalog Item ID: 50033
GUID: gov.noaa.nmfs.inport:50033
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