50035
2006 Texas Water Development Board (TWDB) Lidar: Calhoun County
tx2006_calhoun_m97_metadata
Data Set
Published / External
49401
Lidar - partner (no harvest)
Project
Completed
2007-08
Using a LH Systems ALS50 Light Detection And Ranging (LiDAR) system, 64 flight lines of standard density (1.4 meter ground
sample distance) data were collected over areas in Calhoun County, TX (approximately 545 square miles). Multiple returns
were recorded for each laser pulse along with an intensity value for each return. The data acquisition occurred in 7 missions
between June 26, 2006 and June 28, 2006 and another collection between July 12, 2006 and July 15, 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 Water Development Board
Phone: 512-463-8337
Email: lidar@tnris.state.tx.us
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.
10679
The Calhoun County 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: Calhoun County, Texas" and may be viewed at:
https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/97/supplemental/CalhounCounty_factsheet.pdf
One aspect of the review included a bare earth point density review. A graphic was created for this pdf 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. There is a distinct difference between the northeastern portion of the county and the main portion of the county
in terms of ground point densities; the northeastern portion has a consistently higher density.
2. There are also some lower density tiles in the central-northern portion of the county that indicate some tile specific
processing.
3. The striping in water clearly indicates a lack of water classification. Additionally, at the time of the review, there
were a few missing and corrupt tiles.
A footprint of this data set may be viewed in Google Earth at:
https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/97/supplemental/2006_TWDB_Lidar_Calhoun_County.kmz
Theme
ISO 19115 Topic Category
elevation
Theme
Drainage Area
Theme
Hydraulic
Theme
Hydrographic
Theme
Hydrology
Theme
TNRIS (Texas Natural Resources Information System)
Office for Coastal Management
Charleston
SC
Data Set
None Planned
Any conclusions drawn from the analysis of this information are not the responsibility of the Office for Coastal Management or its partners.
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.
Data Steward
2007-08
Organization
NOAA Office for Coastal Management
NOAA/OCM
coastal.info@noaa.gov
2234 South Hobson Ave
Charleston
SC
29405-2413
(843) 740-1202
https://coast.noaa.gov
NOAA Office for Coastal Management Home Page
Online Resource
Distributor
2007-08
Organization
NOAA Office for Coastal Management
NOAA/OCM
coastal.info@noaa.gov
2234 South Hobson Ave
Charleston
SC
29405-2413
(843) 740-1202
https://coast.noaa.gov
NOAA Office for Coastal Management Home Page
Online Resource
Metadata Contact
2007-08
Organization
NOAA Office for Coastal Management
NOAA/OCM
coastal.info@noaa.gov
2234 South Hobson Ave
Charleston
SC
29405-2413
(843) 740-1202
https://coast.noaa.gov
NOAA Office for Coastal Management Home Page
Online Resource
Point of Contact
2007-08
Organization
NOAA Office for Coastal Management
NOAA/OCM
coastal.info@noaa.gov
2234 South Hobson Ave
Charleston
SC
29405-2413
(843) 740-1202
https://coast.noaa.gov
NOAA Office for Coastal Management Home Page
Online Resource
Publication Date
-96.937465
-96.312465
28.738156
28.062456
Range
2006-06-26
2006-07-15
Yes
Unclassified
This data can be obtained on-line at the following URL: https://coast.noaa.gov/dataviewer;
None
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.
https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=97
Customized Download
Create custom data files by choosing data area, product type, map projection, file format, datum, etc.
https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/97/index.html
Bulk Download
Simple download of data files.
https://coast.noaa.gov
Online Resource
https://coast.noaa.gov/dataviewer
Online Resource
2016-05-23
Date that the source FGDC record was last modified.
2017-11-14
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.
2018-02-08
Partial upload of Positional Accuracy fields only.
2018-03-13
Partial upload to move data access links to Distribution Info.
Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.2.2.1350
FEMA LiDAR Specifications
FEMA LiDAR Specifications; +/- 18 cm in open terrain
None
None
1
Data Collection:
Using a LH Systems ALS50 Light Detection And Ranging (LiDAR) system, 64 flight lines of standard density (1.4 meter ground
sample distance) data were collected over areas in Calhoun County, TX (approximately 545 square miles). Multiple returns
were recorded for each laser pulse along with an intensity value for each return. The data acquisition occurred in 7 missions
between June 26, 2006 and June 28, 2006 and another collection between July 12, 2006 and July 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.
2007-08-01T00:00:00
2
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.
2007-08-01T00:00:00
3
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.
2007-08-01T00:00:00
4
Reflective Surface Generation:
The reflective surface is derived using the ALS Post Processor software by Leica Geosystems GIS & Mapping Division of Atlanta,
Georgia.
2007-08-01T00:00:00
5
LIDAR Point Classification
The classification and quality control (QC) of LiDAR data is carried out using TerraScan software by Terrasolid Limited of
Helsinki, Finland.
2007-08-01T00:00:00
6
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.
2007-08-01T00:00:00
7
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:
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.
2008-08-13T00:00:00
gov.noaa.nmfs.inport:50035
Anne Ball
2017-11-15T15:23:53
SysAdmin InPortAdmin
2022-08-09T17:11:37
2022-03-16
OCM Partners
OCMP
1002
Public
No
2022-03-16
1 Year
2023-03-16