50036 tx2006_chambers_m90_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, flight lines of standard density (1.4 meter ground sample distance) data were collected over areas in Chambers County, TX (approximately 633 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 April 22, 2006, and June 12, 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 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. 10680 The Chambers 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: Chambers County, Texas" and may be viewed at: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/90/supplemental/ChambersCounty_factsheet.pdf Some of the issues noted in the fact sheet are the following: Tile Review: Formatting issues: a) no flightline source information, b) some noisy two-return data, and c) the majority of ground points were first of two (i.e., first of many) returns. These issues all appeared to be systematic, which, although does not necessarily affect accuracy, it raises flags about the overall data quality. Also the water in some areas (tiles) is classified as 'unclassified," which is acceptable, but doesn't conform to the American Society for Photogrammetry and Remote Sensing (ASPRS) standard for class 9 for water values. High elevation values also remain in the data set, although correctly classified as "unclassified." Bare Earth Point Density Review: There appears to be a strong "tile-specific" level of classification as evidenced by the bare-earth densities (see color variations in Figure 1 of the pdf). Water points have been removed to some degree in many tiles; however, in adjacent tiles no apparent effort was made to remove water points. In either case, bare-earth points in the water still largely remain. The larger issue is the lack of proper return number information, which raises flags about the accuracy of the data. Additional data issues include the coastal portions of the county where water was randomly classified and a tile-to-tile variation in classification "aggressiveness." There are also some missing data on the southwestern edge of the county and a low density strip (yellow) running through the middle-eastern portion of the county. A footprint of this data set may be viewed in Google Earth at: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/90/supplemental/2006_TWDB_Lidar_Chambers_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 -94.986985 -94.350885 29.906285 29.499985 Range 2006-04-22 2006-06-12 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=90 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/geoid18/90/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, flight lines of standard density (1.4 meter ground sample distance) data were collected over areas in Chambers County, TX (approximately 633 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 April 22, 2006, and June 12, 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. 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 field for more information about this review. 2008-08-13T00:00:00 gov.noaa.nmfs.inport:50036 Anne Ball 2017-11-15T15:23:54 SysAdmin InPortAdmin 2022-08-09T17:11:37 2022-03-16 OCM Partners OCMP 1002 Public No No 2022-03-16 1 Year 2023-03-16