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Metadata Identifier: gov.noaa.csc.maps:ct2011_usda_northwest_m2597

Aggregation Info | Bands | Citations | Constraints | Coverage Descriptions | Dimensions | Extents | Formats | Geographic Bounding Box
Georectified Information | Georeferenceable Information | Identifiers | Instruments | Mediums | OnlineResources | Operations
Platforms | Process Steps | Range Elements | Reference Systems | Responsible Parties | Series | Sources | Spatial Grids | Temporal Extents

MD_DataIdentification

Count Component Title Abstract
1 2011 U.S. Department of Agriculture- Natural Resources Conservation Service (USDA-NRCS) Topographic Lidar: Northwest Connecticut Earth Eye collected LiDAR data for approximately 1,703 square kilometers that partially cover the Connecticut counties of Litchfield and Fairfield. The nominal pulse spacing for this project was no greater than 1 point every 0.7 meters. Dewberry used proprietary procedures to classify the LAS according to project specifications: 1-Unclassified, 2-Ground, 7-Noise, 9-Water, 12-Overlap. Dewberry produced 3D breaklines and combined these with the final LiDAR data to produce seamless hydro flattened DEMs for the 1,742 tiles (1000 m x 1000 m) that cover the project area.
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SV_Identification

none found
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CI_Citation

Count Component Title Date Citation Identifier
1 2011 U.S. Department of Agriculture- Natural Resources Conservation Service (USDA-NRCS) Topographic Lidar: Northwest Connecticut
  • 2013-11-01
1 Lidar Final Report
    2 None
      1 North American Datum 1983
      • 2007-01-19
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      CI_Series

      none found
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      CI_ResponsibleParty

      Count Component Individual Organization Position Email Role Linkage
      1 resourceProvider http://www.epsg-registry.org/export.htm?gml=urn:ogc:def:crs:EPSG::4269
      1 Citation URL http://www.csc.noaa.gov/htdata/lidar1_z/geoid12a/data/2597/supplemental/ct2011_usda_northwest.pdf
      1 Barbara Alexander USDA/NRCS > Natural Resources Conservation Service, U.S. Department of Agriculture barb.alexander@ct.usda.gov pointOfContact
      1 Brian Mayfield Dewberry - Geospatial Services Group Project Manager bmayfield@dewberry.com processor
      1 NOAA CSC (originator) DOC/NOAA/NOS/CSC > Coastal Services Center, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce csc.info@noaa.gov originator
      1 NOAA CSC (publisher) DOC/NOAA/NOS/CSC > Coastal Services Center, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce csc.info@noaa.gov publisher
      1 NOAA CSC(distributor) DOC/NOAA/NOS/CSC > Coastal Services Center, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce csc.info@noaa.gov distributor
      1 NOAA CSC (processor) DOC/NOAA/NOS/CSC > Coastal Services Center, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce csc.info@noaa.gov processor
      1 Earth Eye processor
      1 EPSG Registry European Petroleum Survey Group publisher http://www.epsg-registry.org/
      1 Mike Sutherland(author) Mike Sutherland DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce mike.sutherland@noaa.gov author
      1 Mike Sutherland Mike Sutherland DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce mike.sutherland@noaa.gov distributor
      1 Mike Sutherland (processor) Mike Sutherland DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce mike.sutherland@noaa.gov processor
      1 U.S. Corp of Engineers (USACE) originator
      1 USDA/NRCS > Natural Resources Conservation Service, U.S. Department of Agriculture originator
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      CI_OnlineResource

      Count Component Linkage Name Description Function
      1 http://www.csc.noaa.gov/htdata/lidar1_z/geoid12a/data/2597/supplemental/ct2011_usda_northwest.pdf Lidar Final Report information
      1 http://www.epsg-registry.org/ European Petroleum Survey Group Geodetic Parameter Registry Registry that accesses the EPSG Geodetic Parameter Dataset, which is a structured dataset of Coordinate Reference Systems and Coordinate Transformations. search
      1 http://www.epsg-registry.org/export.htm?gml=urn:ogc:def:crs:EPSG::4269 NAD83 Link to Geographic Markup Language (GML) description of reference system. information
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      MD_Identifier or RS_Identifier

      Count Component Code
      1 Ellipsoid in Meters
      1 urn:ogc:def:crs:EPSG::4269
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      EX_Extent

      Bounding Box Temporal Extent
      Count Component Description West East North South Start End
      1 -73.513386 -72.996434 42.051671 41.588247 2011-12-13 2011-12-19
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      EX_GeographicBoundingBox

      Count Component West East North South
      1 -73.513386 -72.996434 42.051671 41.588247
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      EX_TemporalExtent

      Count Component Start End
      1 2011-12-13 2011-12-19
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      MD_Format

      Count Component Name Version specification
      1 LAZ
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      MD_Medium

      none found
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      MD_Constraints

      Count Component Use Limitation
      1 Lidar Use Limitation These data depict the elevations at the time of the survey and are only accurate for that time. 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. Any conclusions drawn from analysis of this information are not the responsibility of NOAA or any of its partners. These data are NOT to be used for navigational purposes.
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      MD_ReferenceSystem

      Count Component Code Authority Title
      1 Ellipsoid Ellipsoid in Meters
      1 NAD83 urn:ogc:def:crs:EPSG::4269 North American Datum 1983
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      MD_GridSpatialRepresentation

      none found
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      MD_Georeferenceable or MI_Georeferenceable

      none found
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      MD_Georectified or MI_Georectified

      none found
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      MD_Dimension

      none found
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      MD_CoverageDescription or MI_CoverageDescription

      none found
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      MD_Band or MI_Band

      none found
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      MI_RangeElementDescription

      none found
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      MD_AggregateInformation

      Count Component Title Code Association Type Code
      1 Lidar Final Report crossReference
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      LE_Source or LI_Source

      none found
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      LE_ProcessStep or LI_ProcessStep

      Count Component DateTime Description
      1 2011-12-01T00:00:00 Data for the U.S. Corp of Engineers High Resolution LiDAR Data Acquisition & Processing for Portions of Connecticut project was acquired by Earth Eye, LLC. The project area included approximately 657 contiguous square miles for portions of Connecticut including a buffer of 200 meters. LiDAR sensor data were collected with an Optech ALTM3100EA LIDAR System. No imagery was requested or delivered. The data was delivered in the UTM coordinate system, meters, zone 18, horizontal datum NAD83, vertical datum NGVD88, Geoid 09. Deliverables for the project included a raw (unclassified) calibrated LiDAR point cloud, survey control, and a final control report. The calibration process considered all errors inherent with the equipment including errors in GPS, IMU, and sensor specific parameters. Adjustments were made to achieve a flight line to flight line data match (relative calibration) and subsequently adjusted to control for absolute accuracy. Process steps to achieve this are as follows: Rigorous LiDAR calibration: all sources of error such as the sensor's ranging and torsion parameters, atmospheric variables, GPS conditions, and IMU offsets were analyzed and removed to the highest level possible. This method addresses all errors, both vertical and horizontal in nature. Ranging, atmospheric variables, and GPS conditions affect the vertical position of the surface, whereas IMU offsets and torsion parameters affect the data horizontally. The horizontal accuracy is proven through repeatability: when the position of features remains constant no matter what direction the plane was flying and no matter where the feature is positioned within the swath, relative horizontal accuracy is achieved. Absolute horizontal accuracy is achieved through the use of differential GPS with base lines shorter than 25 miles. The base station is set at a temporary monument that is 'tied-in' to the CORS network. The same position is used for every lift, ensuring that any errors in its position will affect all data equally and can therefore be removed equally. Vertical accuracy is achieved through the adjustment to ground control survey points within the finished product. Although the base station has absolute vertical accuracy, adjustments to sensor parameters introduces vertical error that must be normalized in the final (mean) adjustment. The minimum expected horizontal accuracy was tested during the boresight process to meet or exceed the National Standard for Spatial Data Accuracy (NSSDA) for a Horizontal accuracy of 1 meter RMSE or better and a Vertical Accuracy of RMSE(z) 9.25 cm.
      1 2012-01-01T00:00:00 Dewberry utilizes a variety of software suites for inventory management, classification, and data processing. All LiDAR related processes begin by importing the data into the GeoCue task management software. The swath data is tiled according to project specifications (1,000 m x 1,000 m). The tiled data is then opened in Terrascan where Dewberry uses proprietary ground classification routines to remove any non-ground points and generate an accurate ground surface. The ground routine consists of three main parameters (building size, iteration angle, and iteration distance); by adjusting these parameters and running several iterations of this routine an initial ground surface is developed. The building size parameter sets a roaming window size. Each tile is loaded with neighboring points from adjacent tiles and the routine classifies the data section by section based on this roaming window size. The second most important parameter is the maximum terrain angle, which sets the highest allowed terrain angle within the model. Once the ground routine has been completed a manual quality control routine is done using hillshades, cross-sections, and profiles within the Terrasolid software suite. After this QC step, a peer review and supervisor manual inspection is completed on a percentage of the classified tiles based on the project size and variability of the terrain. After the ground classification corrections were completed, the dataset was processed through a water classification routine that utilizes breaklines compiled by Dewberry to automatically classify hydrographic features. The water classification routine selects ground points within the breakline polygons and automatically classifies them as class 9, water. In addition to classes 1, 2, and 9, there is a Class 7, noise points. This class was only used if needed when points could manually be identified as low/high points. The fully classified dataset is then processed through Dewberry's comprehensive quality control program. The data was classified as follows: Class 1 = Unclassified. This class includes vegetation, buildings, noise etc. Class 2 = Ground Class 7= Noise Class 9 = Water The LAS header information was verified to contain the following: Class (Integer) GPS Week Time (0.0001 seconds) Easting (0.01 foot) Northing (0.01 foot) Elevation (0.01 foot) Echo Number (Integer 1 to 4) Echo (Integer 1 to 4) Intensity (8 bit integer) Flight Line (Integer) Scan Angle (Integer degree)
      1 2013-11-01T00:00:00 The NOAA Coastal Services Center (CSC) received topographic files in LAS V1.2 format. The files contained lidar elevation measurements, intensity values, scan angle values, return information, flightline information, and adjusted standard GPS time. The data were received in UTM Zone 18N, NAD83 coordinates and were vertically referenced to NAVD88 using the Geoid09 model. The vertical units of the data were meters. CSC performed the following processing for data storage and Digital Coast provisioning purposes: 1. The LAS header's total point count did not match the actual number of points contained in several files. The header counts were repaired using LASTools' Lasinfo. 2. The Global Encoding Bit of each LAS file was set to '1' to reflect the use of Adjusted Standard GPS Time. (NOTE: Tile 18TXM6117 does not contain GPS Time information) 3. The topographic las files were converted from orthometric (NAVD88) heights to ellipsoidal heights using Geoid09. 4. The topographic las files were converted from a Projected Coordinate System (UTM Zone 18N) to a Geographic Coordinate System (NAD83). 5. The topographic las files' horizontal units were converted from meters to decimal degrees. 6. The data were converted to LAZ format.
      1 2013-12-31T00:00:00 The NOAA National Geophysical Data Center (NGDC) received lidar data files via ftp transfer from the NOAA Coastal Services Center. The data are currently being served via NOAA CSC Digital Coast at http://www.csc.noaa.gov/digitalcoast/. The data can be used to re-populate the system. The data are archived in LAS or LAZ format. The LAS format is an industry standard for LiDAR data developed by the American Society of Photogrammetry and Remote Sensing (ASPRS); LAZ is a loseless compressed version of LAS developed by Martin Isenburg (http://www.laszip.org/). The data are exclusively in geographic coordinates (either NAD83 or ITRF94). The data are referenced vertically to the ellipsoid (either GRS80 or ITRF94), allowing for the ability to apply the most up to date geoid model when transforming to orthometric heights.
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      MI_Operation

      none found
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      MI_Platform

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      MI_Instrument

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