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Connecticut Terrain Dataset, version 2

Frequently-asked questions:

What does this data set describe?

Title:
Connecticut Terrain Dataset, version 2

Abstract:
Connecticut Terrain Dataset, version 2 is a digital terrain model of the state of Connecticut in ESRI terrain dataset format. The primary elevation point data sources for the terrain are the Connecticut 2000 LiDAR Masspoints, the Connecticut Coastline 2006 LiDAR Masspoints (ground only), and the Connecticut River 2004 LiDAR Masspoints. The USGS Topographic Map Masspoints provide additional elevation data in areas of data gaps in the Connecticut 2000 LiDAR Masspoints. The terrain also makes use of two boundary feature classes to clip the terrain to the Connecticut state boundary at different scale thresholds. This dataset is labeled "version 2" because as new LiDAR data becomes available, new statewide terrain datasets will be created.

  1. How should this data set be cited?

    State of Connecticut, Department of Energy and Environmental Protection, Connecticut Terrain Dataset, version 2.

  2. What geographic area does the data set cover?

    Bounding coordinates:
    West: -73.674684
    East: -71.818714
    North: 42.031406
    South: 40.978819

  3. What does it look like?

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/ctterraindatasetv2elevationfullview.gif (GIF)
    Full view of Connecticut Terrain Dataset Version 2 - Elevation

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/ctterraindatasetv2contoursfullview.gif (GIF)
    Full view of Connecticut Terrain Dataset Version 2 - Contours

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/ctterraindatasetv2slopefullview.gif (GIF)
    Full view of Connecticut Terrain Dataset Version 2 - Slope

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/ctterraindatasetv2aspectfullview.gif (GIF)
    Full view of Connecticut Terrain Dataset Version 2 - Aspect

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/ctterraindatasetv2coastdetailview.gif (GIF)
    Detail view of Connecticut Terrain Dataset Version 2 along the coast where the source is 3-foot posting LiDAR data

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/ctterraindatasetv2lidardifferencedetailview.gif (GIF)
    Detail view of Connecticut Terrain Dataset Version 2 at the junction of the 3-foot and 20-foot posting LiDAR data

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/CT Terrain Dataset v2 Data Sources.jpg (JPG)
    Coverage of data sources in Connecticut Terrain Dataset Version 2

  4. Does the data set describe conditions during a particular time period?

  5. What is the general form of this data set?

    Geospatial data presentation form: vector digital data

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Vector data set. It contains the following vector data types (SDTS terminology):
      • Entity point (62152)
      • Composite object (1292776)
      • Composite object (185029)
      • Composite object (61849)
      • GT-polygon composed of chains (4)

    2. What coordinate system is used to represent geographic features?

      The map projection used is NAD 1983 StatePlane Connecticut FIPS 0600 Feet.

      Projection parameters:
      NAD 1983 StatePlane Connecticut FIPS 0600 Feet
      Standard parallel: 41.2
      Standard parallel: 41.86666666666667
      Longitude of central meridian: -72.75
      Latitude of projection origin: 40.83333333333334
      False easting: 999999.999996
      False northing: 499999.999998

      Planar coordinates are encoded using coordinate pair.
      Abscissae (x-coordinates) are specified to the nearest 0.0003280833333333334.
      Ordinates (y-coordinates) are specified to the nearest 0.0003280833333333334.
      Planar coordinates are specified in Foot_US.

      The horizontal datum used is D North American 1983.
      The ellipsoid used is GRS 1980.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257222101.

  7. How does the data set describe geographic features?

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Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)


  2. Who also contributed to the data set?

    Connecticut 2000 LiDAR Masspoints was a part of the 2004 Statewide Aerial Survey of Connecticut, provided by Aero-Metric, Inc. of Sheboygan, Wisconsin on a contract with the State of Connecticut. TerraPoint LLC of Woodlands, Texas, was subcontracted to create a Connecticut Statewide LiDAR dataset. Connecticut River 2004 LiDAR Masspoints was acquired, processed, and delivered by Spectrum Mapping LLC of Denver, CO for the US Army Corps of Engineers. Connecticut Coastline 2006 LiDAR Masspoints (ground only) was collected and processed by TerraPoint, Inc, project managed by Dewberry, Inc of Fairfax, VA, and reviewed by Roald Haested, Inc for FEMA.

  3. To whom should users address questions about the data?

    State of Connecticut, Department of Energy and Environmental Protection
    79 Elm Street
    Hartford, CT 06106
    US

    860-424-3540 (voice)
    860-424-4058 (FAX)
    dep.gisdata@ct.gov
    Hours of Service: Monday to Friday, 08:30 to 16:30 Eastern Standard Time
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Why was the data set created?

Connecticut Terrain Dataset, version 2 has a wide range of uses including visual display and querying of elevation, slope, aspect, and contours; generation of raster digital elevation models (DEMs) and contour lines; and use as an input for analysis tasks such as creating viewsheds, calculating surface area and volume, and interpolating z-values to other data layers.

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How was the data set created?

  1. Where did the data come from?

    Connecticut Coastline 2006 LiDAR Masspoints (ground only) (source 1 of 5)

    Connecticut Coastline 2006 LiDAR Masspoints (ground only).

    Type of source media: None
    Source contribution:
    The Connecticut Coastline 2006 LiDAR Masspoints are an elevation data source for the terrain dataset. The data is 3-foot posting covering the Connecticut coastline (minus the mouth of the Connecticut River) and has a vertical accuracy of 0.33 feet at a 95% confidence interval.

    Connecticut 2000 LiDAR Masspoints (source 2 of 5)

    Connecticut 2000 LiDAR Masspoints.

    Type of source media: None
    Source contribution:
    The Connecticut 2000 LiDAR Masspoints are an elevation data source for the terrain dataset. The data is 20-foot posting covering the state of Connecticut, and has a horizontal positional accuracy of approximately 3 feet on the ground. However, the data has known limitations, including data gaps.

    Connecticut River 2004 LiDAR Masspoints (source 3 of 5)

    Connecticut River 2004 LiDAR Masspoints.

    Type of source media: None
    Source contribution:
    The Connecticut River 2004 LiDAR Masspoints are an elevation data source for the terrain dataset. The data is 3-foot posting covering the towns along the Connecticut River.

    USGS Topographic Map Masspoints (source 4 of 5)

    USGS Topographic Map Masspoints.

    Type of source media: None
    Source contribution:
    These point data were used to fill in some of the gaps that are a known limitation of the Connecticut 2000 LiDAR Masspoints. This data were derived from contour lines appearing on USGS 1:24,000-scale Digital Raster Graphics (DRGs) by the Center for Land Use Education and Research (CLEAR). The data were further edited by CT DEP to remove points that occurred in areas of dense LiDAR coverage.

    Connecticut LiDAR Data Boundary (source 5 of 5)

    Connecticut LiDAR Data Boundary.

    Type of source media: None
    Source contribution:
    This boundary layer is used to clip the terrain. It is a combination of the project areas of the Connecticut 2000 LiDAR Masspoints, the Connecticut River 2004 LiDAR Masspoints, and the Connecticut Coastline 2006 LiDAR Masspoints (ground only).

  2. What changes have been made?

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How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

  2. How accurate are the geographic locations?

  3. How accurate are the heights or depths?

  4. Where are the gaps in the data? What is missing?

  5. How consistent are the relationships among the observations, including topology?

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How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access constraints: Restriction Code: other restrictions; Other Constraints: Access constraints: Restriction Code: other restrictions; Other Constraints: Access constraints: None

Distributor 0 of 0

  1. Who distributes the data set?

  2. What's the catalog number I need to order this data set?

  3. What legal disclaimers am I supposed to read?

  4. How can I download or order the data?

  5. Is there some other way to get the data?

  6. What hardware or software do I need in order to use the data set?

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Who wrote the metadata?

Dates:
Last modified: 20110628

Metadata author:
Courtney Larson
State of Connecticut, Department of Environmental Protection
79 Elm Street
Hartford, CT 06106-5127
US

860-424-3540 (voice)
860-424-4058 (FAX)
dep.gisdata@ct.gov
Hours of Service: Monday to Friday, 08:30 to 16:30 Eastern Standard Time

Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata(FGDC-STD-001-1998)

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