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Connecticut Ground Elevation for 2000

Frequently-asked questions:


What does this data set describe?

Title:
Connecticut Ground Elevation for 2000

Abstract:
Connecticut Ground Elevation for 2000 is a digitial elevation model (DEM) dataset that represents 10-foot spatial resolution elevation information for the state of Connecticut. This elevation information for Connecticut was obtained from the University of Connecticut, College of Agriculture and Natural Resources, Center for Land Use Education and Research (CLEAR). It is derived from point elevation data available for Connecticut captured during the year 2000 using Light Detection And Ranging (LiDAR) technology. Note, the 2000 LiDAR data for Connecticut is not complete so this statewide elevation information may be incorrect in some areas. For unknown reasons, in some areas of the state there are gaps in the underlying LiDAR point data. This is a known limitation of the 2000 LiDAR data for Connecticut. In an effort to create a seamless statewide elevation dataset, the University of Connecticut, College of Agriculture and Natural Resources edited point elevation files to remove anomalous observations. Given the volume of data, there are likely errors present in the point data as well as in an interpolated surface. The elevation data are in a gridded format and are projected into the State Plane Coordinate System Zone 0600, orthometric heights (NAVD 88) in US Survey feet.

Supplemental information:
Based on a statewide 10 ft elevation grid in ArcInfo format named ct-lidar obtained from the University of Connecticut, College of Agriculture and Natural Resources. This information is derived from point elevation data available for Connecticut that was captured in 2000 using Light Detection And Ranging (LiDAR) technology.

  1. How should this data set be cited?

    University of Connecticut, College of Agriculture and Natural Resources (compiler, editor and publisher), State of Connecticut, Department of Environmental Protection (DEP), State of Connecticut, Department of Public Safety (DPS), State of Connecticut, Department of Transportation (DOT), Unknown, Connecticut Ground Elevation for 2000: University of Connecticut, College of Agriculture and Natural Resources , Storrs, Connecticut.

    Online links:
    Other citation details:
    Agencies that provided the funding to capture 2004 orthophotography and 2000 LiDAR elevation data for Connecticut include the DEP, DOT, and DPS.

  2. What geographic area does the data set cover?

    Bounding coordinates:
    West: -73.742925
    East: -71.780636
    North: 42.053163
    South: 40.972526

  3. What does it look like?

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/elevation2000fullview.jpg (JPEG)
    Full view of Connecticut Ground Elevation for 2000

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

    Calendar date: 2000
    Currentness reference:
    collection date

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

    Geospatial data presentation form: SDE raster digital data

  6. How does the data set represent geographic features?

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

      This is a Raster data set. It contains the following raster data types:
      • Dimensions 39224 x 53298 x 1, type Pixel

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

      The map projection used is Lambert Conformal Conic.

      Projection parameters:
      Lambert Conformal Conic
      Standard parallel: 41.200000
      Standard parallel: 41.866667
      Longitude of central meridian: -72.750000
      Latitude of projection origin: 40.833333
      False easting: 999999.999996
      False northing: 499999.999998

      Planar coordinates are encoded using row and column.
      Abscissae (x-coordinates) are specified to the nearest 10.000000.
      Ordinates (y-coordinates) are specified to the nearest 10.000000.
      Planar coordinates are specified in survey feet.

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

      Vertical coordinate system definition:
      Altitude system definition:
      Altitude datum name: North American Vertical Datum of 1988
      Altitude resolution: 1
      Altitude distance units: feet
      Altitude encoding method: Attribute values

  7. How does the data set describe geographic features?

    Connecticut Ground Elevation for 2000
    OBJECTID
    Internal feature number. (Source: ESRI)
                      

    Sequential unique whole numbers that are automatically generated.

    VALUE
    GRNDELEV_FT
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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?

    Aero-Metric, Inc. of Sheboygan Wisconsin was contracted by the State of Connecticut to provide the 2004 Statewide Aerial Survey of Connecticut. Contract deliverables include digital orthohotos, two sets of non-rectified prints for stereoscopic viewing, photo indexes, and LiDAR data. All 2004 Statewide Aerial Survey imagery and data products are defined under State of Connecticut contract award number RFP-990-A-14-0518-C (dated Feb 22, 2000), including contract award supplement #1 (dated Feb 28, 2002), contract award supplement #2 (dated Nov 4, 2004), contract award supplement #3 (dated Nov 26, 2004) and contract award supplement #4 (dated May 13, 2005). TerraPoint LLC of Woodlands Texas was subcontracted to create a Connecticut Statewide LIDAR dataset. 

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

    Center for Land Use Education & Research (CLEAR)
    University of Connecticut
    College of Agriculture and Natural Resources
    1066 Saybrook Road. PO Box 70
    Haddam, Connecticut 06438-0070
    USA

    860-345-4511 (voice)
    860-345-3357 (FAX)
    clear@uconn.edu
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Why was the data set created?

This information is used to represent ground elevation at a regional level and not intended for use at detailed scales or to determine the exact elevation at a particular location.

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How was the data set created?

  1. Where did the data come from?

    CT_LIDAR (source 1 of 1)

    University of Connecticut, College of Agriculture and Natural Resources (compiler, editor and publisher), State of Connecticut, Department of Environmental Protection (DEP), State of Connecticut, Department of Public Safety (DPS), State of Connecticut, Department of Transportation (DOT), Unknown, Connecticut LiDAR: University of Connecticut, College of Agriculture and Natural Resources, Storrs, Connecticut.

    Online links:
    Other citation details:
    Agencies that provided the funding to capture 2004 orthophotography and 2000 LiDAR elevation data for Connecticut include the DEP, DOT, and DPS.

    Type of source media: disc
    Source scale denominator: unknown
    Source contribution:
    The data source is an ArcInfo Grid named CT_LIDAR, which the University of Connecticut, College of Agriculture and Natural Resources derived from the Connecticut 2000 LiDAR dataset.

  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?

    The horizontal positional accuracy of this data is not known. The horizontal positional accuracy of the 20-foot posting LiDAR 2000 point data used to create this data product is approximately 3 feet on the ground. 

  3. How accurate are the heights or depths?

    The data are derived through the spatial interpolation of airborne LiDAR collected in the year 2000. There is a known limitation in the LiDAR data collected for Connecticut. The LiDAR data is not complete and did not cover all of Connecticut. For unknown reasons, elevation information was not captured in some areas, resulting in data gaps in the underlying LiDAR point data. These data gaps are a know limitation in the 20-foot posting LiDAR data collected for Connecticut during the year 2000. In an effort to create a seamless statewide elevation dataset, the University of Connecticut, College of Agriculture and Natural Resources edited point elevation files to remove anomalous observations. Given the volume of data, there are likely errors present in the point data as well as in an interpolated surface. 

  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: None. No restrictions or legal prerequisites for accessing the data. The data is in the public domain and may be redistributed.
Use constraints:
None. No restrictions or legal prerequisites for using the data after access is granted. The data are derived through the spatial interpolation of airborne LiDAR collected in the year 2000. There is a known limitation in the LiDAR data collected for Connecticut. The LiDAR data is not complete and did not cover all of Connecticut. For unknown reasons, elevation information was not captured in some areas, resulting in data gaps in the underlying LiDAR point data. These data gaps are a know limitation in the 20-foot posting LiDAR data collected for Connecticut during the year 2000. In an effort to create a seamless statewide elevation dataset, the University of Connecticut, College of Agriculture and Natural Resources edited point elevation files to remove anomalous observations. Given the volume of data, there are likely errors present in the point data as well as in an interpolated surface. 

Distributor 1 of 1

  1. Who distributes the data set?

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

    Connecticut Ground Elevation for 2000

  3. What legal disclaimers am I supposed to read?

    Although this data set  has been used by the State of Connecticut, no warranty, expressed or implied, is made by the State of Connecticut as to the accuracy of the data and or related materials.  The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the State of Connecticut in the use of these data or related materials. The user assumes the entire risk related to the use of these data.

  4. How can I download or order the data?

    • Availability in digital form:


    • Data format:
      in format GRID, Raster (version ArcGIS)
      Network links:http://www.ct.gov/deep

  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?

    Geographic information sytem (GIS), computer-aided drawing or other mapping software is necessary to display, view and access the information.

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Who wrote the metadata?

Dates:
Last modified: 20111208

Metadata author:
Howie Sternberg
State of Connecticut, Department of Environmental Protection
79 Elm Street
Hartford, Connecticut 06106
USA

860-424-3540 (voice)
dep.gisdata@ct.gov

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

Metadata extensions used:
  • http://www.esri.com/metadata/esriprof80.html

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