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Phragmites 1968

Frequently-asked questions:


What does this data set describe?

Title:
Phragmites 1968

Abstract:
Phragmites 1968 is a 1:12,000-scale, polygon feature-based layer that includes areas where phragmites existed in 1968 along the lower Connecticut River corridor from the towns of Portland and Cromwell south to Long Island Sound.  This layer was published at the same time as the Phragmites 1994 layer in order to depict the historic differences in phragmites growth between 1968 and 1994.  The Phragmites 1968 layer was compiled using 1:12,000 black and white digital orthophotos obtained in 1968 as part of a Connecticut Department of Environmental Protection aerial mapping survey.  This data represents a particular point in time (1968).  It is not updated and does not depcit current conditions.  Features are polygon locations that represent the approximate location of phragmites growth in 1968.  Attribute information is comprised of the NAME68 attribute that identifies one of 25 general locations of phragmites growth.  Other attributes include AV_LEGEND that depicts the existence of phragmites, and ACREAGE that depicts the size of each polygon in acres.  Data was compiled at a 1:12,000 scale.

Supplemental information:
For additional information, refer to the complete report generated as a result of the study that commissioned the publication of the Phragmites 1968 and Phragmites 1994 layers.   This report is entitled "Spatial Pattern of Phragmites Australis (CAV) Trin ex Steuf. Within the Tidelands of the Connecticut River, 1994"  and was authored by Nels Barrett (United States Department of Agriculture Natural Resources Conservation Service, 344 Merrow Road, Suite A., Tolland, Connecticut 06084 USA) and Sandy Prisloe (University of Connecticut Cooperative Extension System, College of Agricultural and Natural Resources, P.O. Box 70, Haddam, CT 06438 USA).  

  1. How should this data set be cited?

    U.S. Department of Agriculture Natural Resources Conservation Service (data compiler and editor), University of Connecticut Cooperative Extension System (data compiler and editor), State of Connecticut, Department of Environmental Protection (data publisher), 1995, Phragmites 1968: State of Connecticut, Department of Environmental Protection, Hartford, Connecticut, USA.

    Online links:
    Other citation details:
    This layer includes information that is static and was compiled at a specific point in time. It is not updated.

  2. What geographic area does the data set cover?

    Bounding coordinates:
    West: -72.452450
    East: -72.299130
    North: 41.444400
    South: 41.265219

  3. What does it look like?

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/phragmites1968fullview.gif (GIF)
    Full view of Phragmites 1968

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/phragmites1968detailview.gif (GIF)
    Detail view of Phragmites 1968

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

    Calendar date: 1995
    Currentness reference:
    publication date

  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?

      Indirect spatial reference:
      State of Connecticut, United States of America

      This is a Vector data set. It contains the following vector data types (SDTS terminology):
      • G-polygon (909)

    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 coordinate pair.
      Abscissae (x-coordinates) are specified to the nearest 0.000250.
      Ordinates (y-coordinates) are specified to the nearest 0.000250.
      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 resolution: 1.000000
      Altitude encoding method: Explicit elevation coordinate included with horizontal coordinates

  7. How does the data set describe geographic features?

    Phragmites 1968
    Phragmites growth in 1968 represented as polygon features. (Source: State of Connecticut, Department of Environmental Protection)

    OBJECTID
    Internal feature number. (Source: ESRI)
                      

    Sequential unique whole numbers that are automatically generated.

    NAME68
    Name of location where phragmites exists. (Source: State of Connecticut, Department of Environmental Protection)
                      

    ValueDefinition
    Black Hall River
    Black Hall River area
    Calves Island
    Calves Island area
    Chapman Pond
    Chapman Pond area
    Chester Creek
    Chester Creek area
    Deep River
    Deep River area
    Duck River
    Duck River area
    Essex Middle Cove Complex
    Essex Middle Cove Complex area
    Fenwick
    Fenwick area
    Ferry Point
    Ferry Point area
    Goose Island
    Goose Island area
    Great Island
    Great Island area
    Great Meadow / Essex North Cove
    Great Meadow / Essex North Cove area
    Griswold Point
    Griswold Point area
    Hamburg Cove
    Hamburg Cove area
    Joshua Creek
    Joshua Creek area
    Lieutenant River North
    Lieutenant River North area
    Lieutenant River South
    Lieutenant River South area
    Lord Cove
    Lord Cove area
    North Cove
    North Cove area
    Nott Island
    Nott Island area
    Otter Cove
    Otter Cove area
    Post & Prat Cove
    Post & Prat Cove area
    Ragged Rock Creek
    Ragged Rock Creek area
    Smiths Neck
    Smiths Neck area
    South Cove
    South Cove area
    Upper Island Marsh Complex
    Upper Island Marsh Complex area

    ACREAGE
    Size of feature in acres (Source: State of Connecticut, Department of Environmental Protection)
                      

    Real numbers that are calculated.

    SHAPE
    Feature geometry. (Source: ESRI)
                      

    Coordinates defining the features.

    Shape
    Feature geometry. (Source: ESRI)
                      

    Coordinates defining the features.

    SHAPE.area
    SHAPE.len
    Entity and attribute overview:
    Includes Phragmites 1968 features such as the location and size of the polygon.  Attributes include AV_LEGEND, which identifies the polygon as phragmites, ACREAGE, which identifies the size of the polygon in acres, and NAME68, which identifies the general location (one of 25 areas) of the feature.  This layer is best symbolized as a single feature type.  
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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?

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

    Kevin O'Brien
    State of Connecticut, Department of Environmental Protection
    79 Elm Street
    Hartford, Connecticut 06106-5127
    USA

    860-424-3034 (voice)
    860-424-4054 (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?

Phragmites 1968 is 1:12,000 scale data that depicts the locations of phragmites growth in 1968.  Use this layer to show the extent of phragmites growth in 1968 along the lower Connecticut River corridor.  In addition, this layer can be used with Phragmites 1994 that depicts the locations of phragmites growth in 1994.  The use of both of these layers can more clearly demonstrate the extent of invasive growth of phragmites between 1968 and 1994.  Not intended for maps printed at map scales greater or more detailed than 1:12,000 scale (1 inch = 1,000 feet).

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How was the data set created?

  1. Where did the data come from?

    Source 1 - 1968 Orthophotos (source 1 of 5)

    State of Connecticut, Department of Environmental Protection, 1968, 1968 Digital Orthophotos: State of Connecticut, Department of Environmental Protection, .

    Other citation details:
    These maps were prepared for the Department of Environmental Protection as a mapping survey project.

    Type of source media: paper
    Source scale denominator: 12000
    Source contribution:
    The 1968 orthophotos were used as the base map for locating and identifying phragmites and ground control points with the use of a stereoscope.

    Source 2 - 12,000 Scale Mylar Overlays (source 2 of 5)

    State of Connecticut, Department of Environmental Protection, 1995, 12,000 Scale Mylar Overlays: State of Connecticut, Department of Environmental Protection, .

    Type of source media: mylar overlays
    Source scale denominator: 12000
    Source contribution:
    This source was created by manually interpreting phragmites areas onto mylar that was overlaid onto Source 1, the 1968 digital orthophotos.  

    Source 3 - TIF images of Orthophotos and Mylar Overlays (source 3 of 5)

    State of Connecticut, Department of Environmental Protection, 1995, TIF images of Orthophotos and Mylar Overlays: State of Connecticut, Department of Environmental Protection, .

    Type of source media: disc
    Source scale denominator: 12000
    Source contribution:
    After completion of the mylar overlays, the orthophotos and the mylars were scanned and saved at 300 dpi in tagged image file (tif) format.  

    Source 4 - Rectified Scanned Imagery (source 4 of 5)

    State of Connecticut, Department of Environmental Protection, 1995, Rectified Scanned Imagery: State of Connecticut, Department of Environmental Protection, .

    Type of source media: disc
    Source scale denominator: 12000
    Source contribution:
    This data source was created when the tif images in Source 3 were scanned and rectified using established ground control points referenced in Source 1.  

    Source 5 - Phragmites 1968 Shapefile (source 5 of 5)

    1995, Phragmites 1968 Shapefile: State of Connecticut, Department of Environmental Protection, .

    Online links:
    Type of source media: disc
    Source scale denominator: 12000
    Source contribution:
    This data source refers to all features combined in one statewide layer. Since initial publication in 1995, a subsequent edition of the layer was generated by the State of Connecticut in order to convert from NAD 27 to NAD 83.  Changes made to the entire layer are reflected in metadata process steps where this particular data source is cited as both the Source Used and the Source Produced.

  2. What changes have been made?

    Date: 1995 (change 1 of 5)
    Using a stereoscope and the 1:12,000 scale 1968 orthophotos, the phragmites invasive extent was manually interpreted by an ecologist, then transferred along with ground control points, e.g., large boulders, road/stream crossings, intersections, etc., to mylar overlays (Source 2).

    Person responsible for change:
    State of Connecticut, Department of Environmental Protection

    Data sources used in this process:
    • Source 1 - 1968 Orthophotos

    Data sources produced in this process:
    • Source 2 - 12,000 Scale Mylar Overlays

    Date: 1995 (change 2 of 5)
    The 1968 orthophotos (Source 1) and the mylar overlays (Source 2) were scanned at an optical resolution of 300 dpi and saved as gray-scale images in the tagged image file (tif) format (Source 3).  

    Person responsible for change:
    State of Connecticut, Department of Environmental Protection

    Data sources used in this process:
    • Source 1 - 1968 Orthophotos
    • Source 2 - 12,000 Scale Mylar Overlays

    Data sources produced in this process:
    • Source 3 - TIF images of Orthophotos and Mylar Overlays

    Date: 1995 (change 3 of 5)
    Using coordinates for the ground control points obtained from Digital Ortho Quarter Quads (DOQQs), the scanned imagery was rectified using Blue Marble Geographics Geographic Transformer software.  The registration of each aerial photograph and overlay used anywhere from five to fifty-three control points depending on the distribution of phragmites in the photograph, and was output to Connecticut State Plane Coordinates, NAD 27.  

    Person responsible for change:
    State of Connecticut, Department of Environmental Protection

    Data sources used in this process:
    • Source 3 - TIF images of Orthophotos and Mylar Overlays

    Data sources produced in this process:
    • Source 4 - Rectified Scanned Imagery

    Date: 1995 (change 4 of 5)
    Once the Rectified Scanned Imagery  (Source 4) was completed, the images were imported into ArcView 3 software where the boundaries were manually digitized (heads-up digitizing) to create the ArcView shapefile.  

    Person responsible for change:
    State of Connecticut, Department of Environmental Protection

    Data sources used in this process:
    • Source 4 - Rectified Scanned Imagery

    Data sources produced in this process:
    • Source 5 - Phragmites 1968 Shapefile

    Date: 1999 (change 5 of 5)
    Datum conversion - Using DEPGIS Connecticut NADCON Extension for ESRI ArcView 3 software, the Phragmites 1968 layer was converted from the Connecticut State Plane Coordinate System of 1927 (NAD27) to the Connecticut State Plane Coordinate System of 1983 (NAD83). The NADCON (North American Datum CONversion) data transformation was used.

    Person responsible for change:
    State of Connecticut, Department of Environmental Protection

    Data sources used in this process:
    • Source 5 - Phragmites 1968 Shapefile

    Data sources produced in this process:
    • Source 5 - Phragmites 1968 Shapefile

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

  1. How well have the observations been checked?

    The Phragmites 1968 layer retains the feature types and information identified by the State of Connecticut, Department of Environmental Protection and obtained from the 1968 digital orthophotos.  Accuracy level of attributes is not known.  The AV_LEGEND attribute contains the string "Phragmites" for every feature.  The NAME68 field identifies the particular location (25 total locations) of the feature.  The ACREAGE attribute is a calculated field that depicts the area in acres of each feature.

  2. How accurate are the geographic locations?

    Horizontal accuracy of this layer is consistent only with the source data (1:12,000 scale digital orthophotos) from which features were compiled.  Feature locations were determined by using a stereoscope with the 1:12,000 orthophotos and identifying ground control points, e.g., large boulders, road/stream crossings, intersections, etc., on the photos.  An overall horizontal accuracy level cannot be determined.  

  3. How accurate are the heights or depths?

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

    The completeness of the data reflects the feature content of the data sources, which include the digital orthophotos (Source 1).  The Phragmites 1968 layer is complete in the sense that it accurately reflects 1968 phragmites information available at the time the layer was created.  This data is not updated and represents a particular point in time (1968).  This data does not represent all of the phragmites in Connecticut.  

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

    Polygon features conform to the following topological rules. Polygons are single part. There are no duplicate polygons. Polygons do not self overlap. Polygons do not overlap other polygons.  No automated procedures or tests were performed to guarantee desired topology other than visual inspection.

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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. The data is in the public domain and may be redistributed.
Use constraints:
No restrictions or legal prerequisites for using the data. The data is suitable for use at appropriate scale, and is not intended for maps printed at scales greater or more detailed than 1:12,000 scale (1 inch = 1,000 feet). Although this data set  has been used by the State of Connecticut, Department of Environmental Protection, no warranty, expressed or implied, is made by the State of Connecticut, Department of Environmental Protection 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, Department of Environmental Protection in the use of these data or related materials. The user assumes the entire risk related to the use of these data. Once the data is distributed to the user, modifications made to the data by the user should be noted in the metadata. When printing this data on a map or using it in a software application, analysis, or report, please acknowledge the State of Connecticut, Department of Environmental Protection as the source for this information.

Distributor 1 of 1

  1. Who distributes the data set?

    State of Connecticut, Department of Enviromental Protection
    79 Elm Street
    Hartford, Connecticut 06106-5127
    USA

    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

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

    Phragmites 1968

  3. What legal disclaimers am I supposed to read?

  4. How can I download or order the data?

    • Availability in digital form:


    • Data format:
      in format Shapefile, Feature Class (version ArcGIS)
      Network links:http://www.ct.gov/deep

    • Cost to order the data: An online copy of the data may be accessed without charge.


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

    The data distributor does not provide custom GIS analysis or mapping services. Data is available in a standard format and may be converted to other formats, projections, coordinate systems, or selected for specific geographic regions by the party receiving 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: 20120119

Metadata author:
Jacqueline Mickiewicz
State of Connecticut, Department of Environmental Protection
79 Elm Street
Hartford, Connecticut 06106-5127
USA

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

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

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