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Connecticut 1980 Coastal Photography Point Index

Frequently-asked questions:


What does this data set describe?

Title:
Connecticut 1980 Coastal Photography Point Index

Abstract:
The Connecticut 1980 Coastal Photography Point Index is a point feature class that defines the approximate center of the geographic area covered by each Connecticut 1980 Coastal Photography image.  The 1980 Coastal Photography data for Connecticut is comprised of 777 non-georeferenced 1:12,000 scale 9" by 9" vertical color infrared aerial images and these data include a point feature for each image.  The extent of all the tiles comprise a project area described by:

* all land areas within one-thousand (1000) feet of Mean High Water (MHW) and within one-thousand (1000) feet of state-regulated tidal wetlands; 
* an area of at least two-thousand (2000) feet waterward of the immediate shoreline of Long Island Sound; 
* all offshore islands within the territorial borders of the State of Connecticut including Goose Island and Falkner Island (offshore of Branford); Calf Islands and Great Captain Island (offshore of Greenwich); Norwalk Islands (offshore of Norwalk); Thimble Islands (offshore of Branford); Sandy Point (offshore of Stonington); and all islands in the Connecticut part of Fishers Island Sound; and 
* the main stem of the Connecticut River up to the Massachusetts State line. 

The Connecticut 1980 Coastal Photography Point Index is organized in a non-regular grid pattern that reflects the orientation of the flight lines needed to accurately and efficiently photograph the project area.  The points represent the centroid of features from the Connecticut 1980 Coastal Photography Tile Index. The tiles have an approximate sidelap (overlap between tiles in adjacent flightlines) of 30% and an approximate endlap (overlap between adjacent tiles within a flightline) of 60% in order to achieve well defined stereo pairs.

Each point feature is identified by a unique PHOTO_NO value, which matches the filename of the corresponding digital photo image as well as the hardcopy prints and transparencies maintined by the State of Connecticut Department of Environmantal Protection.  In addition, each point feature also contains the unique flight line, film roll, photo exposure numbers, and date recorded on the original film transparency and hardcopy print as well as basic information on the flight including the year, photography type, tide control, vegetation state, scale, etc.

NOTE: Due to problems in conforming to several contractual flight specifications for all images (namely coverage area, low-tide coordination, solar orientation, cloud coverage, and flight metrics,) this project was reflown in the Summer of 1981.

Supplemental information:
The Connecticut 1980 Coastal Photography is neither orthorectified nor georeferenced to any real-world coordinate sytem.  

To maximize the quality of the images and their contents, photography was specified to conform to the following environmental conditions: 
* photos were only taken during times of no/minimal cloud cover when lighting and weather conditions optimized the color infrared film; 
* solar altitude was more than thirty (30) degrees; 
* the ground detail was not obscured by flooding; 
* the foliage (salt marsh vegetation in particular) was fully developed; 
* seasonal conditions (summer) favored maximum human use/recreation activities (e.g., boats & temporary docks/structures in water, etc.); 
* photo times were planned within one (1) hour window before or after a predicted low tide based on National Oceanic & Atmospheric Administration (NOAA) predicted tide tables. (In instances where this window caused conflicts with the general restricted hours, tide coordination times superceded that limitation); and 
* no photography was flown between the hours 1100 and 1300 Eastern Standard Time (EST) to minimize specular reflection.

NOTE: Due to problems in conforming to several contractual flight specifications for all images (namely coverage area, low-tide coordination, solar orientation, cloud coverage, and flight metrics,) this project was reflown in the Summer of 1981.

The photos exist as 1:12,000 vertical color infrared images.  Color infrared photography, often called false color photography because it renders the scene in other than the normal colors seen by the human eye, is widely used for interpretation of natural resources.  Atmospheric haze does not interfere with the acquisition of the image, therefore is well suited to aerial photography.  Because the film is high speed and subject to degrees of degradation in handling before exposure, the aerial photographs can vary in overall tone.  This variability can complicate the interpretation of color tones between photographs, but some general guidelines can be given to aid the inexperienced interpreter. 

* The red tone of color infrared aerial photographs is almost always associated with live vegetation. Very intense reds indicate vegetation which is growing vigorously and is quite dense.  Knowledge of the vigor and density of vegetation is important to the interpretation of the red colors on color infrared aerial photography. 

* As the vigor and density of vegetation decreases, the tones may change to light reds and pinks. If plant density becomes low enough the faint reds may be overcome by the tones of the soils on which the plants are growing. The ground areas in this case will appear in shades of white, blue, or green depending on the kind of soil and its moisture content. As plant vigor decreases, the vegetation will show as lighter shades of red and pink, various shades of greens, and possible tans.  Dead vegetation will often be shades of greens or tans. 

* Bare soils will appear as shades of white, blue, or green in most agricultural regions.  In general, the more moist the soil the darker the shade of that particular soil color. Composition of the soil will affect the color tones shown on the photographs.  Dry sand will appear white and, with more moisture, may be very light gray or possibly light tan.  Clayey soils will generally be darker in color than sands and tend toward tans and bluegreens.  Again, wetter clays will be darker shades of the same tones.  Soils high in organic matter, like silts and loams will be even darker in color, and usually in shades of blues and greens.  Wet organic soils can be very dark blue or green in the aerial photographs. 

* Man-made features will show in the tones that relate to the materials they are made of.  Asphalt roads, for example, will be dark blue or black, gravel or dirt roads will show as lighter colors, depending on the soil materials involved in their composition, and concrete roads will appear light in tone, assuming clean concrete.  The buildings and streets of towns can be considered in a similar manner, their color dependent on the material they are made of. 

* Water will appear as shades of blue, varying from nearly black to very pale blue.  Clear, clean water will appear nearly black.  As the amount of sediment increases, the color becomes increasingly lighter blue.  Very shallow water will often appear as the material present in the bottom of the stream.  For example, a very shallow stream with a sandy bottom will appear white due to the high level of reflection of the sand. 

* Degraded film will result in photographs which have an overall blue or green cast.  When that occurs, the interpretation must consider what that overall cast will do to a "normal" rendition of the scene. 

(Description and guidelines for color infrared photography taken from the United States Geological Survey Aerial Photo FAQ web page, http://edc.usgs.gov/guides/news/aerialfaq.htmlt#A10)

  1. How should this data set be cited?

    State of Connecticut, Department of Environmental Protection (compiler, editor, and publisher), 2007, Connecticut 1980 Coastal Photography Point Index: State of Connecticut, Department of Environmental Protection, Hartford, Connecticut, USA.

    Online links:
    Other citation details:
    Connecticut 1980 Coastal Photography Point Index references a set of digital color infrared imagery collected and compiled during the 1980 Connecticut Coastal Color Infrared Aerial Photography Project by Aero Graphics, Corp. for the State of Connecticut Department of Environmental Protection.

    This is part of the following larger work:

    Aero Graphics, Corp. (data compiler), The State of Connecticut Department of Environmental Protection is maintainer and producer (publisher) of this data for use., 1980, 1980 Connecticut Coastal Photography Project.

    Other citation details:
    Aero Graphics Corp. was contracted by the State of Connecticut to provide the Connecticut 1980 Coastal Photography. Contract deliverables included 9" by 9" hardcopy black & white photo prints, 9" by 9" original color infrared film transparencies for stereoscopic viewing, hardcopy photo indexes, & 35mm oblique photo slides. NOTE: Due to problems in conforming to several contractual flight specifications for all images (namely coverage area, low-tide coordination, solar orientation, cloud coverage, and flight metrics,) this project was reflown in the Summer of 1981.

  2. What geographic area does the data set cover?

    Bounding coordinates:
    West: -73.683600
    East: -71.822426
    North: 42.032258
    South: 40.976854

  3. What does it look like?

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/photoindex1980coastfullview.gif (GIF)
    Full view of 1980 Photo Index Coast

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/photoindex1980coastdetailview.gif (GIF)
    Detail view of 1980 Photo Index Coast

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

    Beginning date: 19800718
    Ending time: 19801001
    Currentness reference:
    date of photography

  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 (777)

    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?

    Connecticut 1980 Coastal Photography Point Index
    Connecticut 1980 Coastal Photography Tile Index 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.

    PHOTOYEAR
    Feature geometry. (Source: ESRI)
                      

    Coordinates defining the features.

    ID_NO
    PHOTO_NO
    ROLL_NO
    FLTLINE_NO
    PHOTODATE
    PHOTOTIME
    PHOTOSCALE
    PHOTOCOLOR
    PHOTOTYPE
    TIDECNTRL
    VEGETATION
    SHAPE
    Feature geometry. (Source: ESRI)
                      

    Coordinates defining the features.

    AVFTPERPIX
    COMPILER
    MAINTAINER
    FILENAME
    PhotoYear
    Text field indicating the year the photos were taken in. (Source: State of Connecticut, Department of Environmental Protection)
                      

    ID_no
    Numeric field providing a unique identifier for each tile.  Idenitical value to PHOTO_NO. (Source: State of Connecticut, Department of Environmental Protection)
                      

    Photo_no
    Text field providing a unique identifier for each tile.  Idenitical value to ID_NO. (Source: State of Connecticut, Department of Environmental Protection)
                      

    Range of values
    Minimum:1
    Maximum:777

    Roll_no
    Identifies which roll of film was used for the photo(s.) (Source: State of Connecticut, Department of Environmental Protection)
                      

    Range of values
    Minimum:1
    Maximum:7

    FltLine_no
    Identifies which flight line was associated with the photo(s.) (Source: State of Connecticut, Department of Environmental Protection)
                      

    Range of values
    Minimum:1
    Maximum:47

    PhotoDate
    Identifies the specific date a photo was taken. (Source: State of Connecticut, Department of Environmental Protection)
                      

    PhotoTime
    Identifies the time a photo was taken, iff applicable.  Time values were only recorded for the first and last photos in a flightline. (Source: State of Connecticut, Department of Environmental Protection)
                      

    PhotoScale
    Scale of the photos. (Source: State of Connecticut, Department of Environmental Protection)
                      

    PhotoColor
    Type of film used to capture the photos. (Source: State of Connecticut, Department of Environmental Protection)
                      

    ValueDefinition
    Color Infrared
    [not provided]
    Black/White
    [not provided]
    True Color
    [not provided]
    Other
    [not provided]

    PhotoType
    Identifies the type of photo by classifying the camera orientation. (Source: State of Connecticut, Department of Environmental Protection)
                      

    ValueDefinition
    Scanned Vertical Aerial Film
    scanned version of aerial photo - no georeferencing/orthorectification
    Digital Orthophoto
    orthorectified digital photo

    TideCntrl
    Indicates if tide control was used an in what manner. (Source: State of Connecticut, Department of Environmental Protection)
                      

    ValueDefinition
    No - outside of specifications
    The photos do not conform to project specifications for this attribute.
    Yes - 1 hr. +/- predicted NOAA low tide
    The photos conform to project specifications for this attribute

    Vegetation
    Identifies during what state deciduous vegatation was in when the photography (Source: State of Connecticut, Department of Environmental Protection)
                      

    ValueDefinition
    Leaf on
    taken during leaf on conditions
    Leaf off
    taken during leaf off conditions

    DPI
    DPI (Dots Per Inch) of the digital scans of the original film transparencies. (Source: State of Connecticut, Department of Environmental Protection)
                      

    AvFtPerPix
    Calculation relating the scale of the photography to the DPI of the scanned imagery to provide a ground measurement, in feet, for each pixel.  Defined by [photo scale/image DPI/12] (Source: State of Connecticut, Department of Environmental Protection)
                      

    Compiler
    Entity responsible for compiling the original data. (Source: State of Connecticut, Department of Environmental Protection)
                      

    Maintainer
    Entity responsible for maintaining the current data. (Source: State of Connecticut, Department of Environmental Protection)
                      

    FileName
    Image File Name (Source: State of Connecticut, Department of Environmental Protection)
                      

    Entity and attribute overview:
    Information encoded about the point features includes the name of the corresponding photo image (PHOTO_NO), the aerial flight data (FLTLINE_NO, ROLL_NO, PHOTODATE, PHOTOTIME, PHOTOSCALE,  etc.) AND  project data (PHOTO_YR, VEGETATION, TIDE_CNTRL, etc.)

    Entity and attribute detail citation:
    not applicable
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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 Graphics Corp. was contracted by the State of Connecticut to provide the Connecticut 1980 Coastal Photography.  All imagery and data products were defined under State of Connecticut contract award number 790-A-5-2634.

  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

    860-424-3030 (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?

These data serve as a point index to the set of 1980 Coastal Photography image tiles for Connecticut.

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How was the data set created?

  1. Where did the data come from?

    Source 1 - Photo_index_1980Coastal_tile (source 1 of 2)

    State of Connecticut, Department of Environmental Protection (data compiler, editor and publisher), 2007, Connecticut 1980 Coastal Photography Tile Index: State of Connecticut, Department of Environmental Protection, Hartford, Connecticut, USA.

    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    Approximate geographic extent of 1980 photos used to derive centroid information.

    Source 2 - Photo_index_1980Coastal_point (source 2 of 2)

    State of Connecticut, Department of Environmental Protection (data compiler, editor and publisher), 2007, Connecticut 1980 Coastal Photography Point Index: State of Connecticut, Department of Environmental Protection, Hartford, CT.

    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    centroids of 1980 photo tiles.

  2. What changes have been made?

    Date: 2007 (change 1 of 1)
    Source 1 - Photo_index_1980Coastal_tile was used as input for the ArcGIS Toolbox application Features to Point, which created Source 2 - Photo_index_1980Coastal_point. 

    Person responsible for change:
    Kevin O'Brien
    State of Connecticut, Department of Environmental Protection
    79 Elm Street
    Hartford, Connecticut 06106
    USA

    860-424-3034 (voice)

    Data sources used in this process:
    • Source 1 - Photo_index_1980Coastal_tile

    Data sources produced in this process:
    • Source 2 - Photo_index_1980Coastal_point

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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 Connecticut 1980 Coastal Photography Point Index layer retains the feature types and attribute information identified by the State of Connecticut, Department of Environmental Protection (obtained from the flight specifcations) and contained in the source data for this layer, namely the Connecticut 1980 Coastal Photography Tile Index.  All attributes have valid values. Values are within defined domains.  No accuracy checks other than visual inspection of the fields were performed.

  2. How accurate are the geographic locations?

    The horizontal positional accuracy of this data is unknown.

  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 content of the data source, which is the State of Connecticut Department of Environmental Protection 1980 Coastal Photography and the Connecticut 1980 Coastal Photography Tile Index.  It is complete in the sense that it accurately reflects the number, extent, and location of the photos available at the time the State of Connecticut, Department of Environmental Protection created the layer. This data is not updated.

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

    Point features conform to the following topological rules. Points are single part. There are no duplicate points. Points do not overlap. Establishment of logical consistency was performed by the State of Connecticut, Department of Environmental Protection using ESRI ArcGIS software to manually create and control feature topology in shapefile format. No automated procedures or tests were performed to guarantee desired topology other than visual inspection.
    
    Establishment of logical consistency was performed by the State of Connecticut, Department of Environmental Protection using ESRI ArcGIS software to manually create and control feature topology in GEODATABASE format. 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. 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 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

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

    Connecticut 1980 Coastal Photography Point Index

  3. What legal disclaimers am I supposed to read?

    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.

  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:
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

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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