GIS Documents & Data Notes

 

  • GIS Data Information

    GENERAL NOTES ON GIS DATA:

    Planimetric data were prepared using photogrammetric methods from aerial photography dated April 24, 1999. These data comply with National Map Accuracy Standards (NMAS) and the American Society of Photogrammetry and Remote Sensing (ASPRS) Standards for 1” = 40’ scale mapping.
     
    Cadastral (parcel) data were compiled from recorded deeds, subdivision plans and other public records following a hierarchy of accuracy and source reliability. Coordinate geometry (COGO) methods were used to automate the real property data then registered to fit the planimetric layers. Users of these map data are hereby notified that the public primary information sources should be consulted for verification of the information contained in these map data.  The parcel layer was not used for property assessment purposes, nor should this data be use as a surrogate to field survey data.
     
    Primary utility features were collected using conventional and GPS surveying techniques and were located to a horizontal accuracy of +- one foot horizontal and +- 0.5 feet vertical.  All field procedures followed Federal Geodetic Control Subcommittee (FGCC) guidelines. Secondary utility features were captured by photogrammetric methods from aerial photography dated April 24, 1999, at a scale of 1” = 40’ or by digitizing 1” = 100’ scale utility record plans stored and maintained by the Town of Manchester Public Works and Water Departments.
     
    All Town of Manchester data has been projected to the Connecticut State Plane Coordinate System – FIPS Zone 0600-EPSG 2234, Horizontal Datum NAD-83, and Vertical Datum NAVD-88 with US Survey Feet as units.
     
    Data Accuracy is based on National Mapping Accuracy Standards (NMAS), i.e., 90% of well-defined visible features are within tolerance listed. It must be noted, however, that these accuracy tolerances are only suggested and are based on the conversion processes.  In no way does this GIS data replace field survey data. The Town of Manchester is not legally responsible for any features that fall outside these tolerances.

    If you have any questions, please contact the GIS Coordinator at richg@manchesterct.gov

     

 

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