Bedrock Geologic Map of the New Milford Quadrangle, Litchfield and Fairfield Counties, Connecticut

Frequently-anticipated questions:

What does this data set describe?

    Title:
    Bedrock Geologic Map of the New Milford Quadrangle, Litchfield and Fairfield Counties, Connecticut
    Abstract:
    The bedrock geology of the New Milford quadrangle, Litchfield and Fairfield Counties, Connecticut is described in this report. The database includes contacts of bedrock geologic units, faults, outcrops, structural geologic information, and photos.
    Supplemental_Information:
    Data were originally collected in UTM coordinates, zone 18, NAD 1927, and reprojected to geographic coordinates (Lat/Long), NAD 1983. The database is accompanied by two large format color maps, an explanatory pamphlet, and a readme.txt file.


    This report is available from the internet at <http://pubs.usgs.gov/of/2003/of03-487/> or a CD is also available from -
    U.S. Geological Survey Information Services
    Box 25286 Federal Center
    Denver, CO 80225
    1-888-ASK-USGS
    ask@usgs.gov

    Printed paper maps are available from - USGS Maps on Demand <http://rmmcweb.cr.usgs.gov/public/mod/>

    The database includes geologic map data in Arc/Info export-interchange file equivalents (files with *.e00 extensions). These coverages provide the scientific content of the mapped data. The coverages include -
    CONTX--Polygon coverage for the contacts of geologic map units
    FAULTS--Line coverage of geologic faults
    OUTCROP--Polygon coverage of outcrops
    STRUX--Point coverage of geologic structure data
    PHOTO--Point coverage of photographs
    Base Map Data -
    NMbase.tif--Black and white TIFF bitmap image
    NMbase.tfw--Worldfile for registering image base

    The data are also available as ArcView shapefiles (*.dbf, *.shp, *.shx) and related DBF tables.
     
     

  1. How should this data set be cited?

    2.  

     

    Walsh, Gregory J. , 2003, Bedrock Geologic Map of the New Milford Quadrangle, Litchfield and Fairfield Counties, Connecticut: U.S. Geological Survey Open-File Report 03-487, scale 1:24,000.
     Online Links:
  2. What geographic area does the data set cover?

    3.  

     

    West_Bounding_Coordinate: -73.5000
    East_Bounding_Coordinate: -73.3750
    North_Bounding_Coordinate: 41.6250
    South_Bounding_Coordinate: 41.5000
  3. What does it look like?

    4.  

     

    <http://pubs.usgs.gov/of/2003/of03-487/034871p.gif> (GIF) and <http://pubs.usgs.gov/of/2003/of03-487/034872p.gif>
    Reduced-size images showing the general layout of the two map sheets.
  4. Does the data set describe conditions during a particular time period?

    5.  

     

    Beginning_Date: 2000
    Ending_Date: 2003
    Currentness_Reference: publication date
  5. What is the general form of this data set?

    6.  

     

    Geospatial_Data_Presentation_Form: map
  6. How does the data set represent geographic features?

    7.  

     

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


      2.  This is a Vector data set. It contains the following vector data types (SDTS terminology):

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


      3.  Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest .0001. Longitudes are given to the nearest .0001. Latitude and longitude values are specified in Decimal Degrees.

      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 6,378,137.
      The flattening of the ellipsoid used is 1/298.257.
       
       

  7. How does the data set describe geographic features?

    8.  

     

    Entity_and_Attribute_Overview: <http://pubs.usgs.gov/of/2003/of03-487/readme.txt>
    Entity_and_Attribute_Detail_Citation: <http://pubs.usgs.gov/of/2003/of03-487/readme.txt>

Who produced the data set?

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

    2.  

     

  2. Who also contributed to the data set?

    3.  

     

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

    4.  

     

    U.S. Geological Survey
    c/o Gregory J. Walsh
    Geologist
    P.O. Box 628
    Montpelier, Vermont 05601
    USA

    802-828-4528 (voice)
    802-828-4465 (FAX)
    gwalsh@usgs.gov

Why was the data set created?

The map was published as part of a study of fractured bedrock aquifers. The digital data are intended for use by all government, academic, commercial, or other agencies in need of digital geologic map information.

How was the data set created?

  1. From what previous works were the data drawn?

    2.  

     

    Walsh 2003 (source 1 of 1)
    Walsh, Gregory J. , 2003, Bedrock geologic map of the New Milford quadrangle, Litchfield and Fairfield Counties, Connecticut: U.S. Geological Survey Open-File Report 03-487, scale 1:24,000.

     Online Links:

    Other_Citation_Details:
    Walsh, G.J., 2003, Bedrock geologic map of the New Milford quadrangle, Litchfield and Fairfield Counties, Connecticut: U.S. Geological Survey Open-File Report 03-487, scale 1:24,000.
    Type_of_Source_Media: mylar
    Source_Scale_Denominator: 24000
    Source_Contribution:
    The geology was mapped by Walsh in 2000 and 2001. The database represents original work by Walsh
  2. How were the data generated, processed, and modified?

    3.  

     

    Date: 2003 (process 1 of 1)
    Geology mapped by Walsh in 2000 and 2001 at a scale of 1:24,000. Locational information was provided by Rockwell PLGR+96 GPS receivers using the Federal precise positioning service. The line and polygon data were compiled on mylar and scanned at 400 dpi on an Anatech Eagle 4080T scanner. The raster files (TIF) were converted to vector files (DXF) using GTX OSR version 2.0 raster-to-vector conversion software. The vector files were imported to Arc/Info version 8.0.2. Point data were collected with GPS and hand-held 3COM Palm Pilot III PDA computers. Data from the PDAs were combined in Microsoft Access, and then imported as ASCII text files and DBASE IV (dbf) files into Arc/Info.


    Person who carried out this activity:

    Gregory J. Walsh
    U.S. Geological Survey
    Geologist
    P.O. Box 628
    Montpelier, Vermont 05601
    USA

    802-828-4528 (voice)
    802-828-4465 (FAX)
    gwalsh@usgs.gov

    Hours_of_Service: 0900 to 1700 eastern standard time
    Data sources used in this process: Data sources produced in this process:

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

  1. How well have the observations been checked?


    2.  All attributes digitized during the creation process were verified by displaying the lines and points in the database with respect to the USGS 7.5-minute topographic map, but no formal tests were performed.

  2. How accurate are the geographic locations?


    3.  The data were created on a USGS 7.5 minute topographic map at 1:24000 scale. Therefore, the horizontal accuracy is assumed to be within National Map Accuracy Standards, with a horizontal accuracy of 45.6 feet at the 95% confidence level. Locational information in the field was provided by Rockwell PLGR+96 GPS receivers using the Federal precise positioning service. GPS positions were adjusted to match the existing topographic base.  Raw GPS data are located in the STRUX point coverage.

  3. How accurate are the heights or depths?


    4.  The data were delineated on a USGS 7.5 minute topographic map at 1:24000 scale. Therefore, the vertical accuracy is assumed to be within National Map Accuracy Standards, with a vertical accuracy of 11.9 feet at the 95% confidence level.

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


    5.  The geologic contacts were delineated on a USGS 7.5-minute topographic map based on observations at the outcrops shown in the database. Not all outcrops within the area were identified or visited during mapping. The geologic contacts might change if additional outcrops are discovered or exposed as the natural land changes or as the result of development. The features in the database are not based on legal parcels or definitions.

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


    6.  These data are believed to be logically consistent, though no tests were performed. Line geometry is topologically clean.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
 
 
Access_Constraints: none
Use_Constraints:
Although all data released in this report have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related materials and (or) the functioning of the software. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
  1. Who distributes the data set? (Distributor 1 of 1)

    2.  

     

    U.S. Geological Survey - Information Services
    Box 25286 Federal Center
    Denver, Colorado 80225
    USA

    1-888-ASK-USGS (voice)
    ask@usgs.gov

    Hours_of_Service: 0900 to 1700 mountain standard time
  2. What's the catalog number I need to order this data set?


    3. USGS Open-File Report 03-487

  3. What legal disclaimers am I supposed to read?

    4.  

     

    These data were prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, or implied, or assume any legal liability or responsibility the accuracy, completeness, or usefulness of any information, product or process disclosed in this report, and represents its use would not infringe privately owned rights. The act distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of this data related materials. Reference therein to any specific commercial product, process, or related service by trade name, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring the United States Government or any agency thereof.
  4. How can I download or order the data?

    5.  

     

Who wrote the metadata?

Dates:
Last modified: 19-Feb-2003

Last Reviewed: 2003
Metadata author:
U.S. Geological Survey
c/o Gregory J. Walsh
Geologist
P.O. Box 628
Montpelier, VT 05663
USA

802-828-4528 (voice)
802-828-4465 (FAX)
gwalsh@usgs.gov

Hours_of_Service: 0900 to 1700 eastern standard time
Metadata standard:
FGDC CSDGM (FGDC-STD-001-1998)

 

 
 
 
 

Generated by mp version 2.7.3 on Thu Feb 20 11:44:12 2003