Bedrock Geologic Map of the Windham Quadrangle, Rockingham and Hillsborough Counties, New Hampshire: Polygon coverage for bedrock geologic units.

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Frequently anticipated questions:

What does this data set describe?

Title:
Bedrock Geologic Map of the Windham Quadrangle, Rockingham and Hillsborough Counties, New Hampshire: Polygon coverage for bedrock geologic units.
Abstract:
Polygon coverage for bedrock geologic units.
The geologic data was mapped during the summer of 1998 at a scale of 1:24,000. The bedrock geology was mapped using standard techniques. Locational information was provided by Rockwell PLGR+96 GPS receivers using the federal precise positioning service.
The line and polygon data were compiled on a mylar greenline of the 7.5-minute quadrangle 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 7.0.4. 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 (dbf) files into Arc/Info. The Arc/Info coverages were registered and transformed to the New Hampshire State Plane Coordinate system.
Supplemental_Information:
The geology dataset was printed and visually reviewed by the map authors and other USGS staff for geologic integrity, completeness, and accuracy of linework. The report received a standard internal peer review as per USGS Open-File Reports.
  1. How might this data set be cited?
    Walsh, Gregory J., and Stewart F. Clark, Jr., 1999, Bedrock Geologic Map of the Windham Quadrangle, Rockingham and Hillsborough Counties, New Hampshire: Polygon coverage for bedrock geologic units.: U.S. Geological Survey Open-File Report 99-8, U.S. Geological Survey, Reston, Virginia.

    Online Links:

    Other_Citation_Details: scale 1:24,000
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -71.3786087
    East_Bounding_Coordinate: -71.24776459
    North_Bounding_Coordinate: 42.87654114
    South_Bounding_Coordinate: 42.74621201
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: map
  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):
      • Point (205)
      • String (344)
      • GT-polygon composed of chains (206)
    2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitude and longitude values are specified in Decimal Degrees. The horizontal datum used is North American Datum of 1927.
      The ellipsoid used is Clarke 1866.
      The semi-major axis of the ellipsoid used is 6,378,206.4.
      The flattening of the ellipsoid used is 1/294.98.
  7. How does the data set describe geographic features?
    CONTX.PAT
    polygon attribute table for bedrock geologic units (Source: authors)
    CODE
    geologic unit label designators (Source: authors)
    ValueDefinition
    Dg 
    Dmg 
    Dp 
    Md 
    Mdp 
    SOb 
    SObq 
    SObw 
    Sad 
    Sag 
    Sagd 
    Sagdg 
    LBLTXT
    cartographic item used for selective plotting of polygon labels (Source: authors)
    ValueDefinition
    nno label (left blank)
    TYPE
    general category of rock unit (Source: authors)
    ValueDefinition
    mmetamorphic
    pplutonic
    CONTX.AAT
    arc attribute table for geologic contacts (Source: authors)
    TYPE
    type of geologic contact (Source: authors)
    ValueDefinition
    concealedcontact is under water
    CONTX.LUT
    lookup table describing characteristics of geologic polygons in PAT file (Source: authors)
    CODE
    same as code in PAT file (Source: authors)
    AGE_SORT
    relative age of rock units, by rank (integer values, 1 is youngest, 12 oldest) (Source: authors)
    Range of values
    Minimum:1
    Maximum:12
    Units:nominal
    Resolution:1
    MAP_UNIT
    brief description of geologic map unit (character text) (Source: authors)
    FORMATION
    name of geologic formation or rock unit (character text) (Source: authors)
    AGE
    geologic age of map unit (Source: authors)
    ValueDefinition
    Mesozoic 
    Devonian 
    Silurian 
    Ordovician 
    Silurian 

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Gregory J. Walsh
    • Stewart F. Clark, Jr.
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?

Why was the data set created?

The map was published as part of a study of the fractured bedrock aquifers in the state of New Hampshire. The digital data are intended for use by all government, academic, commercial, or other agencies in need of digital geologic map information.
Not intended for use at scales larger than 1:24,000.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  3. What similar or related data should the user be aware of?
    Walsh, Gregory J., and Stewart F. Clark, Jr., 1999, Bedrock Geologic Map of the Windham Quadrangle, New Hampshire: U.S. Geological Survey Open-File Report 99-8, U.S. Geological Survey, Reston, Virginia.

    Online Links:

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?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
  5. How consistent are the relationships among the observations, including topology?
    Polygon and chain-node topology present.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints:
Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness or any information, apparatus, product or process disclosed in this report, or represents that its use would not infringe privately owned rights. The act of distribution shall not constitute any such warranty and no responsibility is assumed by the USGS in the use of this data, or related materials. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.
This geologic map is a guide to the bedrock geology at 1:24,000 scale, but it is not a substitute for site specific data.
  1. Who distributes the data set?[Distributor contact information not provided.]
  2. What's the catalog number I need to order this data set?
  3. What legal disclaimers am I supposed to read?
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 14-Jun-2016
Metadata author:
Peter N Schweitzer
USGS Midwest Area
Collection manager, USGS Geoscience Data Clearinghouse, http://geo-nsdi.er.usgs.gov/
Mail Stop 954
12201 Sunrise Valley Dr
Reston, VA
USA

703-648-6533 (voice)
703-648-6252 (FAX)
pschweitzer@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://geo-nsdi.er.usgs.gov/metadata/open-file/99-8/contx.faq.html>
Generated by mp version 2.9.48 on Tue Jul 03 20:07:26 2018