GISDATA.trail_appalachian_25k

Frequently-asked questions:


What does this data set describe?

Title:
GISDATA.trail_appalachian_25k

Abstract:
This data set represents the most current depiction of the Appalachian National Scenic Trail centerline. Locational information used to create this data set were obtained from both Global Positioning Systems (GPS) survey data collected between 1998-2001 and information digitized from USGS topographical maps and Appalachian Trail maps.

Supplemental information:
The Appalachian National Scenic Trail is a footpath of approximately 2,169 miles in length that traverses the Appalachian Mountains from Maine to Georgia. It passes through 14 states and approximately 241 jurisdictions, and links some 75 national and state parks and forests.  Virtually every mile is within easy access of a major population center and some portion of the trail is within a day's drive of 2/3rds of the U.S. population. 



The idea for an Appalachian Trail was conceived by forester Benton MacKaye in 1921. In 1925, the Appalachian Trail Conference, a private not-for-profit organization, was founded specifically to coordinate the development of the Appalachian Trail. Its mission today is to preserve, manage, and promote the Appalachian Trail. By 1937, an Appalachian Trail footpath was considered complete and open for all to enjoy. In 1968, Congress passed the National Scenic Trails Act that created a system of national scenic trails, starting with the Appalachian Trail and Pacific Crest Trail. 

 

Though considered part of the national park system, the Appalachian Trail has largely remained managed by the Appalachian Trail Conference. This responsibility was formally delegated by the Department of the Interior in 1984. Today, the trail and its associated lands are managed by the Appalachian Trail Conference, its 31 affiliated trail clubs, and the National Park Service Appalachian Trail Park Office, in conjunction with several agency partners including the USDA Forest Service and numerous state park and state forest agencies.

  1. How should this data set be cited?

    Appalachian Trail Conference and National Park Service Appalachian Trail Park Office, 20011015, GISDATA.trail_appalachian_25k: Appalachian Trail Conference, Harpers Ferry, WV.

    Online links:

  2. What geographic area does the data set cover?

    Bounding coordinates:
    West: -84.199830
    East: -68.921782
    North: 45.904373
    South: 34.626563

  3. What does it look like?

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

    Calendar date: REQUIRED: The year (and optionally month, or month and day) for which the data set corresponds to the ground.
    Beginning date: 19981206
    Ending date: 20020312
    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?

      This is a Vector data set. It contains the following vector data types (SDTS terminology):
      • String (4560)
      • Point (4)

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

      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000000. Longitudes are given to the nearest 0.000000. 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 6378206.400000.
      The flattening of the ellipsoid used is 1/294.978698.

      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?

    GISDATA.trail_appalachian_25k
    OBJECTID
    Internal feature number.
    (Source:
    ESRI
    )

    Sequential unique whole numbers that are automatically generated.

    FNODE_
    Feature geometry.
    (Source:
    ESRI
    )

    Coordinates defining the features.

    TNODE_
    Internal node number for the beginning of an arc (from-node).
    (Source:
    ESRI
    )

    Whole numbers that are automatically generated.

    LPOLY_
    Internal node number for the end of an arc (to-node).
    (Source:
    ESRI
    )

    Whole numbers that are automatically generated.

    RPOLY_
    Internal node number for the left polygon.
    (Source:
    ESRI
    )

    Whole numbers that are automatically generated.

    LENGTH
    Internal node number for the right polygon.
    (Source:
    ESRI
    )

    Whole numbers that are automatically generated.

    AT_
    Length of feature in internal units.
    (Source:
    ESRI
    )

    Positive real numbers that are automatically generated.

    AT_ID
    Internal feature number.
    (Source:
    ESRI
    )

    Sequential unique whole numbers that are automatically generated.

    ID
    User-defined feature number.
    (Source:
    ESRI
    )

    LENGTH_M
    Trail Maintaining Club responsible for a specific section of trail

    LENGTH_MI
    NOTES
    SOURCE
    SUPPLIER
    TRAIL_CLUB
    SHAPE
    Feature geometry.
    (Source:
    ESRI
    )

    Coordinates defining the features.

    SHAPE.LEN
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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?

    Appalachian Trail Conferene and National Park Service Appalachian Trail Park Office

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

    Matthew C. Robinson
    Appalachian Trail Conference
    GIS Specialist
    P.O. Box 807
    Harpers Ferry, West Virginia 25425
    USA

    (304) 535-6331 (voice)
    (304) 535-2667 (FAX)
    mrobinson@atconf.org
    Hours of Service: 9-5 EST
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Why was the data set created?

This data set was developed to provide a depiction of the Appalachian National Scenic Trail in an usable and easily transferable format between parties so that it can correctly be represented on digital and printed maps; to assist staff members, agency partners, and trail-maintaining clubs with trail and land management duties; and to help local planning agencies, telecommunications companies, and other groups with planning activities, such as siting new developments that could have a substantial impact on the scenic quality of the Appalachian Trail.

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How was the data set created?

  1. Where did the data come from?

    ATC and NPS ATPO (source 1 of 1)

    Appalachian Trail Conference and National Park Service Appalachian Trail Park Office, 20011015, Appalachian National Scenic Trail Centerline: Appalachian Trail Conference, Harpers Ferry, WV.

    Online links:
    Type of source media: CD-ROM
    Source scale denominator: 1:5,000 to 1:24,000
    Source contribution:
    Information used in compiling this data set was collected and contributed by Dr. Vernon Vernier (1998-1999), the Green Mountain National Forest (1999), the White Mountain National Forest (1999-2001), and A.T. staff members (1998-2001).

  2. What changes have been made?

    Date: 19981206-20020312 (change 1 of 4)
    The Appalachian National Scenic Trail Centerline data was created  from a number of sources. These include Global Positioning System (GPS) survey data collected by Dr. Vernon Vernier (1998-1999), the Green Mountain National Forest (1999), the White Mountain National Forest (1999-2001), and A.T. staff members (1998-2001) as well as some digitized information based on information depicted on USGS topographical maps and Appalachian Trail maps.
    
    
    
    
    All GPS data was post-process differentially corrected either by A.T. staff members or by the party that collected the data. Next, it was populated with data source and supplier information. All GPS data used to create this data set was collected using Trimble's recommended data capture settings (e.g. maximum PDOP of 6.0 and elevation mask of 15 degrees) except the Manual 3D setting for those data collected by Dr. Vernier. Dr. Vernier used the Automatic data setting, which collects 3D GPS data when available and 2D GPS data all other times. Those portions of the data based on 3D GPS data and those based on 2D GPS data were identified and noted in the data. All GPS data were then combine to produce a seamlessly data set and attribute information (e.g. length) was updated for the entire set.
    
    
    
    
    Gaps were then identified and supplemented using digital data based on information depicted on USGS 1:24,000 scale topographic maps and Appalachian Trail maps, which vary in scale from 1:24,000 to 1:100,000. Attribute information (e.g. length) was then updated for the entire set.
    
    
    
    Data were then compared to a list of major trail relocations since 1998. Those portions of the data set that no longer accurately depicted the current trail location (e.g. the trail had been relocated since the GPS data in that area was collected) were replaced with digitized information, based on the most accurate and up-to-date information available as to the current trail location, whether that be an Appalachian Trail map (1:24,000 to 1:100,000 scale) or marked up USGS topographic maps (1:24,000 scale). Once combine with the rest of the data set, attribute information (e.g. length and data source) were updated for the entire set.
    
    
    
    
    As more accurate and up-to-date information is collected or becomes available, it will be incorporated within, or used to update, the current data set.

    (change 2 of 4)
    Metadata imported.

    Data sources used in this process:
    • C:\WorkSpace\AT_Centerline\at_centerline.xml

    (change 3 of 4)
    Dataset copied.

    (change 4 of 4)
    Dataset copied.

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

  1. How well have the observations been checked?

    All attributes associated with this data set were verified and should reflect the qualities of each portion of the data. Length (distance) information was calculated within the GIS though, so may not accurately reflect true distance values such as those calculated on the ground with a wheel or other measuring device. These values may also vary slightly throughout the data set, depending on the source data used to determine length.

  2. How accurate are the geographic locations?

    Horizontal accuracy of this data set varies depending on the source data from which it was compiled. All GPS data used to create this data set were collected using Trimble GeoExplorer II, ProXL, or ProXR GPS equipment and  post-process differentially corrected. However, in some areas this included only 2D GPS data (which is generally less accurate than 3D GPS data). Though no formal tests were conducted, all portions of the data based on 3D data are assumed to meet National Mapping Standards of +/- 46.5 feet horizontal accuracy at a 95% confidence level. Portions based on 2D data, however, may exceed National Mapping Standards in some areas. All portions of the data based on GPS data are noted within the attribute information.
    
    
    
    
    
    All digitized information used to create this data set were based on information depicted on USGS 1:24,000 topographic maps or Appalachian Trail maps, which vary in scale from 1:24,000 to 1:100,000. Generally, this information was only used as a supplement to the GPS data (e.g. in areas where no GPS data was collected or where GPS data did not reflect current conditions such as recent relocations). Though no formal tests were conducted, those portions of the data based on USGS topographic map information are assumed to be within National Mapping Standards. Those based on Appalachian Trail map information, however, may exceed National Mapping Standards in some areas. All portions of the data based on digitized information are noted within the attribute information.

  3. How accurate are the heights or depths?

    Not applicable.

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

    All portions of the Appalachian National Scenic Trail are represented within this data set using the most accurate information available. This includes high accuracy Global Positioning Systems (GPS) data in some areas and digitized information from USGS topographic maps and Appalachian Trail maps in others. As more accurate and up-to-date information is collected or becomes available, it will be incorporated within, or used to update, the current data set.

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

    Information within this data set are considered to be logically consistent, though no formal tests were performed. Line geometry is topologically clean.

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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: It is asked that proper citation be used on any materials (digital or printed) in which this information appears.
Use constraints:
Although a large portion of this data is quite accurate, the information depicted in this data set is for general reference purposes only and does not represent legal survey information. The Appalachian Trail Conference, the National Park Service Appalachian Trail Park Office, agency partners (including other units of the National Park Service and the USDA Forest Service), and associated trail-maintaining clubs shall not be held responsible for use or misuse of this data. Please see the Distribution_Liability section for more detailed information.

Distributor 1 of 1

  1. Who distributes the data set?

    Matthew C. Robinson
    Appalachian Trail Conference
    GIS Specialist
    P.O. Box 807
    Harpers Ferry, West Virginia 25425
    USA

    (304) 535-6331 (voice)
    (304) 535-2667 (FAX)
    mrobinson@atconf.org
    Hours of Service: 9-5 EST

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

    This data set was developed to support the A.T. project and the mission and goals of the Appalachian Trail Conference and the National Park Service Appalachian Trail Park Office.

  3. What legal disclaimers am I supposed to read?

    Although a large portion of this data is quite accurate, the information depicted in this data set is for general reference purposes only and does not represent legal survey information. The Appalachian Trail Conference, the National Park Service Appalachian Trail Park Office, agency partners (including other units of the National Park Service and the USDA Forest Service), and associated trail-maintaining clubs shall not be held liable for improper or incorrect use of the data described and/or contained herein. These data are not legal documents and are not intended to be used as such. 
    
    
    
     
    
    
    
    The information contained in these data is dynamic and may change over time. The data are not better than the original sources from which they were derived. It is the responsibility of the data user to use the data appropriately and consistent with the limitations of geospatial data in general and these data in particular. The related graphics are intended to aid the data user in acquiring relevant data; it is not appropriate to use the related graphics as data. 
    
    
    
    
    
    
    
    The Appalachian Trail Conference and National Park Service give no warranty, expressed or implied, as to the accuracy, reliability, or completeness of these data. It is strongly recommended that these data be directly acquired from ATC or NPS and not indirectly through other sources that may have changed the data in some way. Although these data have been processed successfully on a computer system at both the Appalachian Trail Conference and the National Park Service, no warranty expressed or implied is made regarding the utility of the data on another system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. This disclaimer applies both to individual use of the data and aggregate use with other data.

  4. How can I download or order the data?

    • Availability in digital form:


    • Data format:
      Size: 6.830

    • Cost to order the data: None


    • Special instructions:

      Refer to http://www.appalachiantrail.org/ or the contact person listed within this metadata for ordering information or instructions.

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

    Refer to http://www.appalachiantrail.org/ or the contact person listed within this metadata for ordering information or instructions.

  6. What hardware or software do I need in order to use the data set?

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Who wrote the metadata?

Dates:
Last modified: 20040322
Last reviewed: 20020312

Metadata author:
Matthew C. Robinson
Appalachian Trail Conference
GIS Specialist
P.O. Box 807
Harpers Ferry, West Virginia 25425
USA

(304) 535-6331 (voice)
(304) 535-2667 (FAX)
mrobinson@atconf.org
Hours of Service: 9-5 EST

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

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

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