SIR2012-5290_ACAD_SurveyedBMs

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Frequently anticipated questions:

What does this data set describe?

Title: SIR2012-5290_ACAD_SurveyedBMs
Abstract:
The U.S. Geological Survey (USGS) Salt marsh project at Acadia National Park(ANP)involved surveying elevation reference marks (ERMs) and points on the marsh surface for 20 marshes in the study area. Vertical control was established using previously-published benchmarks and one base station that was not previously published. This feature class contains location, elevation, and names for the vertical control points (published benchmarks and project benchmarks) used to establish vertical control for the ERMs and marsh points. In some cases, the project benchmarks are the same point as a published benchmark, and in some cases the project benchmark (BMs) were established close to the published benchmark, usually because the published benchmark was in a location that was not conducive to the placement of a base-receiver (usually because of tree cover).
Supplemental_Information:
Geodatabase product of a USGS study funded by National Park Service Climate Change Response funding, NPS PMIS # 161531, "Inventory and Protection of Salt Marshes from Risks of Sea Level Rise at Acadia National Park, Maine", 2012.
The database layers are collectively termed "appendix 1" of the USGS SIR report. Database layers included in appendix 1 include: Surveyed benchmarks used in surveying exercise (SIR2012_5290_ACAD_SurveyedBMs); Surveyed marsh points used for quality control for LiDAR data (SIR2012_5290_ACAD_Surveyedmarshpoints); Surveyed elevation reference marks for each surveyed marsh (SIR2012_5290_ACAD_SurveyedERMs); Salt marshes inventoried for this study (SIR2012_5290_ACAD_Saltmarshpolys); Inundation lines for each marsh under 60 cm of sea level rise (SIR2012_5290_ACAD_Inundationlines); Potential barriers to migration of salt marshes (SIR2012_5290_ACAD_Potentialbarriers).
The inundation lines presented are in no way a prediction of whether marsh migration will actually occur, only indications of where land will be inundated and would therefore be available for migration under 60 cm. of sea level rise.
  1. How should this data set be cited?

    U.S. Geological Survey, Maine Water Science Center, Augusta, Maine, 2012, SIR2012-5290_ACAD_SurveyedBMs: U.S. Geological Survey, Augusta, Maine.

    Online Links:

    This is part of the following larger work.

    Nielsen, Martha G., and Dudley, Robert W., 2012, Estimates of Future Inundation of Salt Marshes in Response to Sea Level Rise in and Around Acadia National Park, Maine: U.S. Geological Survey Scientific Investigations Report SIR2012-5290, U.S. Geological Survey, Reston, Virginia.

    Online Links:

    Other_Citation_Details: XXX p.

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -68.751374
    East_Bounding_Coordinate: -68.112956
    North_Bounding_Coordinate: 44.486092
    South_Bounding_Coordinate: 44.287125

  3. What does it look like?

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

    Beginning_Date: 12-Jul-2010
    Ending_Date: 28-Jul-2010
    Currentness_Reference: Currentness refers to when the benchmarks were surveyed.

  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):

      • Point (7)

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

      The map projection used is NAD_1983_UTM_Zone_19N.

      Projection parameters:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -69.0
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000.0
      False_Northing: 0.0

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.0001
      Ordinates (y-coordinates) are specified to the nearest 0.0001
      Planar coordinates are specified in meters

      The horizontal datum used is D North American 1983.
      The ellipsoid used is GRS 1980.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257222101.

      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: North_American_Vertical_Datum_1988
      Altitude_Resolution: 1.0
      Altitude_Distance_Units: Meters
      Altitude_Encoding_Method: Attribute values

  7. How does the data set describe geographic features?

    Surveyed benchmarks
    Point features (Source: Esri)

    OBJECTID
    Internal feature number (Source: Esri)

    Sequential unique whole numbers that are automatically generated.

    SHAPE
    Feature geometry (Source: Esri)

    Coordinates defining the features

    Point_ID
    USGS field identification of benchmark point (Source: USGS)

    Unique alphanumeric identification number

    Point_Type
    USGS field identification of benchmark point type (Source: USGS)

    ValueDefinition
    Control 
    SurvControl indicates the benchmark was a point established by the USGS for use with computation of ERM coordinates and elevations.

    Northing_f
    Northing horizontal point coordinate in feet (Maine State Plane East 1801 Survey Feet coordinate system) (Source: Esri)

    Range of values
    Minimum:227194.8832
    Maximum:297770.810
    Units:feet

    DiffFrmPub
    Difference between attribute fields Surv_elev_ft and Pub_elev_f (in feet). Some values null if published elevation was not available. (Source: USGS computed)

    Range of values
    Minimum:0.0333
    Maximum:0.2609
    Units:feet

    Easting_ft
    Easting horizontal point coordinate in feet (Maine State Plane East 1801 Survey Feet coordinate system) (Source: Esri)

    Range of values
    Minimum:918615.5447
    Maximum:1085258.163
    Units:feet

    Pub_elev_f
    Elevation of benchmark as published in the National Geodetic Survey (NGS) Benchmark database in feet above NAVD88. Null values if the point was not a published benchmark. (Source: NGS)

    Range of values
    Minimum:36.34
    Maximum:330.07
    Units:Feet above NAVD88

    Elev_M
    Vertical point coordinate in meters above NAVD88 (Source: USGS computed)

    Range of values
    Minimum:10.370973
    Maximum:34.025
    Units:Meters above NAVD88

    Surv_elev_ft
    Vertical point coordinate in feet above NAVD88 (Source: USGS computed)

    Range of values
    Minimum:34.025
    Maximum:330.103
    Units:Feet above NAVD88

    NGS_Nam
    Benchmark name as published in the National Geodetic Survey (NGS) Benchmark database. Null if not published in the NGS benchmark database. (Source: National Geodetic Survey (NGS) Benchmark database)

    Alphanumeric identification number. Missing = "-".

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?

    Produced in cooperation with the National Park Service. LiDAR data for the Northeast funded largely by USGS American Reinvestment and Recovery Act funds, and provided by the Maine Office of GIS (MEGIS). These data are in the public domain unless otherwise stated; please credit the USGS and the National Park Service in products derived from these data.

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

    Robert W. Dudley
    U.S. Geological Survey Maine Water Science Office
    Hydrologist
    196 Whitten Rd.
    Augusta, ME 04330

    207-622-8201 x115 (voice)
    207-622-8204 (FAX)
    rwdudley@usgs.gov

Why was the data set created?

Published benchmarks and other base stations used for differential Global Positioning System (GPS) surveying of ERMs and marsh points.

How was the data set created?

  1. From what previous works were the data drawn?

    Bing maps imagery (source 1 of 2)
    USGS, 2010, Microsoft Bing Bird's eye imagery: Microsoft Corporation, Redmond, Washington.

    Online Links:

    Other_Citation_Details:
    Copyright 2010 DigitalGlobe, Image courtesy of USGS Copyright 2012 Microsoft Corporation
    Type_of_Source_Media: Online digital image
    Source_Scale_Denominator: 1200
    Source_Contribution:
    The Bing map server was used to visually inspect and verify the surveyed locations of the benchmarks.

    NGS database (source 2 of 2)
    National Oceanic and Atmospheric Administration (NOAA), National Geodetic Survey, 2010, Horizontal and Vertical Geodetic Control Data for the United States: Unknown Unknown, NOAA's Ocean Service, National Geodetic Survey (NGS), NOAA Campus, Silver Spring, MD.

    Online Links:

    Other_Citation_Details:
    Questions concerning this data may be addressed to the NGS Information Center (ngs.infocenter@noaa.gov)
    Type_of_Source_Media: Online database
    Source_Contribution:
    Provided spatial and attribute information for permanent published benchmarks.

  2. How were the data generated, processed, and modified?

    Date: 2010 (process 1 of 2)
    The elevations of the BMs were determined using Leica high-precision (millimeter accuracy) dual-frequency GPS receivers. This technique used a GPS receiver (base) a survey monument having a known elevation; base-unit occupation times ranged from 5 hr to 10 hr 53 min, with an average occupation time of 7 hr 33 min. Base-receiver data were submitted to the NGS using OPUS (<http://www.ngs.noaa.gov/OPUS/about.jsp>). Base point elevations were solved by OPUS using the CORS network (<http://www.ngs.noaa.gov/CORS/>).

    Date: 2010 (process 2 of 2)
    X, Y, and Z coordinates from the survey data were put in a text file and imported into ArcGIS and saved as a shapefile.

  3. What similar or related data should the user be aware of?

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

  1. How well have the observations been checked?

    All attributes in the accompanying data layers were checked.

  2. How accurate are the geographic locations?

    Surveyed locations and elevations were solved using Online Positioning User Service (OPUS) precise processing service OPUS and the Continuously Operating Reference Stations (CORS) CORS network. Vertical and horizontal elevations: mean root mean square error (RMSE) = 16.1 millimeters (mm).

  3. How accurate are the heights or depths?

    Surveyed locations and elevations were solved using OPUS and the CORS network. Vertical and horizontal elevations: RMSE = 16.1 mm.

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

    The data are complete.

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

    Data are internally consistent.

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:
No legal use constraints. Users must assume responsibility in determining the usability of these data for their purposes.

  1. Who distributes the data set? (Distributor 1 of 1)

    U.S. Geological Survey
    Ask USGS -- Water Webserver Team
    445 National Center
    Reston, VA 20192
    USA

    1-888-275-8747 (1-888-ASK-USGS) (voice)
    <http://water.usgs.gov/user_feedback_form.html>

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

    Downloadable Data

  3. What legal disclaimers am I supposed to read?

    This database, identified as “SIR2012_5290_ACAD_SurveyedBMs”, has been approved for release and publication by the U.S. Geological Survey (USGS). Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the U.S. Government may be held liable for any damages resulting from its authorized or unauthorized use. The use of firm, trade, or brand names in this report is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey. The names mentioned in this document may be trademarks or registered trademarks of their respective trademark owners.

  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 20-Dec-2012
Metadata author:
U.S. Geological Survey, New England Water Science Center, Maine Office
Hydrologist
196 Whitten Rd.
Augusta, ME 04330
USA

207-622-8201 (voice)
mnielsen@usgs.gov

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

Generated by mp version 2.9.20 on Wed Mar 13 14:20:09 2013