SIR2012_5290_ACAD_Potentialbarriers

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Frequently anticipated questions:

What does this data set describe?

Title: SIR2012_5290_ACAD_Potentialbarriers
Abstract:
This layer shows landforms that are potential barriers to the horizontal migration of salt marshes in and around Acadia National Park (ANP), Maine. Landforms that are potential barriers to the migration of salt marshes include roads and railroad grades in this study area. Any artificial landform that intersected land that could be inundated with a sea level rise of 60 cm (+/- the 26 cm 95-percent confidence interval used in this study) was considered a potential barrier to marsh migration. The study did not attempt to distinguish between roads that had water passage (culverts) and those that did not, because the specific elevation and size of the culvert would ultimately determine how much of a barrier any given landform would present.
Supplemental_Information:
Geodatabase product of a U.S. Geological Survey 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_Potentialbarriers: U.S. Geological Survey, Augusta, Maine.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -68.786498
    East_Bounding_Coordinate: -68.002430
    North_Bounding_Coordinate: 44.574048
    South_Bounding_Coordinate: 44.147056

  3. What does it look like?

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

    Calendar_Date: 2010
    Currentness_Reference:
    Data were developed based on LiDAR topographic data collected in the fall of 2010. Changes to landforms since that time are not represented.

  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 (41)

    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?

    ploylines
    Potential barriers to saltmarsh migration (Source: USGS)

    Shape_Length
    Length of features in internal units (Source: ESRI)

    Positive real numbers that are automatically generated

    ANP_Association
    Indicates the ownership of the adjacent saltmarsh (Source: USGS)

    ValueDefinition
    privatePrivately held
    ANPOwned or otherwise protected by Acadia National Park (such as by a conservation easement).
    PartnerProtected by a conservation partner of Acadia National Park
    StateProtected by the State of Maine (Holbrook Island Sanctuary).

    Shape
    Feature Geometry (Source: ESRI)

    Coordinates defining features

    Type
    Type of artificial landform mapped (Source: USGS)

    ValueDefinition
    roadBarrier landform is a road, driveway, lane, etc.
    railroad gradebarrier landform is a railroad grade

    OBJECTID
    Internal feature number (Source: ESRI)

    Sequential unique whole numbers that are automatically generated

    Entity_and_Attribute_Overview:
    The Potential Barriers to Salt Marsh Migration layer contains lines representing the physical location of manmade topographic features that may present an obstacle to the migration of a salt marsh when sea level rises 60 cm. Whether or not the feature presents an actual obstacle depends on the location and function of water passage routes such as bridges and/or culverts.
    The Attribute Table for this layer contains the following items: OBJECTID -- Internal feature number Shape -- Feature Geometry Type -- Type of artificial landform mapped (road or railroad grade) Shape_Length -- Length of features in internal units (meters) ANP_Association -- Indicates the ownership of the adjacent saltmarsh: "Partner" = A conservation partner of Acadua National Park (ANP) owns the land "Yes" = ANP owns the land "no" = privately held, no association with ANP
    Entity_and_Attribute_Detail_Citation: none

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. Funding provided by 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. Acknowledgment of the U.S. Geological Survey and the National Park Service would be appreciated in products derived from these data.

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

    Martha G. Nielsen
    U.S. Geological Survey, Maine Water Science Office
    196 Whitten Rd.
    Augusta, Maine 04330

    207-622-8201 x116 (voice)
    207-622-8204 (FAX)
    mnielsen@usgs.gov

Why was the data set created?

Landforms that are potential barriers to the horizontal migration of salt marshes in and around Acadia National Park are potentially important in the analysis of the future viability of saltmarshes. Roads and railroad grades both may act as potential barriers. The potential barriers to migration of salt marshes in and around ANP were developed using the inundation lines for salt marshes with 60 cm of sea level rise, and a shaded-relief image of the LiDAR data on which the inundation lines were based. Aerial photographs (Low Tide orthophotos 2008, and Bing maps) were also used to delineate and identify potential barriers. The polylines are simply a graphical representation of a barrier (a road or railroad grade) that could be in the path of the rising sea. The lengths are somewhat aribtrary, and are just meant to show in general where the landform could impede water movement.

How was the data set created?

  1. From what previous works were the data drawn?

    LiDAR data (source 1 of 2)
    U.S. Geological Survey, 12/1/2011, LiDAR Data for the Northeast.

    Other_Citation_Details:
    The LiDAR data have a grid cell size of 2 m. Individual data tiles are 751x751 grid cells (1.5 km x 1.5 km) in size.
    As of October 2012, the LiDAR data are still availably only from state GIS offices. Final publication for public download has not been announced.
    Type_of_Source_Media: External hard drive
    Source_Scale_Denominator: 2400
    Source_Contribution:
    The LiDAR data were used to identify location/shape of potential barriers to migration of salt marshes. A shaded-relief image of tiles that were merged together (using the ArcGIS "mosaic" tool) was used in this process.

    LT 2008 (source 2 of 2)
    of, Maine Office GIS, 2009, Low Tide orthophotos 2008..

    Online Links:

    Type_of_Source_Media: online
    Source_Scale_Denominator: 2400
    Source_Contribution:
    Low-tide orthophotos from 2008 were used to help identify the potential barriers to migration. They were also used to identify the type of barrier (road or railroad grade).

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

    Date: 2011 (process 1 of 3)
    Creation of tile mosaics of the LiDAR data for use as background images and datasets. The LiDAR data exist in small (1.5 km x 1.5 km) tiles. They were combined using the ArcGIS Mosaic tool into larger pieces at the same resolution (2 m cell size). These mosaics were used to create shaded relief images of the topography.

    Date: 2011 (process 2 of 3)
    Creation of shaded relief images from the LiDAR data. Large mosaicked tiles were processed to create shaded relief images of the topography. The ArcGIS hillshade tool was used to create these images with the same grid size (2 m) as the original input data.

    Date: 2012 (process 3 of 3)
    Once the shaded relief image of the LiDAR data was created, the inundation lines layer (insert formal title here) was plotted over the shaded relief image for each salt marsh in the salt marshes inventory polygon layer (insert formal title here). If the inundation lines showed that, absent any physical barrier, water would move inland on the other side of any roadway or other manmade topographic feature, a line was digitized representing that manmade topographic feature. This process was repeated for each salt marsh in the salt marshes inventory set of polygons. Each potential barrier line was given a "type" label, which was determined based on the aerial photos (2008 low tide photos) and the shaded relief of the LIDAR data.

  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?

    The potential barriers were idenditified based only on remotely-sensed data and no attempt was made to ground-truth the data. Information on the type of barrier (road or railroad grade) was gathered from aerial photos, and was checked for each entity. Information on whether the potential barrier has any association with Acadia National Park, its properties, or properties of its conservation partners was gathered from a) GIS datasets of the park boundaries, and b) conversations with Park staff and staff of conservation partners working with the park (primarily Maine Coast Heritage Trust). No warranty is made concerning these attributions.

  2. How accurate are the geographic locations?

    The locations are based on very-high resolution aerial photographs and topographic data. Locations of roadways and railroad grades is accurate to within +/- 5 meters.

  3. How accurate are the heights or depths?

    Elevations not determined.

  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?

    Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of these data, software, or related materials. 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 13:46:04 2013