Alaska Coastal Elevation Profiles: The data are downloadable as location-specific distribution packages. Within each package are delimited tabular files that contain the profile elevation data. Each file represents measurements from a specific point in time, organized by year and month.
DGGS Staff, 2014, Alaska Coastal Profile Tool (ACPT): Digital Data Series DDS 7, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.Online Links:
This is a point data set.
Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.00000001. Longitudes are given to the nearest 0.0000001. Latitude and longitude values are specified in decimal degrees.
The horizontal datum used is World Geodetic System of 1984.
The ellipsoid used is WGS84.
The semi-major axis of the ellipsoid used is 6378137.
The flattening of the ellipsoid used is 1/298.257223563.
In most cases the location value will be the name of the nearest community, however, other geographic feature or regional names may also be used.
Static measurements of the shoreface have been collected by a number of stakeholders in Alaska since the 1960s. This database is designed to present both modern and historic measurements. Year values are represented by four-digit numbers.
Month values are represented by one or two-digit numbers.
Day values are represented by one or two-digit numbers.
Latitude units are decimal degrees. Many of the measurements in this data set were originally published or recorded using a different coordinate system. To provide consistency throughout the database, all positional values have been standardized to the WGS 84 coordinate system. Users can find the uncertainty associated with the relative point locations in the corresponding Horizontal_Uncertainty field, for absolute horizontal uncertainty see 'How accurate are the geographic locations?'
Longitude units are decimal degrees. Many of the measurements in this data set were originally published or recorded using a different coordinate system. To provide consistency throughout the database, all positional values have been standardized to the WGS 84 coordinate system. Users can find the uncertainty associated with the relative point locations in the corresponding Horizontal_Uncertainty field, for absolute horizontal uncertainty see 'How accurate are the geographic locations?'
This is either the measured elevation value or a converted value that has been calculated to be consistent with related records for use in interactive, online mapping applications. Many of the measurements in this data set were originally published or recorded using a different coordinate system. When possible, we have converted all points throughout the database to use a consistent vertical datum. The vertical coordinate system for each elevation_plot value is specified in the corresponding Vertical_Datum_Plot field. Users can find the uncertainty associated with the relative point elevations in the corresponding Vertical_Uncertainty field, for absolute vertical uncertainty see 'How accurate are the heights or depths?'
This value specifies the vertical datum (and Geoid model or tidal Epoch, if necessary) and the units used to generate the Elevation_Plot value. The general format is similar to: 'NAVD88(Geoid12A), m'. When possible, we have converted all points throughout the database to use a consistent vertical datum.
Each location may have data for multiple shoreface elevation profiles. Line numbers are assigned to each elevation profile to differentiate between profiles. When a new profile is incorporated into the database, line numbers are generated according to the next available number in the sequence. When existing elevation profiles are re-measured, the data is linked to the historical measurements with this identifier.
Point numbers are unique within a given profile and assigned according to the next available number in the sequence. The number increases with distance from the open ocean.
The general format is similar to: 'M. DeRaps, A. Gould, N. Kinsman'.
Possibilities include, but are not limited to: DGPS (Differential Global Positioning System), DEM (Digital Elevation Model), Lidar, 'Emery Rod' differential leveling (Emery 1961), or Total Station.
Particle diameter is presented in millimeters. See Grainsize_Method field for additional information about how the grainsize was determined. Note: A zero value indicates that a grainsize measurement is not available.
Possibilities include, but are not limited to: sieve, wet sieve, visual assessment, or 'photo' (measurement approximation based on image autocorrelation techniques, Buscombe and others, 2010). Note: Blank field values indicate that a grainsize measurement is not available or the method is unknown.
Vertical positional uncertainty is provided in meters.
Horizontal positional uncertainty is provided in meters.
The measured elevation is provided in meters.
This value specifies the original vertical datum (and Geoid model or tidal Epoch, if necessary) and the units used at time of data collection. The vertical coordinate system for each elevation value is specified in the corresponding Vertical_Datum_Raw field. The general format is similar to: 'NAVD88(Geoid12A), m'.
This field is optionally populated to provide additional pertinent information that is not readily accommodated by the standardized fields.
Funding to develop this data set was provided, in part, by the Alaska Ocean Observing System. This work was also funded, in part, with qualified outer continental shelf oil and gas revenues through the Coastal Impact Assistance Program, U.S. Fish and Wildlife Service, U.S. Department of the Interior. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the opinions or policies of the U.S. Government. Mention of trade names or commercial products does not constitute their endorsement by the U.S. Government.
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This data set was created as a means to organize and provide public access to spatial data sets within the state of Alaska's coastal zone.
Buscombe, D., Rubin, D.M., and Warrick, J.A., 2010, A universal approximation of grain size from images of noncohesive sediment: Journal of Geophysical Research 115, 17, American Geophysical Union, USA.
Emery, K.O., 1961, A simple method of measuring beach profiles: Limnology and Oceanography v. 6, p. 90-93, Association for the Sciences of Limnology and Oceanography, USA.
Data sources used in this process:
National Marine Fisheries Service, National Oceanic and Atmospheric Administration., 2014, Alaska Shore Station Database.Online Links:
- https://alaskafisheries.noaa.gov/habitat/shorestation/default.htm
DGGS staff have performed visual qualitative assessment to ensure consistency.
Horizontal point location accuracy is highly dependent on the method of data collection. For DGPS data, the horizontal accuracies are presented as the Root Mean Square (RMS) error of the post-processed positions (typically lower than 10cm). For DEM-derived profile elevation data, the horizontal positional accuracy is dependent upon the ground-spacing of the point data. For elevation profiles obtained with various types of differential leveling techniques, the geographic accuracy of the entire profile location (approximately 10 cm to 1 km) is much poorer than the relative horizontal accuracy of the individual elevation points along each profile. Every effort has been made to infer appropriate horizontal accuracies for these varying methodologies based on all available information associated with the original data set.
Vertical point location accuracy is highly dependent on the method of data collection. For DGPS data, the vertical accuracies are presented as the Root Mean Square (RMS) error of the post-processed positions (typically lower than 10 cm). For DEM-derived profile elevation data, the vertical positional accuracy is dependent upon the reported vertical accuracy of the underlying data source. For elevation profiles obtained with various types of differential leveling techniques, the vertical accuracy of the entire profile location (approximately 10 cm to 1 m) is much poorer than the relative horizontal accuracy of the individual elevation points along each profile. Every effort has been made to infer appropriate vertical accuracies for these varying methodologies based on all available information associated with the original data set
Gaps in profile data exist when DGPS points failed to post-process. This is generally due to receiver malfunction or a low number of observed satellites. These gaps are typically apparent as unsampled sections when viewing the profile elevation data.
not applicable
Are there legal restrictions on access or use of the data?
- Access_Constraints:
- This report, map, and/or dataset is available directly from the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (see contact information below).
- Use_Constraints:
- Any hard copies or published datasets utilizing these datasets shall clearly indicate their source. If the user has modified the data in any way, the user is obligated to describe the types of modifications the user has made. The user specifically agrees not to misrepresent these datasets, nor to imply that changes made by the user were approved by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys. The State of Alaska makes no express or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product.
(907)451-5020 (voice)
(907)451-5050 (FAX)
dggspubs@alaska.gov
DDS 7
The State of Alaska makes no expressed or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product.
DGGS publications are available as free online downloads or you may purchase paper hard-copies or digital files on CD/DVD or other digital storage media by mail, phone, fax, or email from the DGGS Fairbanks office. To purchase this or other printed reports and maps, contact DGGS by phone (907-451-5020), e-mail (dggspubs@alaska.gov), or fax (907-451-5050). Payment accepted: Cash, check, money order, VISA, or MasterCard. Turnaround time is 1-2 weeks unless special arrangements are made and an express fee is paid. Shipping charge will be the actual cost of postage and will be added to the total amount due. Contact us for the exact shipping amount.
| Data format: | ASCII tabular files |
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| Network links: |
<http://dx.doi.org/10.14509/27359> <http://maps.dggs.alaska.gov/acpt/> |
(907)451-5020 (voice)