Overbeck, J.R., Hendricks, M.D., and Kinsman, N.E.M., 2017, Photogrammetric digital surface models and orthoimagery for the continuous coastline, Wales to Platinum, Alaska, segment B: Teller to Nome: Raw Data File RDF 2017-8B, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.
This is a raster data set.
Planar coordinates are encoded using coordinate pair
Abscissae (x-coordinates) are specified to the nearest .00000001
Ordinates (y-coordinates) are specified to the nearest .00000001
Planar coordinates are specified in Meters
The horizontal datum used is North American Datum of 1983.
The ellipsoid used is GRS 80.
The semi-major axis of the ellipsoid used is 6378137.
The flattening of the ellipsoid used is 1/298.257222101000025.
This publication is funded with qualified outer continental shelf oil and gas revenues by 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.
The State of Alaska Division of Geological & Geophysical Surveys contracted the acquisition of photogrammetric digital surface models (DSMs) and co-registered orthorectified aerial images (orthoimages) for the west coast of Alaska in support of coastal vulnerability mapping. Users can acess the data, as well as additional metadata, from the DGGS website: <http://doi.org/10.14509/29745>.
Overbeck, J.R., Hendricks, M.D., and Kinsman, N.E.M., 2016, Photogrammetric digital surface models and orthoimagery for 26 coastal communities of western Alaska: Raw Data File RDF 2016-1, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.
Data are in their raw format; for community-level data where vertical controls have been rigorously applied, are higher resolution, and have fewer gaps, see Overbeck and others (2016; <http://doi.org/10.14509/29548>). General data collection, processing, and accuracy assessment procedures in this release are described in a data release overview (Overbeck and others, 2017; <http://doi.org/10.14509/29744>). Horizontal and vertical accuracies of the orthoimagery and DSMs are evaluated using photo-identifiable checkpoints and elevation checkpoints collected by RECON, LLC (Overbeck and others, 2016). Accuracy assessment values reported for each alongshore segment are the mean residual between non-vegetated ground control and checkpoints and the DSM. Known, uncorrected anomalies over water bodies and cloud or snow covered areas exist throughout the project area. See accompanying report for comprehensive metadata, including discussion of the number of ground control checkpoints, accuracy statistics, and known anomalies.
Positional (horizontal) accuracy has been determined by identifying ground control points visually and comparing their location to the GPS-collected ground control, quantified as the horizontal radial root mean square error (RMSE; ASPRS, 2015). The positional accuracy at 95% confidence level was also computed according to ASPRS (2015).
Elevation data have not been vertically shifted to best fit checkpoint elevations. Instead, GPS points have been used to assess the data quality only. The approach will allow the user to make informed decisions about how to vertically adjust the DSMs to best align with local vertical datums and/or meet project accuracy requirements. Vertical accuracy was determined at the 95% confidence level according to ASPRS (2015), using checkpoints for non-vegetated and vegetated locations separately. Vertical accuracy values relative to the reported altitude datum are available in table format in the accompanying report. The accompanying report provides a table of vertical accuracy values relative to the reported altitude datum.
This data release provides continuous coastline data are in their raw format. Known issues are addressed in the accompanying reports. It is a supplement to Overbeck and others 2016; <http://dggs.alaska.gov/pubs/id/29548>, which provides high resolution for each coastal community.
The aerial photography survey was planned so flight lines and photograph frequency provided 60 percent side lap and 80 percent end lap coverage, with an average above-ground-level flying height of 1341 m, resulting in 872 photos with 0.21 m ground sample distance (GSD). Data quality have been assessed relative to checkpoints collected simultaneously with the aerial survey.
Are there legal restrictions on access or use of the data?
- 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).
- 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.
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 (firstname.lastname@example.org), 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.
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