digital surface model: DSMs represent surface elevations of all surfaces, including vegetation, vegetation-free land, bridges, buildings, and so on. The DSM is a single-band, 32-bit float GeoTIFF file, with a ground sample distance (GSD) of 0.19 m. The "No Data" value is set to -32767.
Wikstrom Jones, Katreen, Wolken, G.J., and Hendricks, M.D., 2019, Photogrammetry-derived digital surface model and orthoimagery of Valdez Glacier ice-dammed lake, Valdez, Alaska, October 12, 2016: Raw Data File RDF 2019-6, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.Online Links:
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.
These data products were funded by the City of Valdez and Alaska Department of Natural Resources, Division of Geological & Geophysical Surveys. We thank Alpine Air for their aviation expertise and contribution to these data products.
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The data release is one of a series of Alaska Division of Geological & Geophysical Surveys (DGGS) publications to present elevation data collected prior to and after the annually recurring glacial lake outburst floods (GLOFs) at Valdez Glacier. The goal is to provide information for the City of Valdez to better understand the complex nature of these phenomena.
Wikstrom Jones, Katreen, Wolken, G.J., Whorton, E.N., and Hendricks, M.D., 2019, Photogrammetry-derived digital surface model and orthoimagery of Valdez Glacier ice-dammed lake, Valdez, Alaska, October 15, 2014: Raw Data File RDF 2019-2, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.Online Links:
Wikstrom Jones, Katreen, and Wolken, G.J., 2019, Valdez Glacier ice-dammed lake: June 2018 glacial lake outburst flood: Preliminary Interpretive Report PIR 2019-4, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.Online Links:
Wolken, G.J., Arendt, A.A., and Rich, J.L., 2015, Bathymetry of Valdez Glacier lake: Raw Data File RDF 2015-1, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.Online Links:
Wolken, G.J., and Wikstrom Jones, Katreen, 2017, Valdez Glacier ice-dammed lake: June 2017 glacial lake outburst flood: Preliminary Interpretive Report PIR 2017-4, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.Online Links:
The DSM and orthoimagery have been visually inspected for data errors such as pits, border artifacts, and shifting. The end-user should be aware that pits and peaks are present in areas of some small water bodies, such as lakes and ponds, and that DSM data have not been hydro-flattened in these areas.
The average camera location error was 0.12 m in the X direction, 0.12 m in the Y direction, and 0.14 m in the Z direction, with a combined XY error of 0.17 m and resulting total error of 0.22 m.
Nearby CORS stations were used as the vertical and horizontal control. GNSS data were collected and processed in WGS84 (G1674) using the WGS84 ellipsoid. The base station position was corrected using the NGS Online Positioning User Service (OPUS) with IGS08 (EPOCH 2015.6162). Camera coordinates were converted to the North American Datum 1983 (NAD83; 2011) European Petroleum Survey Group Well Known Identification Number (EPSG) 6335 and the North American Vertical Datum of 1988 (NAVD88; Geoid12A; EPOCH 2010.00) using the National Geodetic Survey (NGS) VDatum tool (version 3.3).
The aerial photographic survey resulted in approximately 60 percent side lap and 80 percent end lap coverage, with an above-ground-level flying height of 1,100-2,000 m, and resulted in 818 photos with 0.096 m per pixel ground resolution. The total area surveyed was approximately 11 km2. This data release is complete.
Nearby CORS (National Geodetic Survey NGS - Continuously Operating Reference Stations) stations were used as vertical and horizontal control.
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.
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RDF 2019-6
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: | digital surface model |
|---|---|
| Network links: |
<http://doi.org/10.14509/30200> |
(907)451-5020 (voice)
(907)451-5050 (FAX)
dggspubs@alaska.gov