Abstract:
This dataset includes a 10 metre resolution digital elevation model (DEM) of the Whitney Point area of the Windmill Islands, Antarctica and an orthophoto created using the DEM.
The data are stored in the UTM zone 49 map projection. The horizontal datum is WGS84.
The data were created by Robert Anders, Centre for Spatial Information Science, University of Tasmania, Australia to support the postgraduate research of Phillipa Bricher into the nesting sites of Adélie Penguins.
See a related url below for a map showing Whitney Point.
The DEM was derived using photogrammetry techniques from aerial photography flown on 5/03/03.
The photography used was from the Australian Antarctic Data Centre's aerial photography collection: Film ANTC1216 Run 15 - Frames 2, 3.
... See a related url below to search the the Australian Antarctic Data Centre's Aerial Photography Catalogue.
Ground control for the photography was measured by Prof Peter Morgan, in the 2004/2005 season using differential GPS.
Ground Control Limitations: Results from the post processing of the GPS data indicate that the average precisions of the ground control coordinates were:
Horizontal 0.80 m plus or minus 0.81 (s.d.) (range 0.07 – 1.61 m) Vertical 0.76 m plus or minus 0.28 (s.d.) (range 0.51 – 1.15 m)
In addition to the accuracy of the GPS coordinates, there is an error associated with the identification of ground control points, estimated to be in the plus or minus 5 m range. This error is primarily due to a small number of ground control, that are poorly defined natural targets.
Data accuracy: The stated accuracy of the DEM (see below) is limited to areas of terrain that is not covered by snow or ice. Areas covered by snow or ice were only edited to the extent of removing significant gross errors by using a linear interpolation algorithm based on surrounding elevation data. This problem is due to difficulties in not being able to view non-textured surfaces in stereo, and consequently not being able to edit the DEM. Similarly given the transient nature of snow/ice, this data is unreliable.
Similarly, areas that have had high concentrations of penguins also exhibit a non-textured surface. Given the small relative size difference to the snow/ice areas, elevation data in these areas would be expected have a greater reliability.
Results from the absolute orientation using the 4 most reliable ground control points, indicate an average error of 6.59 m plus or minus 0.58 s.d.
Absolute height of the DEM remains uncertain, given the accuracy of the ground control, and in particular the position of the sea-level boundary.
In summary, subject to the explanations and limitations noted above: Orthophoto – The planimetric location of a well defined point is expected to be within 8 m of its true value (90% certainty).
DEM – The height associated with a planimetric position for regions unaffected by snow, ice, or penguin shit is expected to be within 2 m (90% certainty) of its true value.
Access Constraints
The DEM is available for download. To obtain a copy of the orthophoto (1.4 Mb) log a request with the Australian Antarctic Data Centre. See related urls below.
Robert Anders should be acknowledged as the creator of this data. The Australian Antarctic Data Centre should be acknowledged as having provided this data. The data are available for non-commercial use only.
This
"A digital elevation model (DEM) and orthophoto of the Whitney Point area of the Windmill Islands, Antarctica" is licensed under a Creative Commons Attribution 3.0 Unported License.
