Orthomosaic, digital surface model and point cloud of Edgeworth David Base Camp, Bunger Hills, 1st February 2025

Full description

Orthomosaic and Digital Surface Model of the Edgeworth David Camp during the de-establishment phase for Project 5219: Denman Terrestrial Campaign Operational Support 2023-2025.

The data products were produced in Agisoft Metashape Professional (2.1.3 build 18946), using 1500 nadir photographs collected by a DJI Mavic 3E RTK drone with software DJI Pilot 2. The drone had a fixed connection to a DJI D-RTK2 base station that was established over an unknown point (established in position average mode).

Drone photo positions (and exif metadata) is saved in the included geopackage.
The orthomosaic was generated using 8 ground control points surveyed on the 01st of February using an Emlid Reach RS2+ base and rover pair, with the Emlid Reach base station established over survey mark NMS238 (input coordinates 100.603656 E 66.24993453 S, 4.177m ellipsoidal height).

The resulting orthomosaic EDB_Feb_2025_orthomosaic_2.tif is in this data record. A secondary data product has also been produced, geo-referenced to the February 2023 orthomosaic using a 2nd order polynomial transformation and 12 control points (EDB_01_Feb_2025_orthomosaic_tied_Feb2025.tif, with control points saved in the file EDB_Feb_2025_orthomosaic_2.tif.points).

Control points to tie the two orthomosaics were selected from recognisable inclusions and/or protrusions on prominent boulders, and are well distributed across the terrestrial part of the scene, but not on the epi-shelf ice, due to the lack of common features present at both time points.

The orthomosaic represents a snapshot in time, as the Denman Terrestrial Campaign camp was being decommissioned. Some buildings have been removed, and at the time of image acquisition, a large amount of cargo for RTA was stored on the ice of the epi-shelf. 17 small tents (sleeping and ablutions) and 1 large mess tent are still erected. 4 red fibreglass ‘melon’ buildings, arranged around a prominent boulder, form the main Edgeworth David Base.

At the time of acquisition, 2 melons and 2 apples from the Denman Terrestrial Campaign camp had been decommissioned, and the edges of the melon sites and the helicopter pad are marked by ropes.
The point cloud was edited to remove obvious outliers, points with very low confidence (value equal to 1) and remove erroneous points from the centre of lake. The point cloud has not been classified, is in .las file format, and consists of 141,409,860 points.
Project coordinate system is WGS 84 / UTM Zone 47S (EPSG::32747). Project positioning errors calculated by Agisoft Metashape from the 8 ground control points are 3.5 and 3.7 cm in X and Y, and 21.2 cm in Z dimension (RMSE). DEM is in height above ellipsoid.

This dataset is part of a time series. Another mapping mission was conducted 3 days after this one.

See also metadata records for preceding time points:
22 December 2022 http://dx.doi.org/doi:10.26179/cc4z-h403
06 February 2023 http://dx.doi.org/doi:10.26179/146h-9b03

Lineage

Progress Code: completed

Statement: The Digital Surface Model is in height above ellipsoid. The is likely a systematic height offset due to the use of 4.177 m as the base height over survey mark NMS238.

Notes

Purpose
Supporting information for sampling associated with project 4622: A Cleaner Antarctica, and timepoint comparison for Denman Terrestrial Campaign Operational Support.