Vestfold Hills Lake Bathymetry

Brief description

This data set contains the most recent bathymetric contour data for some of the lakes of the Vestfold Hills.

Lake depth data (all data except Ellis Fjord) was collected from echo sounding records of courses plotted on enlarged aerial photographs (HighJump photography). Courses were straight lines from shoreline features identified on both the photographs and in the field. Depths were plotted on the enlarged photographs and contours drawn between marked depths. Accuracy for position -+ 5 metres. Accuracy for depth -+ 2 metres.

Ellis Fjord was sounded in winter from the ice surface. Painted 44 gallon drums were set up on hills on both sides of the fjord. When a depth position was recorded by weighted line through an ice hole, a theodolite (T2) at the hole was sited to several drums on the land. These triangulations were used to determine the position of the depth in the fjord. Accuracy for position -+ 2cm. Accuracy for depth -+ 2 metres.

The water bodies included in the dataset are:

Ace Lake
Burton Lake
Club Lake
Deep Lake
Ellis Fjord
Lake Abraxas
Lake Anderson
Lake Jabs
Lake Lebed
Lake Nicholson
Lake Stinear
Lake Watts
Oblong Lake
Organic Lake

See also the following maps at the provided links:
Map 15618: Deep Lake Marine Profile - Plan and Longitudinal section (Sheet 2 of 2)
Map 15621: Club Lake Marine Profile – Plan and Longitudinal Section (Sheet 1 of 2)
Map 15622: Lake Jabs, Saline Lake Profiles – Plan and Longitudinal Sections

Lineage

Progress Code: completed

Statement: The data set was derived from numerous hardcopy maps, which involved four main processes. These were:

1, The hard copy maps were scanned and saved as TIF images. These images were then loaded into Corel Trace and the lines traced creating a DXF file. The DXF files were checked using Microstation for small tracing errors such as dangle arcs, and corrected where necessary.

2, The images of the hard copy maps were geo-referenced using Microstation and a similarity transformation. The images were fitted to the Vestfold Hills lake edge data using a visual best-fit approach with varying results.

3, Using the geo-referenced images, the DXF files were imported, and a similarity transformation was performed to fit the line data to the geo-referenced image. Once geo-referenced, all contour lines had their respective heights tagged.

NOTE: For the data for Ellis Fjord two hard copy maps were used. The first map contained the contours for the whole fjord. The second map contained the most recent data for the head of the fjord. The data from the two maps were merged using Microstation after being geo-referenced. For more information see DQI 181.

4, The contour line data were then imported into the Arc/Info coverage format (utilising regions) and structured to conform with the Australian Antarctic Division's Spatial Data Model. This spatial data model has since been superseded by the SCAR Feature Catalogue (refer to link below) and the attribute data have been reformatted accordingly.

Each bathymetric contour and bathymetric area feature has a DQI number. Use these DQI numbers (172,176-178,181,186-194) to search for Quality Information Records about the features (refer to link below). Enter the DQI number as the Qinfo id and start the search. The information includes the original hard copy map name and the estimated accuracy of the data.