Torres Strait clear sky, clear water Landsat 5 satellite composite (NERP TE 13.1 eAtlas, AIMS, source: NASA)

Brief description

This dataset is a composite of Landsat 5 satellite imagery to produce a cloud free, clear water seamless image of the Torres Strait region. This image includes some of Cape York and PNG, in particular the Fly river. This composite shows clear imagery for marine areas, in particular reefs, larger islands and sand bars.

This image has a resolution of approximately 30 m and a positional accuracy of better than 50 m.

There is a new similar dataset based on higher resolution Sentinel 2 imagery: Lawrey, E. (2022). Torres Strait Sentinel 2 Satellite Regional Maps and Imagery 2015 – 2021 (AIMS) [Data set]. eAtlas. https://doi.org/10.26274/3CGE-NV85

This composite is made from 8 Landsat scenes. Images in each scene were selected by trawling through the entire archive of Landsat 5 to find the clearest two to three clearest images. The preference for these images was that they needed to be as cloud free as possible, be at low tide and for the water to be as clear as possible. The final images used range from 1993 - 2009.

The selected images were converted to true colour, corrected for sun glint, high level thin clouds and haze. The two or three images for a scene were then blended together in Photoshop using feathered masks to remove clouded areas. The images were then colour and tonally corrected to match neighbouring scenes. The scenes were then blended by copying cropped feathered versions of the neighbouring scenes. The resulting images for each scene were then masked to create a clean "no data" boundary around the image so that mosaicking would not introduce any visual artefacts.

The scene images were then mosaicked together into a single image using gdalwarp. The final image was then reprojected using gdalwarp and finally trimmed and compressed using gdal_translate.

Lineage

Statement: All imagery was derived from Landsat 5 imagery.

Notes

Purpose
This dataset was created to provide a clear view of the marine areas in the Torres Strait as no existing online mapping products (including Google) did a good job of this at the time the dataset was developed.