Satellite Images to Allow Accurate Mapping of Penguin Colonies over Broad Regions
10.08.2010 - Flora & Fauna, Antarctic
Biologists at the Australian Antarctic Division have found a new way to develop penguin habitat maps. Basing themselves on satellite images of the extent and repartition of penguin excrement, in combination with an estimate of penguin numbers within smaller parts of the habitat, they are now able to provide accurate estimates of penguin numbers across very broad regions.
To draw the new maps, remote sensing analyst Angela Bender of the Australian Antarctic Data Center, used QuickBird satellite images covering islands along the Mawson coast. The satellite, with a spatial resolution of 60 cm, collects 'multispectral' imagery by detecting different wavelengths of light reflected by different land cover. By gradual refining through the Definiens Developer 7 software, Mrs. Bender managed to extract and analyze the poo using 'object-based image analysis' (OBIA), and classify it as 'dense’, ‘thin’ and ‘sparse'.
With these results, OBIA appears as a feasible method for separating and extracting environmental data from a small number of satellite images. While Mrs. Bender hopes to be able to incorporate spectral reflectance data from actual excrement in the field ('ground-truth data') into future analyses, she is also keen to test the usefulness of satellite imagery and aerial photos to count individual penguins based on 'texture', which could be used to identify the texture of penguin colonies when the birds are on their nests.
