| Summary: | Progress Code: completed Statement: Some information was sourced from TERRA. POSITIONAL ACCURACY: The Antarctic coastline has been derived mostly from Landsat 7 ETM+ imagery with a spatial resolution of 30x30m pixels. Imagery dates used ranged from 1999 to 2002, making it a consistent 'one epoch' dataset. Landsat 7 ETM+ was the preferred sensor due to its improved horizontal accuracy, as well as being the most current. Subsets of some scenes were pan-sharpened to 15x15m pixel resolution over areas requiring better definition, as in the case of areas containing numerous small islands. Images were supplied in Universe Transverse Mercator (UTM) projection and with systematic correction determined by satellite ephemeris, a satellite model based on information about spacecraft position and attitude. This information is transmitted with the imagery, or provided by the satellite operator at the time of image acquisition. It allows the imagery to be located to a limited absolute accuracy (ie. its position on the Earth). Landsat 7 ETM+ imagery was compared to various geodetic control points whose accuracy is estimated at being less than 1m. A visual estimation of their positional accuracy against Landsat 7 ETM+ showed an average accuracy of approximately 80m or less. Radarsat SAR imagery was used as complementary data to help distinguish grounding lines. Its positional accuracy ranged between 200 and 500m. Only where any other Landsat imagery did not provide the coverage required, was it used for digitising features from. No correction was applied to these images. ASTER imagery was used in one instance, where other imagery was unavailable. Its positional accuracy is estimated at around less than 50m, when compared to Landsat 7 ETM+. Each feature in the dataset contains a quality information (Q_INFO) attribute value relating to each of the source data. Features with Q_INFO values beginning with 'GA' were mapped from satellite imagery whilst those beginning with 'AAD' were extracted from existing AAD datasets. For ...
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