Landsat-7 ETM+ as an observatory for land cover: Initial radiometric and geometric comparisons with Landsat-5 Thematic Mapper

The Landsat-7 ETM+ sensor offers several enhancements over the Landsat-4,5 Thematic Mapper (TM) sensor, including increased spectral information content, improved geodetic accuracy, reduced noise, reliable calibration, the addition of a panchromatic band, and improved spatial resolution of the thermal band. In this paper, we present some initial comparisons between Landsat-5 TM and Landsat-7 ETM+ imagery in order to quantify these improvements. We find that the ETM+ continues the record of TM observations, and, in many respects, substantially improves upon the earlier sensor. Specific improvements include lower spatial noise levels, improved information content, and geodetic accuracy of systematically corrected products to 50–100 m. These improvements are likely to have significant benefits for land-cover mapping and change detection applications.