A Thematic Mapper (TM) is one of the Earth observing sensors introduced in the Landsat program. The first was placed aboard Landsat 4 (decommissioned in 2001), and another was operational aboard Landsat 5 up to 2012. TM sensors feature seven bands of image data (three in visible wavelengths, four in infrared) most of which have 30 metre spatial resolution. TM is a whisk broom scanner which takes multi-spectral images across its ground track. It does not directly produce a thematic map.
The Thematic Mapper has become a useful tool in the study of albedo and its relationship to global warming and climate change. The TM on the Landsat 5 has proven useful in determining the amount of ice loss on glaciers due to melting.
Landsat 7 carries an enhanced TM sensor known as the Enhanced Thematic Mapper Plus (ETM+).