Thematic Mapper
The Thematic Mapper (TM) is a supported by the Landsat -4 and -5 satellites opto - mechanical system for the detection of remote sensing data in the research field of remote sensing, Enhanced Thematic Mapper ( ETM ) extension with Landsat 7th
Spatial resolution
The system is based on an array of 100 spectral detectors which record by an oscillating mirror, the reflected signals from the surface.
In this case the spectral channels 1 to 5 and 7 per channel 16 form a scanning array spectral detectors. There are 4 detectors per row for the channel 6.
About 6300 measurements are performed per mirror rotation. One line corresponds to 185 km on the Earth's surface. 185 km / approx 6300 measurements = 30 meters per pixel in the row.
A scanning array consists of 16 detectors and is 480 meters away, this results in 30 meter per pixel in the row.
A pixel of the channels 1-5, and 7 is the radiation intensity from an area of 30 meters x 30 meters.
A pixel of the TIR channel 6 depicts the radiation intensity of an area of 120 meters x 120 meters.
Spectral resolution
Enhanced Thematic Mapper ( ETM)
Landsat 6 was equipped with a ETM, which was not used due to the loss of the satellite. The ETM of Landsat-7 system provides since 2003 because of a mechanical problem only high-resolution data within a strip 25 km wide.
In addition to TM, ETM had a panchromatic band 0.5-0.9 microns with 15 m spatial resolution ( Volume 8 ), ETM with a spatial resolution of 60 m in the thermal band.
This provides for ETM following channels are available ( wavelengths in microns): 0:45 to 0:52, 0.52-0.60, 0.63-0.69, 0.76-0.90, 1.55-1.75, 2:08 to 2:35 with 30 m resolution, 10.4-12.5 (thermal band) and a panchromatic band 0.5-0.9 with 15 m spatial resolution ( band 8).
Radiometric resolution
The TM- detectors have a resolution of 8-bit to represent 256 different shades of gray.
The right image sequence data shows excerpts from the 7 channels of remote sensing data of the Thematic Mapper on Landsat 4-5 TM satellite. The inset shows the Polish city of Krakow and its surroundings.
The original data sets of the 7 channels of the Thematic Mapper have a data volume of around 450 megabytes.