Sensors and Their Specifications

S K Diwakar

Thematic Mapper (TM)

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 meter 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.

Band Specification

Band Wavelength

(µm)

Resolution

(m)

Swath

Width

(km)

Revisit time

(days)

Band 1 (Blue) 0.45 to 0.52 30 185 16

Band 2 (Gr) 0.52 to 0.6 30 185 16

Band 3 (Red) 0.63 to 0.69 30 185 16

Band 4 (NIR) 0.76 to 0.9 30 185 16

Band 5 (SWIR) 1.55 to 1.75 30 185 16

Band 6 (TIR) 10.4 to 12.5 120 185 16

Band 7

(SWIR)

2.08 to 2.35 30 185 16

Sensors and Their Specifications

S K Diwakar

Enhanced Thematic Mapper (ETM+)

ETM+ is similar to TM, but has a higher spatial resolution thermal channel

and includes a new panchromatic channel. These satellites have a polar,

circular, sun-synchronous 705-km orbit with a 16-day repeat cycle. The TM

swath width is 185 km.

Band Specification

Band Wavelength Region (µm) Resolution (m)

1 0.450-0.515 (blue) 30

2 0.525-0.605 (green) 30

3 0.630-0.690 (red) 30

4 0.750-0.900 (near-IR) 30

5 1.55-1.75 (mid-IR) 30

6 10.4-12.5 (thermal-IR) 60

7 2.08-2.35 (mid-IR) 30

PAN 0.52-0.90 15