The Landsat satellite
has a repeat cycle of 16 days but its sensor is fixed to view
vertically and so cannot be programmed to image scenes from
different orbits.
The Landsat image
size is 185x170 km. The satellite has two sensors, Thematic
Mapper (TM) and Multispectral scanner (MSS). Delivery of archived
digital data takes approximately 2 weeks. Costs exclude VAT
and carriage.
Thematic
Mapper (TM)
Landsat TM data
has 30m resolution in six spectral bands ranging from Blue
to Middle Infrared and 120m resolution in one Thermal Infrared
band. TM data has been acquired since 1982. Due to a lack
of onboard recording capacity TM data cannot be acquired in
some parts of the world.
A full scene is
185x170 km and can be shifted N-S along an orbital track.
Images are available in 7 band digital format. Click
here to see if we already hold your image. The largest
standard scale recommended for Landsat TM is 1:100,000.
Landsat TM is particularly
useful for detecting very subtle surface colour information.
Because of the large number of spectral wavebands available,
bands can be chosen that suit the intended application and
bring out information not visible to the eye. Specially priced
3 band scenes are available, for hardcopy prints or map products
only.
The Landsat 7 satellite
was launched on the 15th April 1999, continuing the data-gathering
mission of previous TM sensors with the new Enhanced Thematic
Mapper instrument (ETM+). This sensor is similar to TM, but
has an additional greyscale (Panchromatic) band which collects
imagery at 15m resolution, and also a Thermal-Infrared band
with resolution improved to 60m. Furthermore, the ETM+ instrument
benefits from an on-board recording facility, which means
that for the first time on a Landsat satellite coverage can
be obtained at low cost over every part of the world.
Landsat MSS data
has 80m resolution in four spectral bands ranging from green
to near infrared and has been acquired since 1972. Each scene
covers 185x170 km. Digital images cost US$200. The largest
recommended scale for Landsat MSS is 1:250,000 scale. Landsat
MSS is useful for covering large areas with low cost medium
resolution colour data.
Thematic
Mapper (TM) 
Multi
Spectral Scanner (MSS)