Landsat Data
The Landsat series of American satellites has provided high quality multi-spectral data since 1972. Over the years, millions of scenes have been acquired to form a world-wide archive of Earth observation data.
Landsat 7 was launched successfully on 15th April 1999 and has enhanced features, including a 15 metre panchromatic band. It is an ideal, multi-purpose, cost-effective tool for a huge range of applications.
Landsat 1 - 3 carried a MSS (multi-spectral scanner) sensor and a RBV (return beam vidicon).
Landsat 4 and 5, launched in 1982 and 1984 respectively, have a MSS and TM (thematic mapper) sensor on board.
The satellite orbits at an altitude of 705Km. A full size Landsat MSS or TM scene covers an area of approximately 185Km by 175Km. The swathe of the sensor restricts the maximum width, and the contiguous orbit data is then divided up into nominal scenes. Digital products include raw and system corrected data.
Landsat 7 ETM+ Data
The ETM+ sensor on Landsat 7 has a number of enhanced features, including:
- New panchromatic band with 15 metre spatial resolution, co-registered with the multi-spectral bands
- Thermal infra-red band 6 has increased resolution from 120m to 60m, and now has two gain settings
- Worldwide data - the solid state tape recorder can collect 100 images per day from anywhere in the world
A summary of the band information is contained in the table below.
| Band Width | Spatial Resolution | |
|---|---|---|
| Band 1 | 0.45 - 0.52μm (blue) | 30 metres |
| Band 2 | 0.52 - 0.60μm (green) | 30 metres |
| Band 3 | 0.63 - 0.69μm (red) | 30 metres |
| Band 4 | 0.75 - 0.90μm (near infra-red) | 30 metres |
| Band 5 | 1.55 - 1.75μm (infra-red) | 30 metres |
| Band 6 | 10.4 - 12.50μm (thermal infra-red) | 60 metres |
| Band 7 | 2.08 - 2.35μm (near infra-red) | 30 metres |
| Band 8 | 0.52 - 0.90μm (green - near infra-red) | 15 metres |
Landsat 4 & 5
Landsat 4 and Landsat 5 data are essentially similar to the 30 metre spectral bands of Landsat 7 ETM+ data. Band 6 has a resolution of 120 metres. Landsat 4/5 data is typically more noisy than ETM+ data.
The USGS, who operate these satellites, have now decommissioned them and no further acquisitions are planned.