LANDSAT

The American series of Landsat satellites has provided high quality multispectral data since 1972. Landsat 1-3 had a MSS (Multispectral Scanner) sensor and a RBV Camera (Return Beam Vidicon). Landsat 4 and 5 have an MSS and a TM (Thematic Mapper) sensor on board.

The resolution of the MSS, TM and ETM sensors are as follows:

  MSS

Band	Wavelength	Resolution
1	0.5-0.6um (green)	80 m
2	0.6-0.7um (red)	80 m
3	0.7-0.8um (red to near infra-red)	80 m
4	0.8-1.um (near infra-red)	80 m

  TM

Band	Wavelength	Resolution
1	0.45-0.52 um (visible)	30 m
2	0.52-0.60 um (visible)	30 m
3	0.63-0.69 um (visible)	30 m
4	0.76-0.90 um (near infra-red)	30 m
5	1.55-1.75 um (infra-red)	30 m
6	10.4-12.5 um (thermal near infra-red)	120 m
7	2.08-2.35 um (infra-red)	30 m

 

MSS data is only available as full scenes whereas TM data can either be purchased as a full scene, quadrant or a mini scene but this can differ depending on where the data is processed.

Applications for the use of Landsat data include geology, agriculture, cartography, coastal mapping and land use areas.

SPOT

The resolution of the bands are as follows:

Scene sizes are typically 60x60km (vertical viewing) or 60x80km for oblique viewing. The optical imaging instruments (HRVs) are steerable to either side of the ground track - east to west - by up to 27 degrees. Stereo images can therefore be acquired which are ideal for topographic mapping and the generation of digital elevation models (DEMS).

Typical applications for the use of Spot imagery are cartography, agriculture, environment, planning, military and forestry.

IRS

IRS-1C is the latest in a series of Indian satellites and was launched on 28 December 1995. It has 3 sensors on board:

Scene Sizes:

The applications the data may be used for include crop studies, land use mapping/planning, cartography and terrain mapping, water management, forestry and geological and geomorphological studies.

IKONOS

The IKONOS satellite launched by Space Imaging in September 1999 provides the highest resolution data commercially available.

The applications for this data are boundless:  in particular, it will be used for large scale mapping, creating precise height models for e.g. micro-cellular radio, and for every application requiring the utmost detail from areas which are inaccessible for aerial photography.

JERS

The Japanese Earth Resources Satellite was launched in February 1992 and carries 2 sensors - the Optical and Synthetic Aperture Radar (SAR).

The optical sensor has 8 spectral bands:

The 4 SWIR bands are currently not operational.

The third band in the NIR range is duplicated with a forward looking (15.3 degrees) sensor of the same frequency (known as band 4), giving excellent acquisition conditions for stereo pairs.

The nominal size of a scene is 75x75km.

Typical applications for JERS optical data include water quality, vegetation surveys, environment and mapping.

Russian Satellites

Data from the cameras offer a resolution from 2-20m which provides a bridge between satellite and aerial photography.

The Russian Data can be used for a variety of applications depending on the resolution of the imagery. Applications include military applications, cartography, mapping and large scale measurement and monitoring of agriculture, forestry, coastal zones, ice and snow.

Radar Data

With its cloud penetration, Synthetic Aperture Radar (SAR) can be used for mapping areas otherwise difficult to image using optical sensors. Sensitive to surface roughness, SAR provides information on large scale variations such as topography and small scale roughness such as ripples or waves on the surface of the water. There are a number of radar satellites available.

ERS

This series of satellites is the first to be launched in Europe. They not only have a core set of Active Microwave Sensors but they are supported by additional complementary instruments.

The Active Microwave Instrument comprises 2 separate radars - SAR and a Wind Scatterometer. These radar instruments enable 3 modes of operation: image mode, wave mode and wind mode.

The other instruments on board include the Along Track Scanning Radiometer (ATSR); and the Radar Altimeter.

Applications for use of ERS data include oceanography, glaciology, climatology, sea state and ice conditions, oil slick monitoring and land use.

RADARSAT

This satellite was launched in November 1995. It has 7 different beam modes and a number of different beam positions within these. The various beam modes/positions are as follows:

Typical applications for the use of Radarsat data are agriculture, cartography, land use, oceans, sea ice, coastal zone and geology.

JERS

The Japanese Earth Resources Satellite was launched in February 1992 and carries 2 sensors - the Synthetic Aperture Radar (SAR) and the Optical.

The SAR sensor has a spatial resolution of 18m and the scene size is 75x75km.This sensor is primarily used for resource exploration as well as national land and topographical and geological surveys.