Authors / CoAuthors
Unknown
Abstract
The Landsat series of satellites commenced acquiring remotely sensed data with the launch of Landsat 1 in 1972. Landsat satellites travel at an altitude of 705 kilometres and provide coverage of the entire globe every 16 days. Landsat 7, launched on 15 April 1999, carries the Enhanced Thematic Mapper Plus (ETM+). As the name suggests, the ETM+ sensor is similar to the TM sensor but has some added features. It provides imagery in the same seven spectral bands as the TM sensor with 30 metre resolution, but has an added panchromatic band with 15 metre pixel resolution. ETM+ also has an enhanced thermal band with a 60 metre resolution. Its ground swath is 185 kilometres. A full scene is approximately 184 kilometres by 172 kilometres. The archive of ACRES products includes ETM+ data from 6 July 1999 onwards.
Product Type
dataset
eCat Id
47906
Contact for the resource
Custodian
Owner
Point of contact
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
Keywords
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- Satellite ImageryLandsat
- ( Theme )
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- satellite imagery
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
Publication Date
2003-06-17T00:00:00
Creation Date
Security Constraints
Legal Constraints
Status
Purpose
Maintenance Information
continual
Topic Category
imageryBaseMapsEarthCover
Series Information
Lineage
The Landsat ETM+ data set is acquired by earth orbiting remote sensing satellites. These satellites carry two types of sensor systems known as "active" and "passive". A "passive" system generally consists of an array of small sensors or detectors which record (as digital numbers) the amount of electro-magnetic radiation reflected and/or emitted from the Earth's surface. The Landsat ETM+ is a passive system. The digital data acquired by the satellites are transmitted to ground stations and can be used to reconstitute an image of the Earth's surface not too dissimilar to an aerial photograph. Data are received through the ACRES antenna at the Data Acquisition Facility at Alice Springs enabling coverage of the Australian landmass. The recorded data are air-freighted daily to the Data Processing Facility in Canberra where it is catalogued and archived. Data are recorded and archived by path, or swath, allowing coverage of any region in the path to be extracted by its geographical coordinates. If the region of interest extends across two adjacent paths the appropriate data set from each path will need to be extracted. Because of the orbital parameters of the satellite, adjacent paths are not acquired sequentially and information from each path may differ according to the time delay between the two passes. To assist cataloguing and ordering, a path is segmented into individual scenes the length of each scene being the same as the path width. Each scene can be related to geographical coordinates using the Path/Row reference system. The Path is the number of the satellite swath (east to west) across Australia and the Row is the number of the scene south of the equator. Diagrams and formulae are available to assist in relating geographical coordinates to the satellite scene Path/Row coordinates. Each scene acquired by ACRES is sub-sampled and produced in its Digital Catalogue access to which is available through the WWW. Data are provided as hard copy photographic data products, or as digital data products which can be viewed and manipulated on a variety of software systems. However, the data transmitted to Earth from an Earth observation satellite are in a form unsuitable for use by customers so ACRES processes this raw data in varying degrees to produce products suitable for use by clients. ACRES only processes the data after a client has placed an order for a specific product. This is due to the large quantities of data received from a satellite and the large range of product options available.
Parent Information
Extents
[-90.0, -9.0, 45.0, 168.0]
Reference System
Spatial Resolution
Service Information
Associations
Source Information
Source data not available.