In early 2009 the entire archive of the American Landsat remote sensing program will be available for free and on-line. On April 21, 2008 representatives of the U.S. Geological Survey (USGS) - the Landsat system Operator - announced that access to the archive of Landsat images, collected for over 35 years, will become free soon. Interior Secretary Dirk Kempthorne has recently comfirmed that this plan is still in force.
According to the staged project implementation, free public access to Landsat 7 imagery data is open as of October, including new images. Scenes with cloud cover less than 20% after automatic processing are ready for downloading via interface programs EarthExplorer and Glovis with minimum time delay following the acquisition.
In December the users will be able to work with Landsat 5 images, in January 2009 – with Landsat 4 and Landsat 1-5 (MSS sensor) imagery. For your reference, the Thematic Mapper — is the optical mechanical scanner, providing imaging at 30 m resolution in six bands of the visible, NIR and mid-infrared spectrum and at 120 m in long-wave IR band. In its turn the Multispectral Scanner (MSS) enables to receive images with 80 m of spatial resolution.
The input of the Landsat 35 year program into the Earth study is more than big. Please note that Landsat-1, launched back in 1972, became the first civil satellite ensuring operational transmission of middle resolution imagery via radio link. Data from six satellites of the Landsat series, thanks to democratic price and license policy, got widest distribution worldwide. Scientists and GIS specialists from 70 countries (Russia included) have long been using Landsat data in different projects and programs.
Nowadays, two Landsat satellites – Landsat-5 and -7 are still operating on orbit. However, due to a long service live of Landsat-5 satellite, launched in 1984, its equipment has a limited use. Landsat-7 images have defects due to malfunctioning in ETM+ sensor operations. The launch of the new Landsat-8 satellite (LDCM project — Landsat Data Continuity Mission) is scheduled for year 2011.
It should be noted that the principle of operational and free access to middle resolution satellite data has been increasingly promoted worldwide. Earlier Brazil and China implemented free distribution of CBERS program imagery via Internet. Now the list of available programs will be replenished by Landsat. The U.S. Geological Survey archive will become a common heritage of mankind by February 2009, when commercial distribution of Landsat data will be completely terminated. Therefore, the country supports the development of national and world geoinformation technology market.
Source : http://www.scanex.com
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