The Canada Centre for Remote Sensing (CCRS) is responsible for the acquisition and archiving of data provided by several earth observation satellites among them being Landsat, SPOT, RADARSAT or NOAA. For more details on these satellites, visite the link : http://www.ccrs.nrcan.gc.ca/ccrs/tekrd/satsens/sats/satliste.html In order to allow individuals interested in developping their own expertise in using satellite imagery, CCRS presents 17 Landsat-TM images covering all canadian capitals and a few other important cities. The 1972 inauguration of the Landsat series was done with the launch of Landsat-1 and continued until the summer of 1999 with Landsat-7. The first three satellites, launched in 1972, 1975 and 1978, were equiped with a sensor called Multispectral Scanner (MSS). It's with images acquired by this sensor that the Great Lakes mosaic available on this web site was produced. The Landsat-4 and Landsat-5 satellites, launched in 1982 and in 1984 were equiped with two sensors : the MSS and the more performing Thematic Mapper (TM). The Landsat-6 satellite was launched in 1993 but never became operational. Finally, the Landsat-7 satellite launched in 1999, is equiped with an enhanced version of the TM sensor. All details on the Landsat series can be found at the following address : http://www.ccrs.nrcan.gc.ca/ccrs/tekrd/satsens/sats/landsate.html The images acquired by the TM sensor are transmitted to ground stations in 7 spectral channels (colors), each one representing a portion of the sun's spectrum. The combination of 3 bands enables the generation of color products. TM band portion of the spectrum TM 1 0,45 - 0,52 µm (blue) TM 2 0,52 - 0,60 µm (green) TM 3 0,63 - 0,69 µm (red) TM 4 0,76 - 0,90 µm (near infrared) TM 5 1,55 - 1,75 µm (mid infrared) TM 6 10,50 -12,50 µm (thermal infrared) TM 7 2,08 - 2,35 µm (mid infrared) Taken from : Remote Sensing for Agriculture (1986) For example, the combination of bands TM 1 (blue), TM 2 (green) and of TM3 (red), generates a product in natural colors. The combination of bands TM 2,(blue), TM 3 (green) and TM 4 (red) generates a false color composite that has a spectral ressemblance to infrared color photographs. By combining spectral bands in different orders, it becomes possible to extract certain characteristics of the earth's surface as shown in the following brochures. These slightly old and out of print brochures, contain many valuable details on Landsat TM imagery and present an outlook on potential applications and the diverse permutations of spectral bands. [1) Remote Sensing for Forestry (ed. 1986)] [2) Remote Sensing for Agriculture (ed. 1986)] [3) Remote Sensing for Geologists (ed. 1986)] Technical note [More recent Landsat imagery of these and other areas and ] [LANDSAT-7 ETM+ imagery of Canada and the U.S. is available] ]from RADARSAT International Inc. http://www.rsi.ca/] 1) The images cover approximately a area of 185 by 185 km and are centered as much as possible on Canadian capitals and three other large cities. The included cities are as follows: Calgary, Charlottetown, Edmonton, Fredericton, Halifax, Iqaluit, Montréal, Ottawa, Québec, Regina, Saint-John's, Saskatoon, Toronto, Victoria/Vancouver, Whitehorse, Winnipeg and Yellowknife (the city of Vancouver is included with the Victoria image). 2) The available images are full resolution Landsat-TM acquired by the Landsat 5 satellite. All images were acquired between July 1984 and September of 1989. 3) The images are named after the city on wich they are centered 4) The images have been geocoded by RADARSAT International Inc. with ground control points extracted from topographical maps. 5) The datum is NAD 83 6) The cartographic projection used is Universal Transverse Mercator (UTM) 7) The image files generally contain 7 spectral bands (except for the .TIF files), and count 9 000 lines by 10 000 columns. Each pixel covers a ground surface of 25 metres by 25 metres. 8) The full resolution images (25 m X 25 m) are available in BSQ format. 8a).BSQ format Binary flat raster band sequential 8b)GeoTIF and TIF World Format For users of GIS and image processing software. The .TIF files are composed of TM 123 and TM 234 which correspond to natural colours (NC) and false colour infrared(IC). An automatic procedure was used for radiometric enhancements by rejecting 0,5 % of the darkest pixels and 5 % of the brightest ones-by using a linear stretch between the two cut off points on the histogram. The enhancement was sampled (calculated) under a central sub-region corresponding to 30 % of the total image. The output result has been applied to the entire image. The .TIF files are in fact data with spatial geo-referencing (GeoTIF). Some software might be able to recognize the spatial referencing of the .TIF file header. The geo-reference files .TFW (Tif World File) are also available. However, the provided thumbnails are not geo-referenced. 9)The .TIF files are available in four ground resolutions (pixel size). A coarse resolution reduces the file size and downloading time. Contrary to the more detailed finer resolution where download time will be much longer. File name (city]_25_ic.zip .TIF, compressed infrared colour, 25 m resolution (city]_25_nc.zip .TIF, compressed natural colour, 25 m resolution (city]_50_ic.zip .TIF, compressed infrared colour, 50 m resolution (city]_50_nc.zip .TIF, compressed natural colour, 50 m resolution (city]_100_ic.zip .TIF, compressed infrared colour, 100 m resolution (city]_100_nc.zip .TIF, compressed natural colour, 100 m resolution (city]_500_ic.tif .TIF, compressed infrared colour, 500 m resolution enhanced (city]_500_nc.tif .TIF, compressed natural colour, 500 m resolution enhanced (city]_thumb_ic.tif .TIF, compressed infrared colour, enhanced thumbnail (city]_thumb_nc.tif .TIF, compressed natural colour, enhanced thumbnail (city]_thumb_ic.gif .GIF, compressed infrared colour, enhanced thumbnail (city]_thumb_nc.gif .GIF, compressed natural colour, enhanced thumbnail A) City covered B) Satellite name and sensor type C) Image path and row (may include offset on the orbit) D) UTM Coordinates and zone of the 4 corners of the image file