The most commonly used earth's resource satellites are - Landsat series of USA, SPOT satellite series of France, and IRS series of India. These bear different types of scanners, viz,Multispectral Scanner (MSS), Thematic Mapper (TM),Panchromatic (PAN) scanner, High-Resolution Visible (HRV) scanner, Linear Imaging and Self Scanning (LISS) system, Wide Field Scanner (WiFS), etc. NOAA, NIMBUS, GOES Meteos are the most commonly used meteorological satellites.