Remote sensing images are sometime captured by sensors carried by a vehicle thatorbits the earth at specific speed, and at specific height it is called satellite. Normally,the orbit can be at any heights that ranges between 400 km to 36000 km.There are two types of satellite image geostationary and polar where the first coverslarge fixed area and this due to the remarkable height of 36000 km of the satellite.Example of theses satellites if the famous Geostationary Operational EnvironmentalSatellites (GOES) 35. These satellites can capture an area with swath width of7000 km and with spatial resolution lower than 4 km. The GOES images are free of charge, and they are used mainly to monitor weather and climatic conditions andnatural disasters such as tornados. The other type of satellites are polar, they are themost popular commercial and free of charge satellites where they orbit at elevation that ranges between 400 and 1000 km.
These satellites have different characteristicswhich make them more attractive for use in different scientific and military tasks.There are many examples of these satellites such as the free of charge Landsat 7and 8 which are still operational with temporal resolution that can reach 8 daysusing both satellites. These medium to high spatial resolution satellite images canbe downloaded from the USGS site 36. Another known free of charge satellitesare Modis Aqua and Terra 37 with both orbiting an image with spatial resolutionthat ranges between 250 to 1000 meters can be captured in a temporal resolutionless than one day. There are many other commercial satellites which are characterizedby having high to very high spatial resolution which ranges from 31 cm suchas Worldview-4 38 to 5 meters such as GeoEye 39. More of these commercialsatellites such as the 2.5 meters SPOT 5 40, 1.5 meters SPOT 6 and 7 41, 42, and0.5 meter for Pleiades-1A and Pleiades-1B Satellites 43.