There have been instances in the past where on-ground validation for certain satellite images did not occur, and when crucial decisions were made based on this inaccurate data there were very serious consequences. Even if a system is able to produce high-resolution images, they must be validated in-person on the ground to ensure accuracy. Google Earth compiles images from various sources, from satellites in geosynchronous orbit that snap low-resolution photos from tens of thousands of miles above Earth, to satellites. It should be noted that satellite images can only be as good as their resolution. The varying features on the Earth also possess different albedo levels, which is then reflected in the way satellites process the energy and differentiate between objects in accordance to the way they react to radiation. Active sensors – on the other hand – require a significant amount of energy, as it actually emits radiation and analyzes it once it has been reflected back from the Earth’s surface. Passive sensors require no energy as it collects radiation emitted from the Sun and reflected by the Earth’s surface. There are two types of sensors to make note of and these are passive sensors and active sensors. These devices make use of sensors that collect electromagnetic radiation being reflected from the Earth’s surface. Satellite Imagery is captured using satellites and a variety of other aircraft-based sensor technologies such as drones.
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