Satellite Imagery
Definition
Satellite imagery refers to images of Earth or other planets that are collected by imaging satellites operated by governments and businesses around the world. These pictures or photographs are captured by sensors on satellite platforms orbiting the earth and showcase infrared as well as visible light to observe and measure different aspects of the earth's surface.
Satellite images are often used in meteorology, geography and geology studies, farming, espionage, environmental studies, oil exploration, and more. They serve as a valuable resource for scientific research, environmental monitoring, resource management, and in a wide range of geospatial and geographical studies.
What is Satellite Imagery?
Satellite imagery involves the snapping of images from an orbiting satellite looking down on Earth or other planetary bodies. These images, like photographs, can be in visible light or captured in other areas of the electromagnetic spectrum. The images are mostly digital and can be processed to enhance visibility or to highlight certain features. Satellite imagery can also be mosaicked into larger scenes or mapped onto a geometric grid to give coordinates to the picture elements (pixels).
The images obtained are then processed to remove distortions caused by the motion of the satellite and the earth's curvature and rotation. Information obtained from satellite imagery is used in many applications, such as weather prediction, land use planning, wildlife habitat monitoring, and natural disaster impact assessment among others.
Satellite images can range from low-resolution images that cover large swaths of the Earth's surface, to high-resolution images that can focus on a small area in great detail. Most commercial satellite images are in the range of one meter to 60 centimeters resolution, meaning one pixel in the image represents a square meter or less on the ground.
FAQs
What are the types of Satellite Imagery?
Primary types are passive and active imagery. Passive sensors detect natural radiation emitted or reflected by the object or surrounding area being observed. In contrast, active sensors use internal stimuli to collect data about the earth, such as radar.
How is Satellite Imagery used?
The use cases of satellite imagery are diverse. They are used in weather forecasting, surveillance, navigation, research, mapping and exploration of natural resources, environmental monitoring, agriculture, disaster management and relief, and in many fields of study such as geography, geology, and meteorology.
Are Satellite Images Real-time?
While there certainly are satellites that can capture and transmit images near real-time, most commercially available satellite imagery is on a delay. This delay can be due to the time it takes for the satellite to pass over the location, the time needed to process the images, and the type of satellite capturing the image.
How accurate are Satellite Images?
Accuracy of satellite images depends on the resolution, timestamp, positional accuracy, atmospheric conditions, sensor quality, and image processing techniques. High-resolution satellites can provide images with details up to 30cm on a side per pixel, although these are generally not available for public use.
