Passive Remote Sensing
Active Remote Sensing
The LiDAR and the RADAR are examples of active remote sensing where the time delay between emission and the return is measured, the location, height, speed and the direction of the object are also established.
Advantages of Remote Sensing
There are various applications of remote sensing that includes monitoring deforestation in areas like the Amazon Basin, depth sounding of coastal and ocean depths, and glacial features in Antarctic and the Arctic regions.
The military use remote sensing in times of war to collect data in dangerous areas. It also replaces slow and costly data collection on the ground and it ensures that objects or areas are not disturbed in the process. Data collected is used to analyze and compare things like pollution, forestry, erosion, land use and weather among other uses.