Remote sensing is the science and art of obtaining information about an object, area, or phenomenon through the analysis of data acquired by a device that is not in contact with the object.

It is the utilization at a distance (as from aircraft, spacecraft, or satellite) of any device for gathering information about the environment. Remote Sensing makes use of devices such as a camera, laser, light, or radar to gather data.

The basic unit used in remote sensing is the wavelength of reflectance which is measured in nanometers (nm). This kind of data collection normally makes use of the emitted or reflected electromagnetic radiation of the examined object in a certain frequency domain (infrared, visible light, microwaves). This is possible due to the fact that the examined objects (plants, houses, water surfaces, air masses ...) reflect or emit radiation in different wavelengths and in different intensity according to their current condition. These levels emitted by different objects are commonly known as their "spectral signature".

Remote sensing generally has several basic problems:

• Scaling
• Alignment
• Resolution
• Interpretation
• Archiving