3.1. Remote sensing measurements

Remote sensing is defined as the scientific and technological discipline of obtaining information about objects/features on the earth’s surface without being in direct contact with them. This information is typically gathered from aircrafts or satellites equipped with sensors (e.g., cameras) that record electromagnetic (EM) radiation from objects on the earth’s surface. The radiation recorded by Earth Observation (EO) sensors can be placed in the EM spectrum, which describes the range of all possible frequencies/wavelengths of radiation. Only a portion of the EM spectrum is visible/detectable by the human eye (i.e., the visible portion). Other portions of the spectrum include infrared, microwave and radio waves, all of which are not detectable by the human eye. To gather information, EO sensors are designed to make measurements in specific portions/divisions of the EM spectrum.