Remote sensing is the acquisition of information about an object or phenomenon without making physical contact with the object and thus in contrast to on-site observation, especially the Earth. Remote sensing is the evaluation of information on an object or phenomenon without any physical contact with the particular object and therefore unlike in situ observation. Remote sensing generally refers to the use of aerial sensor technologies to detect and classify objects on Earth using propagated signals. Active remote sensing means when a signal is first transmitted from an aircraft or satellites and passive means when information is recorded. The main journals are scholarly peer-reviewed journals. These provide a high quality, meticulously edited and timely publication to meet the pressing needs of the scientific community. These journals are indexed with all their noted citations.