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, area or phenomenon under investigation. As you read these word, you are employing remote sensing.
AN elementary textbook is much concerned with the fundamentals of a subject and these do not change with time. In this respect the second edition of our book •has been little modified. In every other it is much altered for the subject has advanced greatly since we gathered together the material for the original version. The changes have been brought about mainly by developments in …