Remote sensing is a technique used to derive information about the physical,
chemical, and biological properties of objects without direct physical contact
 Information is derived from measurements of the amount of electromagnetic radiation
reflected, emitted, or scattered from objects.
 Figure 9.2 shows the spatial and temporal characteristics of commonly used remote
sensing systems and their sensors
 Resolution is a key physical characteristic of remote sensing systems.
 Spatial resolution refers to the size of object that can be resolved and the most usual
measure is the pixel size.
 Spectral resolution refers to the parts of the electromagnetic spectrum that are
measured.