The instrumental recording and interpreting of various portions of the electromagnetic spectrum from planetary or satellite surfaces. This information is obtained mostly in digital form, either from spacecraft or telescopically. A common form is a photographic image in the visible portion of the spectrum. ‘Multispectral imaging’ consists of simultaneous recording, typically of four or more spectral bands ranging from the visible to infrared wavelengths. ‘Image intensifying’ is the enhancement of the image by computer processing. See remote sensing.