What does "tone" refer to in visual image interpretation?

In visual image interpretation, "tone" specifically relates to the grayscale levels or intensity of color in an image. Tone describes the brightness or darkness of a particular area and indicates how light or dark a particular pixel or region appears in the image. This aspect is crucial because various tones can help identify different features and structures within the scene being analyzed when interpreting aerial photographs or satellite images.

The contrast in tone can reveal boundaries, highlight changes in land cover, or indicate variations in material (for instance, water appears darker than land), which is essential for effective analysis and interpretation in Geographic Information Systems (GIS). Understanding tone allows practitioners to make informed decisions about the characteristics and composition of the landscape being studied based on how the tones interact and differ across the image. This knowledge is fundamental to tasks such as land use classification, environmental monitoring, and urban planning.