Question

Spectral signature of an object in a satellite image does NOT depend on the

• A. \( \text{Season of the year} \)
• B. \( \text{Wavelength of electromagnetic spectrum} \)
• C. \( \text{Swath width of the satellite} \)
• D. \( \text{Reflectance value from the object} \)

Hint:

Think of the spectral signature as the object's 'fingerprint' in terms of how it reflects light, which is independent of how wide an area the satellite sees.

Answer 1

The Correct Option is C

The spectral signature of an object, which is the pattern of its reflectance or emittance across different wavelengths, is influenced by several factors: \begin{itemize} \item Season of the year: Vegetation phenology, soil moisture, and sun angle variations due to seasons can alter an object's spectral response. \item Wavelength of electromagnetic spectrum: Spectral signatures are inherently defined as a function of wavelength. Different materials interact differently with different parts of the spectrum. \item Reflectance value from the object: The spectral signature is essentially a plot of reflectance (or emittance) versus wavelength. \end{itemize} The swath width of the satellite, which is the width of the area on the ground that the satellite sensor can image in a single pass, does not directly affect the fundamental spectral reflectance properties of an object itself.