Tricks and tips for everyone


How do you convert DN to reflectance in ENVI?

How do you convert DN to reflectance in ENVI?

Click on the Reflectance radio button and enter an output file name. For ENVI Standard, select from the Toolbox | Radiometric Correction | Radiometric Calibration. Select the optical data file and the Radiometric Calibration dialog opens. Under Calibration Type choose Reflectance and save the new file.

What does surface reflectance tell us?

Surface reflectance (SR) improves comparison between multiple images over the same region by accounting for atmospheric effects such as aerosol scattering and thin clouds, which can help in the detection and characterization of Earth surface change.

What is the difference between top of the atmosphere TOA reflectance and surface reflectance?

Top-of-atmosphere reflectance (or TOA reflectance) is the reflectance measured by a space-based sensor flying higher than the earth’s atmosphere. These reflectance values will include contributions from clouds and atmospheric aerosols and gases. Surface Reflectance is the reflectance of the surface of the Earth.

How do you calculate reflectance value?

First compute Spectral radiance for kth band using formula: Radk = (DN*SRk)/1024. Here the SR denotes the Saturation Radiance. These value is for B2: 47.5614; B3: 45.6998; and B4: 31.5000. These values are in unit of (mW/(cm2-sr-um).

What is the significance of reflectance?

The reflectance of a material is the ability of the material to reflect the energy incident on its surface. The reflectance of a material is determined when light and solar radiation is incident on the surface of the material. This value can be used to describe the nature of a surface in terms of the surface finish.

Why is spectral reflectance important to remote sensing?

Spectral Reflectance Curve The reflectance characteristics of the surface features are represented using these curves. These curves give an insight into the spectral characteristics of different objects, hence used in the selection of a particular wavelength band for remote sensing data acquisition.

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