Running the TOA Reflectance workflow

• In the Output data type list, select an appropriate choice from the following:
  • 16-bit signed: Computes the output reflectance values scaled, by default, from 0 to 10,000 stored in a 16S channel. The user can use Scale factor and Scale offset to set different values for the output.
  • 16-bit unsigned: Computes the output reflectance values scaled, by default, from 0 to 10,000 stored in a 16U channel. The user can use Scale factor and Scale offset to set different values for the output.
  • 8-bit unsigned: Computes the output reflectance values and stores them in an 8U channel. The user must set Scale factor and Scale offset to set the range of values for the output.
  • 32-bit real: Computes the output reflectance values scaled, by default, from 0 to 1.0 stored in a 32R channel. The user can use Scale factor and Scale offset to set different values for the output.
  Note: With 32-bit real output, reflectance values greater than one (1) are possible over very bright areas in which specular reflectance is occurring; that is, all light is reflected in one direction. Such situations occur typically over roofs of buildings (mirror reflection), water (sun glint), and, to a lesser extent, over snow and very thick clouds.
• To generate an additional spectral classification layer during TOA atmospheric correction, select the Compute spectral classification check box.

A progress monitor appears, indicating the running processes. When the operation is complete, a new TOA_Corrected layer appears in the Focus Tree List.

The information set in the Sensor and image settings is shared with all other Atmospheric Correction workflows, allowing you to reuse the same information to perform other tasks without having to re-specify the settings. Note, however, that all workflows apply to the same data set; specifying a new input data set in another workflow will overwrite the existing information.