Use AIRSAR Scattering Classification to generate a classification image that discriminates between areas with no vegetation, areas with low and medium level vegetation cover, forested areas, and urban areas. ENVI also generates individual scattering mechanism images (odd bounce, double bounce, volume scattering).

The classification routine uses fully polarimetric AIRSAR data to determine the nature of radar scattering mechanisms for each pixel within the scene. ENVI pays particular attention to the presence and nature of vegetation. (This is an IDL implementation of routines similar to the MAPVEG program developed by Dr. Tony Freeman at JPL.)

All three (P, L, and C-band) Stokes matrix files are required as input for this classification.

  1. From the Toolbox, select Radar > AIRSAR > AIRSAR Scattering Classification. The Input Stokes Matrix Files dialog appears.
  2. Select the AIRSAR compressed Stokes matrix files to use for the classification.
  3. If the file has a valid AIRSAR header with all of the required parameters, the filename is listed in one of the Selected Files fields in the Input Stokes Matrix File dialog, depending on whether it is P-, L-, or C-band data. If you followed the suggested file naming convention described previously, correct filenames for the other two files are automatically entered into the appropriate fields. If not, you must repeat the file selection process for each band.

    If the file does not have a valid AIRSAR header, or if values are missing from the header, the AIRSAR Header Parameters dialog appears. Enter the missing values.

  4. Click OK. The AIRSAR Scatter Classification dialog appears.
  5. Enter the Kernel Size to use to determine the average values used in the scattering mechanism determination.
  6. Perform optional spatial subsetting.
  7. Select output to File or Memory for both the classification and the rule images (the scattering mechanism images).
  8. Click OK. ENVI adds the resulting output to the Layer Manager.