Masking unwanted areas

When an image is corrected for radiometric and geometric distortions, areas that are not of interest for the mapping purpose can be masked out. Such areas are: water, clouds, shadows.

This can be done by:

  • Using existing map or GIS files of the feature to be masked
  • Using band ratios to extract the shaded areas
  • Using NIR band to extract water as it does not penetrate water
  • Delineating areas to be extracted
Land and deep-water masking
Geometric corrected image
Masking: Image of land without water and clouds.