1. Load or generate a Raster data set into a Map window
  2. Find the Raster data set you want to customize in the Layers list and select it.
  3. Right click it and select Spatial data set

  4. A utility window showing the data, as a grid of values, will be displayed. 

Values of "-9999" represent no-data values. Right clicking the table shows a menu that allows for selecting and copying values.