Scouting radius is the hero's line of sight. In other words, the distance a hero can see in unscouted areas. The basic scouting radius is five, but it can be increased with Scouting secondary skill or with scouting artifacts Spyglass and Speculum. Basic scouting radius for heroes is five, but with scouting, spyglass and speculum, it can be increased up to 10. In HotA scouting radius can be increased up to 12 for heroes without scouting specialty. With scouting specialty of Miriam or Beatrice maximal radius can go up to 24.