Robot swarm, Maximum area coverage
I assume by "comparable part of the area" you mean that they should all scan a region of equal area. Additionally, knowing what kind of plane area you have would be helpful, is it convex, is it concave, is it just a regular polygon? If you know this then there are easier ways to do it.
So assuming you want for the worst case, a concave polygon, the best solution that I know of is this.
This page has a detailed explanation of the algorithm and there's even some comments with implementations.