# Uniform and non-uniform cost maps [closed]

I can not find a clear answer on the internet about the difference between a uniform and non-uniform cost map. I am interested in getting an answer in the context of grid maps for robot navigation.

EDIT: I found the answer, in my case the uniformity was referring to the cost of traversing from one cell to another. Thus, if the cost is fixed the cost map is said to be of uniform cost. Otherwise, if the cost is variable the map is said to be of non-uniform cost.

## 1 Answer

The cost map is indeed an important sub problem within robot navigation, because it guides a solver into a certain direction. The idea is, that a sampling based solver like RRT is searching in the cost map for a gradient descent which reduces the state space to interesting regions. A fast path planner and a well created cost map are the same.

Uniform cost maps for path planning are the easier one. The distance to the goal is determined by the distance in the euclidean space which is sqrt(diffx²+diffy²) and all the coordinates on the map can be traversed. Non uniform cost maps are more realistic because each position is labeled with a probability value for the existence of an obstacle.