If you're using terrain features, checkpoints you want should be described as:

The most effective checkpoints when using terrain features for navigation are those described as unique in shape. Unique shapes stand out against their surroundings and are easier to identify, especially in low visibility conditions. They provide distinct visual cues that help with orientation and can be pivotal in maintaining situational awareness. These features can be natural formations, like unusual rock formations or specific tree arrangements, or man-made structures that are easily recognizable from a distance.

While large features can also be helpful, the focus on unique shapes emphasizes the importance of distinctiveness. Commonly shaped features or simple structures may blend into the landscape or become indistinguishable from one another. Therefore, relying on unique shapes as checkpoints enhances navigation reliability in complex terrains, making them critical for effective route-planning and land navigation skills.