Finding steepest paths

As the name implies, this technique is used to find the steepest path down a slope. Besides its use for modeling the route a fluid will take down a slope (water flow, mud flow, lava flow, etc.), it can also be used to estimate the accuracy of a surface. For example, you can create a steepest path from the origin of an existing stream then compare it to the actual path of the stream. Assuming the original stream data is accurate, you can estimate the accuracy of your surface model based on the deviation between the two paths.

By comparing the steepest paths (yellow lines) with the actual stream locations (blue lines) you can estimate the accuracy of this surface model.