Hello Everyone, It hasn't been too many years ago that surveyors  face and had to over come the task of crossing a wide river or even a wide canyon with only there levels.In doing this they work out the science of Targeting procedures  and Reciprocal Leveling with corrections for curvatures and refraction amounts for a half a mile to over a mile. Rivers at even a 1000 ft were a challenge. Think of how the first surveyors felt when they look across the Mississippi. From working on it i know how different the grade can change on its water surface from one side to the next. Many things govern the laws of how this water flows down stream and what the incline rate of its surface remains at. Crossing a large canyon you have no water. So  look at these stories of how these surveyors work out these problems and lets hear yours

Billy.