Before revision: (Refer to the figure on the other side) Thus, For gentle slopes, For steep slopes, For very steep slopes , , Or, more simply, or Where: is the correction of measured slope distance due to slope; is the angle between the measured slope line and horizontal line; s is the measured slope distance.
After revision: (actually exact expressions for any slope)(Refer to the figure on the other side) Thus, For gentle slopes, For steep slopes, For very steep slopes , , Or, more simply, or Where: is the correction of measured slope distance due to slope; is the angle between the measured slope line and horizontal line; s is the measured slope distance.