If there is a better way of doing something, we’ll find it.  The standard in the industry for calculating the amount of material needed to prepare a site, slope of a driveway, necessity of block, etc. is to use a transit.  In years past, transits were leveled with bubbles at 90 degrees from each other and peered through at a measuring stick.  Times changed to the use of laser transits which most heads level themselves and emit a plane of light to be read by a receiver that slides along the measuring stick.  Both methods require a line-of-sight from the head to the stick.  Economy Garages’ Sales Representatives use a high precision altimeter to measure elevations.  These altimeters do not need line-of-sight and can easily measure within 1/64” which is great for sites that have many trees, brush, or buildings in the way.