Using an EDM (Total Station) for elevations only.
I discovered this trick when several of our transits and levels were damaged and stopped working.
No need to set up over a grid point. Simply set up the total station anywhere at the site. Make sure that it is level. Then shoot to a known elevation point. Add or subtract this difference in elevation to the total station’s instrument height. Sometimes it can make it easier to zero out the HI for the total station to know how much to add or subtract to the total station HI. Then reshoot to the known elevation point to confirm that the resulting elevation is the correct elevation of that known point. You can also shoot to other elevation points to confirm the elevation accuracy. This method is easy to use, and there are no calculations necessary to subtract the elevation from the HI of a transit or level from the stadia rod. The total station does all of this for you. This method also works great when there are dramatic elevation differences at the site.
Special Note: The total station also works great around camp for star gazing at night.