Leveling down the trail into Glen Canyon, Arizona, in 1921. Traditional surveying methods require an unobstructed line-of-sight between survey observation points.
With the NOAA 200th Celebration coming to a close at the end of 2007, maintenance of this Web site ceased. Updates to the site are no longer being made.
Leveling down the trail into Glen Canyon, Arizona, in 1921. Traditional surveying methods require an unobstructed line-of-sight between survey observation points.