Hewlett-Packard Model 3800 electronic distance measuring device. Approximately 2-mile range.

Monroe Rivers after a long hard day of observing.

Observer looking at control panel of Cubit Tape DM-60 electronic distance measuring instrument.

Leveling and centering retro-prism for reflecting light from electronic distance measuring instrument.

Lieutenant John Oswald preparing project sketch in Triangulation Party G-19 office trailer.

TMT - trailer-mounted tower - light and mirror tower. Leonard Bergman driving . Note telescoping tower ready to erect and extend to 100-feet above survey mark.

Control panel for TMT - trailer-mounted (light and/or mirror) tower.

Movable arm at top end of TMT used to center light and/or mirror over survey mark.

TMT being erected by Leonard Bergman. Donnie MacFarland standing to left.

TMOT - truck-mounted observing tower - with Leonard Bergman. Round instrument plate at end of 50-foot tower.

Preparing to erect TMOT.

TMOT going up with railing already in place.

TMOT in vertical position prior to extension.

TMOT at beginning of extension.

TMOT with instrument stand protruding during first stages of erection.

TMOT, Leonard Bergman constructing the outer tower to support the observer. TMT observering stand height was 50-feet.

Leonard Bergman during construction of TMOT outer tower. Note ladder leg to right. TMOT observering stand height was 50-feet above ground.

TMT on left, TMOT on right. These towers were set up during an open house at Cabool, Missouri.

TMT - this tower was set up during an open house at Cabool, Missouri.

Swedish Pole, telescoping pole to elevate light and/or mirror 70 to 90 feet over survey mark.

Closeup of moveable arm that mounts at top of Swedish Pole. This arm rotates and translates to enable centering of the light and/or mirror over the survey mark. Note small control boxes that control movement.

Swedish Pole being erected from stand on back of small truck.

Swedish Pole extended and supported by guy wires. Note one person could erect this device in approximately 1-hour and show a light 90-feet above a survey mark.

Swedish Pole with 10 prisms and strobe light above. The 10 prisms were used to reflect light from an electronic distance measuring instrument. The reflectors are 90-feet above the ground.

Lois Leigh, wife of party chief Lt. George Leigh, with a picnic supper at the base of a Swedish Pole in the Missouri Ozarks.

Four-foot wooden stand with pee-wee light on top. Note Sears Tower in background. National Geodetic Survey Triangulation Party G-19.

Display of various signal lights and other equipment for an open house. Wild T- 2 theodolite is set up on the right.

Earthquake movement as manifested by offset in center line of roadway.

A mirage on Cook Inlet.

Description not available.

Description not available.

Description not available.

Description not available.

John T. Smith, Jr., Chief of the Photogrammetric Operations Branch.

Description not available.

James Lindly observing and Leo Gittings recording leveling observations.

Leo Gittings recording leveling observations.

Ross Mackay observing astronomic latitude and longitude with Wild T-4 Theodolite. Richard Cohen, Chief of Party.

Richard Cohen recording astronomic observations with Wild T-4 Theodolite.

Thirty-seven foot tower on hill-top in Connecticut.

Lois and Eric Leigh tending light at Bald Hill, Connecticut. Wife and father of party chief, Lieutenant George Leigh.

Description not available.

Leveling operations. Davey Crockett is on the gun while Anita Whitis is recording.

Testing of special motorized leveling project. Anita Whitis was the instrument operator.

Anita Whitis running the "gun" on the North Portico of the White House during leveling operations.

Anita Whitis being filmed by news crew while conducting leveling operations on the North Portico of the White House.

Anita Whitis running the "gun" on a low shot. By Anita's admission, "OOPS! Never, ever set an instrument up for a shot like this." The level is a self-leveling Ni-1 instrument.

Anita Whitis with two rodmen and recorder during White House leveling operations .

Anita Whitis testing the prototype motorized leveling unit at Corbin, Virginia, in December 1978.

Chief of leveling party, Dan Frazier, working in the office.