Longitude and latitude lines are drawn on the Coast and Geodetic Survey projection ruling machine. This machine eliminated thousands of man-hours of drafting time that would have been required to produce the projections made for the thousands of maps produced for the Allied Armed Services during WWII. Barbara Clayton and Patricia Hayes are the operators of the machine.

The vacuum printing frame used to process wet plate negatives to aluminum printing plates.

Information from other sources is reduced and included in the compilation drawing. An operator is using a pantograph to produce the reduced image.

Operating the 50-inch camera which was invented by Lieutenant Otis Reading during the 1930's. This camera could photograph images up to 50 inches square. It would reproduce images with an error of less than one thousandth of an inch.

The negatives are then exposed to sensitized aluminum plates.

The sheets are then reduced to the scale of the chart, proper selection of the material which will appear on it being made, and the whole worked into a compilation drawing.

The soundings showing depths throughout the water areas are machine-cut through the film of the negative.

After the plate is completed, a proof is made on the above press. The plates are made for offset printing and the proof is made by taking the print from the plate to a rubber blanket fastened on the cylinder. The rubber blanket deposits the print to the paper. Up-to-the minute corrections are applied to the plate at this stage, and the plate is then ready for final printing.

Engraving on a nautical chart negatives.

Engraving on nautical chart negative.

Compiling a nautical chart from field survey sheets and other data.

Preparing printing plates for presses.

Compilation work for a nautical chart.

Reproduction methods of the United States Coast and Geodetic Survey.

Negative engraving tools.

All the field data are sent to the Washington Office where the triangulation, magnetic, and tidal work is examined by mathematicians who make the necessary adjustments to connect it with work already done. Cartographers complete the plotting, inking and verification of the hydrographic and topographic sheets.

Using a multi-plex stereoplotter to develop shoreline and topography from aerial photography.

Army aerial photography unit with three-lens camera. Circa 1920's.

Nine-lens camera used by the Coast and Geodetic Survey. It obtains topography to be employed on nautical charts, and for making airport surveys. The camera takes nine photographs simultaneously of adjoining areas on a single piece of film 23 inches square. The center photograph is taken vertically downward, while the other eight are oblique views.

Nine-lens photograph. Reduction of a nine-lens camera photograph as taken with the aerial camera of the C&GS. The top photo represents the contact print from the negative, and the bottom photo represents the transposed view.

Monument 272 along the Alaska-Canada Boundary in the Southeast Alaska area.

Third-order triangulation station Iquak in southwest Alaska, while attached to the USC&GS Steamer DISCOVERER in 1923.

Surveying party climbing over a glacier with Mount St. Elias in the background. Note dog with pack in foreground.

Packing across a river in South Mindanao, Philippine Islands, enroute to a triangulation station.

A triangulation party at the foot of Mt. Galintan in the Davao Gulf region of Mindanao, Philippine Islands. The party but a few minutes before had emerged from the woods in the background through which they had traveled by compass alone for a day and a half. The vegetation is cogon grass of moderated height. However, even here it reaches to the men's waists.

Freighting in Texas with a barrel wagon.

Packing a theodolite across the swollen Verde River, 1924.

Canadian and U.S. representatives of the Alaska-Canada International Boundary Survey meet at Point Demarcation on the Beaufort Sea. The U.S. representative took great pride in having attended Princeton University.

Northernmost point on the Alaska-Canada Boundary, where the 141st Meridian projects into the Beaufort Sea. The U.S. Coast and Geodetic Survey represented the U.S. in the delineation of this boundary.

The "goat trail" in Chitistone Valley used during the Alaska-Canada Boundary Survey, 1913.

Early C&GS trucks passing through plowed field.

A plane-table party working in Alaska. The use of aluminum-mounted topographic survey sheets greatly facilitated plane table surveys in regions where fog and rain prevail, as they eliminate the difficulty due to distortion of ordinary paper sheets.

The making of a plane-table survey in Philippine mangrove swamps. These waters were frequented by salt-water crocodiles necessitating a constant lookout . This party was off the C&GS Steamer FATHOMER during the field season of 1915-1916.

Shoreline topography in Alaska.

Topographic work in Alaska, Glacier Bay area, off of C&GS Ship WESTDAHL.

Topographic work in Alaska, Glacier Bay area, off of C&GS Ship WESTDAHL.

A theodolite for observing horizontal angles.

Observing horizontal angles with a Wild T-3 theodolite from a lighthouse.

Triangulation tower constructed from pre-cut lumber at Tacoma North Base. Pre- Bilby Tower era.

Building crew constructing a steel portable Bilby triangulation tower.

Station Tensas. A 159-foot Bilby tower was constructed here in April, 1931. Lieutenant Ralph Pfau was chief of party at this station along the Atlanta- Shreveport triangulation arc.

Using collimator to align instrument observing stand at top of Bilby tower with mark in the ground at a triangulation station.

A Bilby triangulation tower in the vicinity of an oil production facility.

Light keeper orienting lights for triangulation observing party prior to beginning night's observations. Apparently operating off a water tower.

Making near contact on low bench over a traverse station. Invar tapes pulled to maintain a constant tension were used to measure distances in the days before electronic distance measuring devices.

Contact platforms were under water because of heavy rains during traverse survey using invar tapes. Along the Florida West Coast in 1928.

Coast and Geodetic Surveyors using early geodimeter for measuring distance by laser light over long distances.

Coast and Geodetic Surveyors using early geodimeter for measuring distance by laser light over long distances.

Mechanized leveling before the automobile. Using a railroad velocipede to transport a level instrument as well as serve as the stand.

Second-order leveling observing unit working in Virginia in 1935.