Coast and Geodetic Survey Tide Predicting Machine No. 2. Forward driving shaft, Rear component section.

Roberts or India Office Tide Predicting Machine.

Dial case of Coast and Geodetic Survey Tide Predicting Machine No. 2.

Ferrel Tide prediction machine. Tide Predicting Machine No. 1 of the Coast and Geodetic Survey.

Main driving gears and automatic stopping devices of Coast and Geodetic Survey Tide Predictng Machine No. 2.

Coast and Geodetic Survey Tide Prediction Machine No. 2. Front component section - vertical driving shaft.

Coast and Geodetic Survey Tide Prediction Machine No. 2. Dial case and height side.

A Kelvin Tide Predicting Machine ca. 1926. This particular model was used by Japan, Portugal, and the Tidal Institute of Glasgow.

Back end of Coast and Geodetic Survey Tide Prediction Machine No. 2.

A heliotroper at Mount Margaret triangulation station just north of Spirit Lake.

Illustrating conducting surveys of the oyster grounds of Maryland.

Illustrating conducting surveys of the oyster grounds of Maryland.

Maryland State Shellfish surveys from the INVESTIGATOR.

Tide station transmitter for communicating with satellite

Tide station transmitter for communicating with satellite

Tide station transmitter for communicating with satellite

Tide station transmitter for communicating with satellite

Tide station transmitter for communicating with satellite

Monitoring tide installation

3-D view of portion of Portland Harbor showing soundings overlayed over colored depth ranges.

Unidentified 3-D view of bottom which includes rock outcrops and sandwaves

Sidescan sonar imagery overlaying 3-D view of bottom generated by multi-beam sonar. Grey-scale 3-D image enhances feeling of looking at aerial photograph of rock outcrops.

Colored 3-D image of Bowie Seamount in the Gulf of Alaska with overlayed depths.

Grey-scale 3-D image of Bowie Seamount derived from multi-beam sounding data.

Graphic illustrating the density of sounding data obtained with leadline sounding technology.

Graphic illustrating the density of sounding data obtained with single-beam acoustic sounding technology.

Graphic illustrating the density of sounding data obtained with multi-beam acoustic sounding technology obtaining 100% bottom coverage.

Graphic illustrating bottom coverage obtained with both multi-beam sounding data and sidescan sonar data. These datasets can be combined in many ways to derive much information concerning the nature of the seafloor.

3-D image of Diamond Shoal showing combined multi-beam sounding/sidescan sonar data product. This graphic shows the distinct difference in bottom types of shoal points versus the deeper regional bottom.

Bottom-mounted multi-beam sonar transducer. Mounted in the hull of a NOAA survey launch.

Towed sidescan sonar fish with depressor kite for helping maintain elevation off bottom.

Bottom mounted sidescan sonar system.

NOAA Launch Whiting-2 showing bottom-mounted sidescan sonar system.

NOAA Launch Whiting-2 showing bottom-mounted sidescan sonar system.

Hydrographic data processing office of NOAA survey ship.

Lt. Albert Theberge operating Wild T-2 theodolite on north shore of St. Thomas, U.S. Virgin Islands.

December 1944 tide and light diagram for Davao Gulf, Philippine Islands. The Coast and Geodetic Survey produced such diagrams for many military operating areas during World War II.

September 1944 tide and light diagram for Manila Bay, Philippine Islands. The Coast and Geodetic Survey produced such diagrams for many military operating areas during World War II.

Predicted tide curve for Cebu, Philippine Islands, for November 1944. This tide prediction curve was produced on Coast and Geodetic Survey Tide Prediction Machine No. 2.

Part of the crew of the "Monitor" from a photograph taken soon after the fight.

Sumner's Corps crossing the overflowed "Grapevine Bridge" to reinforce Couch at the Battle of Fair Oaks. Coast Surveyors Dorr and Donn helped find crossings of White Oak Swamp during the Seven Days.

Mortar-steamers attacking the water-battery of Fort Jackson during the Battle of New Orleans.

Map showing the defenses of the Mississippi and the positions of the mortar- fleet at the opening of the bombardment. The Coast Survey carried triangulation up the Mississippi River which allowed positioning the mortar vessels for indirect artillery fire, one of the first instances of geodesy and survey being used to position artillery (it was done under David Dixon Porter of the Navy)

Mortar-schooners engaged against Fort Jackson. Distance of lead schooner from the fort, 2,850 yards as determined by Coast Survey. Total number of shells fired in six days was 16,800. One of the first instances of the use of geodesy for indirect artillery fire.

Bird's-eye view of the passage of the forts below New Orleans.

David Dixon Porter receiving Confederate officers on his flag-ship the Harriet Lane.

The U.S.S. MISSISSIPPI attempting to run down the Confederate ram "Manassas" during the passing of the forts on the Mississippi River.

Confederate sharp-shooters attacking the mortar-boats during the Battle of New Orleans.

Early balloon warfare. Professor T. S. C. Lowe observing the Battle of Seven Pines from his balloon "Intrepid" on the north side of the Chickahominy River during the Peninsula Campaign.

Building a corduroy road across White Oak Swamp. Coast Surveyors Frederic Dorr and J. W. Donn guided part of the Union Army across this swamp during the Seven Days.