Following the Spanish-American War, the Philippine Islands became United States Territory. Consequently, the Coast and Geodetic Survey followed the American flag and commenced providing this vast archipelago with modern nautical charts. An assignment in the Philippines was the great defining experience of a lifetime for many young officers. Nothing in their American background prepared them for the kaleidoscopic melange of cultures, terrain, flora, and fauna that was the Philippine Islands. Over 7,000 islands were spread over an area equal to half that of the United States. The northern islands were overlain with Spanish culture while the Southern islands were predominantly Muslim. Besides these major cultural units, there were numerous tribes and over 100 dialects with which to contend.
The Coast and Geodetic Survey ships based in Manila but sailed out to all of the outlying islands. Cebu, Zamboanga, Puerto Princesa, and even Sandakan in Borneo knew the Coast and Geodetic Survey ships. They sailed over and charted the azure seas of the Philippines - the Sibuyan, the Visayan, the Bohol, the Celebes, and the Sulu. The small ships braved the typhoons that regularly visit this corner of the world, sometimes with near disastrous results. The shore parties put up with: frequent earthquakes; the occasional volcanic eruption; mangrove swamps; razor-sharp coral rocks; head-high sawgrass; surf that up-ended launches and skiffs; and an endless succession of high mountains covered with dense jungle on all of the larger islands. The common feature of the local fauna was that most species wanted to jump on, bite, eat, poison, or in some other way harm the surveyors that came into their environment. Poison cone shells, sea snakes, and various venomous fish frequented the reefs; king cobras approaching 18 feet in length lived on the southern islands; pythons approaching 30 feet in length inhabited the jungles; and huge saltwater crocodiles posed a constant threat to the surveyors while they worked in the southern islands. Malaria, typhoid fever, dysentery, and other tropical diseases were constant companions of the surveyors. And occasionally a hostile populace would attempt mayhem on unsuspecting surveyors.
Through all of this the Coast and Geodetic Survey labored for the forty years prior to the Second World War. Fortunately for American armed forces, the Survey had virtually finished surveying the islands prior to the outbreak of hostilities. As such, Coast and Geodetic Survey charts, tide predictions, and tidal current predictions were an intrinsic part of American planning and tactical operations in the retaking of the Philippines. To the credit of the American surveyors, they trained local engineers in their techniques and methods. Just prior to the war there were numerous native officers being trained to take over the functions of the Survey. Following the war and the advent of Philippine independence, there was a trained cadre of officers and technicians able to smoothly step in and take over the operations of the Survey.