41. Triangulation and navigation bases were established along with tide gauges and then topographic and hydrographic surveys were begun. 42. The hydrographic survey ship Townsville for submerged debris, allowing the port to reopen three days after the cyclone. 43. A massive amount of data is collected during the typical hydrographic survey , often several soundings per square foot. 44. HMS " Hecate " was carrying out a hydrographic survey in collaboration with the government of the Republic. 45. The remaining four weeks involve the acquisition of various methods of conducting hydrographic surveys and creating a hydrographic chart. 46. The vessel was loaned to the Department of Mines and Technical Surveys for use as a hydrographic survey platform. 47. In 1963 the British Royal Navy Hydrographic Survey Unit found there were two islands, not one as previously supposed. 48. Charted during an ANARE ( Australian National Antarctic Research Expeditions ) ( Thala Dan ) hydrographic survey in 1961. 49. In 1895 it was reclassified as Aviso and remained in Patagonia on hydrographic survey tasks, based at Ushuaia. 50. The first naval hydrographic office was created in 1905 and its first mission was the hydrographic survey of Maliakos Gulf.
