Hydrographic surveys are specialized marine surveys that map and measure underwater features of bodies of water, like oceans, rivers, and lakes. These surveys employ sonar and GPS technology to chart water depths, seabed topography, and submerged objects. Hydrographic surveys are crucial for navigation, maritime safety, and various marine-related activities like port development, environmental assessment, and resource management. They ensure accurate information for safe and efficient navigation and sustainable use of water bodies.