Hydrographic Surveying Basics

Hydrographic Surveying

• Necessity: Essential for safe navigation, resource management (e.g., fishing, oil and gas exploration), marine construction, and environmental studies.
• Controls: Establish a reference framework using known points, such as geodetic control points, to accurately locate survey data.
• Shoreline Surveys: Determine the exact position of the coastline, using techniques like traversing and GPS.
• Gauges: Instruments used to measure water depth, flow rate, and tidal variations, providing essential data for navigation and hydrological analysis.
• Sounding Equipment: Devices like echo sounders, single-beam, multi-beam, and side-scan sonar, measure water depth and generate detailed bathymetric maps.
• Sounding Procedure: Involves carefully deploying sounding equipment, recording depths, and identifying features like shoals and underwater obstacles.
• Methods of Location of Sounding: Techniques like intersection, resection, and electronic positioning systems (e.g., GPS, DGPS, RTK) are employed to determine the precise location of each sounding.
• Three-Point Problem: A common method used for determining the position of a sounding using three known points on land, applying geometric principles.
• Analytical and Graphical Methods: These are used for solving and analyzing hydrographic survey data, transforming raw measurements into accurate maps and models.

Underground Surveying

• Surface Alignment: Establishing accurate horizontal and vertical alignment of shafts, tunnels, and underground structures using survey methods like traversing, leveling, and GPS.
• Correlation of Surface and Underground Surveys: Connecting surface and underground surveys through precise measurements, ensuring consistency and accuracy between the two.
• Weisbach Triangle: A method employed to transfer surface alignment underground by using three known points to establish the precise location of a point underground.
• Transferring Levels and Alignment Underground: Establishing accurate elevation and direction underground using techniques like plumbing, shaft surveying, and underground leveling.

Explore the fundamentals of hydrographic surveying, including the necessity for safe navigation and resource management. Learn about various controls, shoreline surveys, gauges, and sounding equipment used to measure water depths and create bathymetric maps.