1. Objective
Land and underwater surveying works aim to accurately determine the topographic and bathymetric conditions of the project area, including all visible and submerged features, in order to provide a precise base for engineering design, construction, and asset management.
2. Land Surveying
2.1 Preparation and Planning
– Define scope of work: survey limits, purpose, deliverables.
– Establish coordinate reference system (WGS84 / UTM 38N).
– Set permanent benchmarks and control points.
– Select appropriate equipment: GNSS RTK, Total Station, UAV.
– Perform HSE risk assessment and field logistics planning.
2.2 Field Data Acquisition
– GNSS RTK and Total Station: measure surface features and boundaries.
– UAV Survey: perform LiDAR or photogrammetric flights; collect GCPs.
– As-built surveys: measure existing structures and utilities.
2.3 Data Processing and Modeling
– Upload all raw data and perform QC.
– Adjust network using control points and benchmarks.
– Generate point clouds, DTM, contours, and cross-sections using Civil 3D or GIS software.
2.4 Reporting and Deliverables
– Topographic map (DWG, DXF, PDF)
– Coordinate list (Excel/CSV)
– Contour maps, profiles, as-built drawings, and survey report
3. Underwater (Hydrographic) Surveying
3.1 Preparation and Planning
– Define waterbody and boundaries (river, lake, sea, etc.).
– Establish datum and tide reference.
– Prepare equipment: echo sounder, GNSS RTK, IMU, tide gauge, ROV.
– Conduct calibration and system integration tests.
3.2 Data Acquisition
– Single Beam Echo Sounder (SBE) for line-based depth profiles.
– Multi Beam Echo Sounder (MBE) for full 3D seabed mapping.
– GNSS and IMU integration for vessel positioning.
– Tide measurement and ROV inspection if required.
3.3 Data Processing
– Clean raw data and remove outliers.
– Apply tide and sound velocity corrections.
– Create bathymetric DTM and merge with land survey data.
3.4 Deliverables
– Bathymetric map (depth contours)
– 3D terrain model (XYZ grid)
– Cross sections and CAD/GIS files
– Survey report and calibration certificates
4. Integration of Land & Underwater Data
The integration process ensures a unified model of land and underwater surfaces for design and analysis.
– Transfer benchmarks and coordinate systems.
– Combine LiDAR and bathymetric data.
– Apply datum and geoid corrections.
– Produce a seamless Topo–Bathy DTM.
5. Standard Deliverables
– Combined Topographic + Bathymetric Map (DWG / GeoTIFF)
– 3D DTM / Mesh (XYZ / LAS)
– Contour Maps (0.5–1.0 m intervals)
– Cross Sections and Profiles
– Comprehensive Survey Report
6. Typical Equipment
Land: GNSS RTK, Total Station, UAV (LiDAR/Photogrammetry)
Underwater: Echo Sounder (Single/Multi Beam), GNSS RTK, ROV, Tide Gauge and GPR
Software: Hypack, QINSy, Civil 3D, ArcGIS, Global Mapper