Coming soon · Geometry
Underwater Survey and 3D Mapping
Geometric capture of structures and water bodies. Depth profiles, site plans and reference models in CAD-/GIS-compatible formats — directly usable by engineering offices.
Problem & Triggers
As-built records of older structures frequently no longer match reality. Restoration planning, construction progress documentation, area accounting or expert reports need current geometry data — in a format the engineering office can process directly.
ScanSustain is engaged when restoration is being prepared, an as-built survey is due before a change of operator, construction progress must be documented, or environmental impact assessments require geometric baselines.
Method & Technology
Depending on the task, acquisition combines photogrammetric video capture and multibeam sonar. Data is georeferenced, rectified and processed into point clouds, depth profiles or 3D models.
Results are delivered in common exchange formats (DXF, LAS, orthomosaic, GeoTIFF and more), so the engineering office can continue working without media breaks. On request we also produce scaled plans or as-built books.
The choice between photogrammetry and multibeam sonar depends on visibility, water depth and the required level of detail. In good visibility, photogrammetric capture delivers photorealistic, high-resolution point clouds with true-to-life texture — suitable for structural inspection and detailed documentation. In limited visibility, larger areas or deeper water, multibeam sonar takes over the capture, largely independent of turbidity and light conditions, though with lower texture resolution.
In practice, both methods are frequently combined: multibeam sonar provides the large-area bathymetric baseline, while photogrammetry adds targeted detail capture at critical structural sections. This combined approach is established for underwater surveys of harbour basins, dams and quay walls, where both overall geometry and local anomalies must be documented.
Water Conditions & Operating Limits
Underwater visibility is the primary factor determining which method is used. Clear waters with several metres of visibility allow full photogrammetric capture; turbid waters, flowing rivers with current, or deeper lake areas require sonar-based methods. Operating depth depends on the ROV system deployed and is defined in the initial consultation based on the specific task.
Season and water level further influence planning: after flood events or with strongly fluctuating water levels, a current survey may deviate from older as-built records — an additional reason to verify existing data before planning or expert assessment.
Typical Applications
Underwater survey is used across a wide range of project phases — from initial as-built documentation to ongoing monitoring of existing structures. The following overview shows typical situations where precise underwater geometry makes the difference:
- Restoration and deconstruction planning of harbour facilities
- 3D model of quay walls, bridge piers or dam walls
- Bathymetric mapping of harbour basins and rivers
- Construction progress documentation for underwater works
- As-built surveys for owner or operator change
- Geometric baseline for monitoring programmes
Mission Workflow
- Briefing
Target accuracy, delivery scale, exchange format and constraints are defined. - Planning
Reference and control points are set, acquisition plan and equipment configuration prepared. - Acquisition
Field capture with sonar, ROV photogrammetry or combined methods. Depending on visibility and task, the method is adapted on-site as needed. - Processing
Rectification, georeferencing, point cloud creation, modelling and quality control. Anomalies are flagged and listed separately in the handover report. - Handover
Delivery in agreed formats including accuracy record and method protocol.
What You Receive
Point cloud / 3D model
Exported as LAS, PLY or DXF with documented accuracy and coordinate system.
Depth & site plans
Georeferenced maps at the agreed scale, GIS- and CAD-compatible.
Accuracy record
Record of control points, methodology and achieved tolerances.
Documentation & Traceability
Every underwater survey is handed over with a complete method protocol: the methods used, control points applied, accuracy achieved and time of capture are documented. This traceability is a prerequisite for use in expert reports, tender documents or before authorities.
Raw data is archived for traceability and possible reprocessing. For recurring surveys of the same structure or water section, the documented methodology enables a robust comparison between capture dates — the foundation for monitoring programmes and condition tracking over time.
Benefits for the Client
- Directly processable data without media breaks
- Solid geometry for tender, planning and settlement
- Traceable accuracy for expert reports and authority submissions
- Baseline for comparison with follow-up surveys (monitoring)
- Reduced queries through defined exchange formats
Relevant Sectors
Survey & Mapping is particularly in demand in these sectors:
Adjacent Services
If only a condition assessment without geometric evaluation is required, ROV Inspection is sufficient. If the goal is detection and localisation rather than geometry, Sonar & Scanning is the right path. If a geometric baseline is to be re-captured over time, survey interlocks with Monitoring & Recurring Inspection.
Frequently Asked Questions
What accuracy can be achieved?
Depends on method, water conditions and control points. Centimetre to decimetre accuracy in CAD-ready products is realistic — the specific target is set in the briefing.
In which format is delivery?
Standard formats on request: DXF, LAS, PLY, GeoTIFF, DWG, PDF plan. Further formats by agreement.
Is the result prepared for court use?
Yes. Accuracy record, method protocol and control points are part of the handover, making the result traceable and verifiable.
Can the survey be repeated later?
Yes. Methodology is logged so follow-up surveys can use the same reference frame. This is the prerequisite for delta comparisons.
Up to what water depth is underwater survey possible?
Maximum operating depth depends on the ROV system deployed and the on-site visibility conditions. The specific depth limit for your project is defined in the briefing based on the task at hand.
How does underwater survey differ from classical land surveying?
Land surveying works with direct optical sight and terrestrial instruments. Underwater survey must compensate for turbidity, light refraction and limited visibility — through photogrammetric and acoustic methods that deliver robust geometry data even in reduced visibility.
Related pages
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