Hydrographic and Dredging

New ways to present hydrographic data have been introduced to satisfy those wishing to work to Admiralty or Engineering survey standards. Equally suited to intertidal, nearshore or deep sea operations, LSS allows the user to present the terrain surface and annotate to the internationally recognised hydrographic standards. As point elevation labels are displayed 'on the fly' it is possible to switch between labelling nomenclature at any stage and plot or export knowing that the settings have been implemented and will be transferred accurately to AutoCAD™. In those surveys where some points are above and others below the chart datum, LSS automatically displays hydrographic and land elevations and contours in the correct manner without the need for any user intervention.

For the benefit of those involved in design and dredging, LSS contains many powerful 3D terrain design functions, specifically for trench and sea wall design, pipeline and reclamation projects.

The highlights include:-

    In use by dredging and hydrographic survey companies
    Displays, plots and exports models with the correct Admiralty or Engineering level and contour display details
    Used for volume calculations and trench and sea wall designs
    Compare models and display level changes
    Automatically handles a mixture of land and hydrographic survey data
    Change label display 'on the fly' and at any stage without affecting the base survey data
    Fly-bys and colour banded 3D views

Recommended product for this work: LSS Elite

Case Study - Van Oord Dredging & Marine

Imagine an object the size of a football pitch, but 200km high, well that's the amount of material measured by HAM, dredging and marine contractors using the LSS terrain modelling software from McCarthy Taylor. Van Oord (originally Ham Dredging & Marine) have used LSS on over 60 large scale projects since 1996 and have crossed the magical 1 billion cubic metres mark.

 

The fast modelling capabilities of LSS are much in demand, especially when dealing with large data sets. Coupled with unique design and analysis options, LSS provides the complete solution for many involved with measuring or altering the earth's surface.

The company was involved in a joint venture on the world's largest land reclamation project which involved the dredging and pumping of approximately 200 million cubic metres of sand to reclaim 1000 hectares of new land at Jurong in Singapore. LSS was key in helping Van Oord win the tender for the contract through its ability to determine volumes quickly and accurately, and its power as a comprehensive design tool.

LSS is used primarily at the tender stage by Van Oord for a wide range of projects, including New harbour developments, Land reclamation, Existing harbour extensions, Breakwaters, Maintenance, Beach nourishment, Borrow area management, Subsea pipeline trenches, Subsea pipeline protection fills and Outfall and other trenches.

 

Coastal Monitoring

LSS has been used for beach and coastal surveys since the very early days of the software. At that time 'two-man' teams would use EDM survey equipment to measure a beach. More recently however, with the threat of coastal erosion due to rising sea levels and the increased risk from damaging storms many organisations are now required to monitor stretches of coastline and beaches much more frequently.

One solution to providing quick and accurate beach surveys has been the use of a GPS antenna mounted on a 4 wheel drive All Terrain Vehicle (ATV). This setup allows hundreds if not thousands of surveyed points to be collected in a day.


 

The Problem

In spite of the obvious advantages of this method, there is one major disadvantage. When the ATV is driving along a sloping beach the pole of the antenna is not vertical which means that the surveyed points are not where they should be. The diagram below illustrates the problem.

While, for gently sloping beaches the error will be minimal, when traversing beach berms and storm ridges the errors can be quite large. The table below gives you some idea of the likely errors.


The above table assumes a 1.4m pole height, 1.2m wheelbase length and 1.0m wheelbase width.
The Solution

What we have done in LSS is provided a solution to this problem and it is called 'GPS Pole Verticality Correction'. This command will make the necessary adjustments to every point which was surveyed from the ATV and generate a corrected terrain model. This command is available in LSS Solo, although the minimum that would be required in order to calculate volumes (often a requirement of beach surveys) would be LSS Vista.

While this survey method may have been superceded by UAV, LiDAR and Laser Scanning methods in recent years, this article serves to illustrate our commitment to providing innovative solutions to a wide range of problems.

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