What is SnakeGrid?
SnakeGrid is a way of creating low distortion coordinate systems that simplifies the survey, design and construction process.
Moving between the curved surface of the earth and a flat plane design environment has always presented problems to engineering projects.
SnakeGrid is purely about creating a map than matches reality.
You may think that was whole point of a map, that it is meant to represent reality, and that is true, but it is how well they match reality that matters. Traditional map projections, contain distortion in things like distances, angles or areas. All maps preserve one aspect at the expense of another with the choices depending upon the purpose of the map. The problem is the curvature of the earth, you simple can’t flatten a curved surface, the earth, onto a flat sheet of paper, a map, without stretching, skewing or tearing it.
National grids and the UTM series of projections are great for wide area mapping, but their inherent distortion is significant, they were not designed for engineering accuracy. The use of them for engineering projects increases complexity and risk as you cannot construct what has been designed. It can be the same size but in a different place, or in the same place but it will be a different size.
A project’s coordinate system is the backbone of the project; and just like any other mapping system it should be designed for its intended use ensuring it is fit for purpose.
The main benefit from a survey point of view for us is the ability to work without scale factor along some very long survey routes.
It is also extremely easy to convert co-ordinates between ETRS89, SnakeGrid and OS which comes in handy, especially when we are dealing with designers, GI professionals and GIS professionals who often don’t understand the concept of scale factor.
Graham McInally
Project Surveyor, AECOM
Our approach
Various approaches have been used, most involve a trade-off between the level of distortion and the amount of coverage they provide increasing complexity and risk; others, although simpler to implement, require the project to meet very specific criteria and thus are not always suitable.
SnakeGrid doesn’t accept the compromise between distortion and coverage. By exploiting the characteristics of the project SnakeGrid provides a low distortion solution that is continuous across the entire project whilst retaining its relationship to the rest of the world, exactly the requirements of coordinate systems for modern engineering projects.There are many advantages to this approach – no need to switch from one coordinate system to another; no need to make scale factor corrections. A single coordinate system for all data sets, allowing easier updating and re-use of survey data; a one-to-one relationship between the design and the ground.
A single file defining the projection compatible with all major kit manufactures allowing the seamless transfer of information from collection to design and onwards to the construction phase through GNSS setting out and GNSS controlled machinery/plant. All parties working seamlessly together all the time.
How do you access SnakeGrid? It’s as simple as using any other coordinate system.
Why use SnakeGrid?
Trusted by network operators, design consultancies and construction firms, discover why SnakeGrid is chosen for some of the largest engineering projects in the world.
Single continuous coordinate system
SnakeGrid creates a single coordinate space that can extend for hundreds of km’s even. Routes that diverge significantly can also be accommodate whilst still be covered by a single parameter file, maintaining the low distortion continuous philosophy of the SnakeGrid approach.
Near zero distortion
The level of distortion is below survey accuracy so in practice it can be considered distortion free. With the design space matching the real world the geometric properties of shapes and alignments are retained during the construction phase. Assets are built exactly as they were designed.
Seamless link between phases
A single recognised coordinate system for the lifetime of the asset improves data management and simplifies workflows. Integration with field equipment & software allows data to flow freely between survey, design and construction improving efficiency and creating confidence. External data sources can also be easily accessed.
Reduced risk across the project
With all data being based on the projects coordinate system, the single, low distortion approach of SnakeGrid provides a solid foundation for project reducing many of the risk factors faced by projects. Teams are free to concentrate on the task at hand, delivering better outcomes whilst saving time & money.
SnakeGrid has, to all intents, eliminated grid issues on HS2. We just don’t have issues.
More complex cases
Quite often we are asked if we can cover diverging routes on same grid, or if we can extend the original grid as the projects move into addition phases.
The answer to both these questions is yes, and to the end user it will appear as one single coordinate system maintaining the low distortion and continuous philosophy that underlies /guides the SnakeGrid approach.
By utilising this approach entire national network have been covered (NI rail) with a limited number of SnakeGrids all accessed via one set of parameters.
All the benefits of a traditional coordinate system with the accuracy of an engineering grid.
Talk to an expert
Discover how SnakeGrid could transform your next survey project.
Request a quote or more information today.
