About SnakeGrid
Discover the story behind SnakeGrid, from its academic origins at UCL to its role today supporting accurate, low-distortion coordinate systems for major infrastructure projects worldwide.
The story so far
On a relatively small site, treating the ground as flat introduces almost no error, and a standard coordinate grid does its job. Stretch that over a railway running from London to Glasgow, however, and things get a little more complicated. The route covers enough of the earth’s curved surface that a standard map projection has to compromise: keep the grid continuous the whole way, or keep scale distortion small, but not both. For railway tracks (roads, tunnels or pipelines) set out to tight tolerances across that distance, neither is much use.
Origins and academic development
SnakeGrid came out of University College London, where Dr Jonathan Iliffe, a geodesist in the Department of Civil, Environmental and Geomatic Engineering, took on a problem Network Rail had set: give a long route one grid with a scale factor close to one from end to end. His method was to ‘unpeel’ the earth along the line of the route, following it in plan and in height, which keeps scale distortion inside a few parts per million the whole way. It began as RailGrid, built on the Snake Projection, and had its first outing on the West Coast Main Line.
It was published research before it was a commercial product. Iliffe set the method out with Network Rail’s Chris Preston in a 2007 Survey Review paper, and UCL Business, the university’s commercial arm, refined the algorithms across several versions after that. For surveyors deciding whether to rely on it, that pedigree provided significant reassurance.
Our timeline
From its first commercial outing to becoming the go-to coordinate grid for engineering projects throughout the world, for almost 25 years SnakeGrid has redefined how long, linear survey projects are delivered.
1990s – 2004
Two major infrastructure projects in this period exposed the limitations of conventional coordinate systems.
High Speed 1, running from London to Folkestone, had been designed and constructed on a zonal system – a series of local grids – which proved insufficient for a project of its scale. The West Coast Main Line presented an even more serious problem – the route from London to Glasgow was simply too large for a zonal approach, and no standard projection existed that could cover it end to end.
Network Rail contacted Professor Jonathan Iliffe, Professor of Geomatics at University College London, to find a better way.
2005
To support the full-route 3D design of the West Coast Main Line ahead of the introduction of the new Pendolino trains, Network Rail commissioned Professor Iliffe to develop an entirely new coordinate framework for long rail corridors. That work led directly to the invention of SnakeGrid.
2008
Severn Partnership commissioned the first overseas SnakeGrid for a route-wide control network spanning Dublin to Cork, marking the methodology’s first application outside the UK.
2009
Building on the success of those early projects, SnakeGrids were designed for all the major rail corridors across the UK. The East Coast Main Line, Midland Main Line and Great Western route each received their own grids. Crossrail – at the time the largest infrastructure project in Europe – adopted SnakeGrid as its chosen coordinate system. In Northern Ireland, a single continuous coordinate system, NIR09, was designed to cover the entire rail network under one projection.
During this period the methodology continued to develop, with new capabilities introduced to extend and merge SnakeGrids. This allowed more complex rail corridors and connected infrastructure networks to be designed within the same framework.
Over the following decade, SnakeGrid became the accepted coordinate system for the UK rail network. Grids were commissioned for minor routes as well as major ones, and the approach was later mandated by Network Rail.
2012
The Channel Tunnel Rail Link – one of the original projects that had helped expose the need for a new approach – received its own SnakeGrid, this time to support ongoing maintenance and renewal work.
2014
Two of the most significant infrastructure schemes in the country adopted SnakeGrid for their coordinate systems. HS2 and East West Rail both required a framework capable of handling the scale and complexity their routes demanded.
2016 – 2020
As the benefits of the SnakeGrid approach became clear beyond rail, the methodology was adopted across other sectors. A pipeline project in the Lake District, road schemes in Wales and Scotland, and a mining and tunnelling project in the North East of England all used SnakeGrid grids.
A secondary format for the SnakeGrid parameters was also developed during this period, opening access to virtually any geospatially enabled software on the market.
2023
Having worked with SnakeGrid for many years across a range of infrastructure projects, Severn Partnership became the official licensing partner for the SnakeGrid framework, with UCLB granting the licence to support and develop the offering. The arrangement marked an important step in the continued development, governance and international adoption of SnakeGrid.
2023 – 2026
In the years following the licensing agreement, Severn Partnership delivered a growing portfolio of SnakeGrid work. The East West Rail grid was extended towards Cambridge. New grids were provided for Network Rail, and further work was completed in Ireland for Irish Rail, including a new radial grid for the Dart+ project. The secondary parameter format was generated for older grids, and Sizewell C adopted a SnakeGrid for its construction area and its interfaces with existing national infrastructure.
Throughout this period, Severn Partnership also led industry and supplier engagement to raise awareness of the approach and support its implementation on new projects.
2026 Onwards
Work is underway on a knowledge hub to support understanding and practical implementation for new clients. Internationally, growing interest from infrastructure projects abroad is opening new opportunities, as teams look to improve workflows on increasingly complex schemes.
From a single route to a national standard
For a while, the West Coast Main Line was the whole of it: one grid, one very visible project. But the problem it solved wasn’t unique to that line, and the grids started to multiply. HS2 got one, then renewals across Network Rail’s routes, and before long SnakeGrid was the coordinate system most rail work in Britain reached for by default. Anything long and linear runs into the same distortion, so it moved past the railways too, onto highways and pipelines, and beyond Britain onto projects across Europe and further afield.
SnakeGrid provides one continuous grid from end to end, with so little distortion that the earth almost seems flat. It quietly absorbs the curvature so nobody on site has to.
Some of the UK’s most complex projects run on it. HS2, Crossrail, the Transpennine Route Upgrade and more have all adopted SnakeGrid coordinate systems, and for long, linear work it’s the first system most surveyors and engineers turn to.
Provided by the Severn Partnership
SnakeGrid is now provided by the Severn Partnership, one of the UK’s leading multi-disciplinary surveying practices, working in partnership with UCL Ventures (formerly UCLB). Each grid is still built for the specific route it covers, and the Severn Partnership’s expert team supports the surveyors and contractors working to it. Jonathan Iliffe, now an honorary associate professor at UCL, is still involved.
Our team
Built by academics and delivered by surveyors, the two have worked hand in hand since day one. Meet the geospatial experts behind the SnakeGrid you see today.
Dr. Jonathan Iliffe
About Jonathan
Jonathan Iliffe is the inventor and developer of the SnakeGrid concept. Until his retirement from UCL in 2022, he was a senior lecturer in geodesy and head of the Geomatics Section in the Department of Civil, Environmental & Geomatic Engineering.
After obtaining his PhD Jonathan spend 2 years at CERN developing survey software for the Large Electron-Positron Collider before joining UCL. Alongside teaching and his role as programme lead, Jonathan’s expertise in geodesy and coordinate reference systems led to several calls to act as a geodetic consultant for industry and government around the world.
Closer to home Jonathan has also worked closely with the Ordnance Survey and UK Hydrographic Office as well as maintaining a continual involvement with the rail industry which he has supported through the development of the SnakeGrid solution. The SnakeGrid approach has been so successful in UK that it is now the de facto standard for Network Rail and the go to solution for projects such as HS2 and Crossrail.
Jonathan is also the co-author, with Roger Lott, of Datums and Map Projections, a textbook found on a good many surveyors’ shelves. His work on SnakeGrid, alongside projects like OSGM02 and VORF, earned him the Institution of Civil Engineering Surveyors’ Richard Carter Prize in 2008.
Dave Dampier
About Dave
Dave is a technical manager at Severn Partnership and the one of the leads for the provision of SnakeGrid services.
Following the completion of his degree, Dave has worked across the survey industry and has extensive experience in all aspects of the rail sector.
This has given Dave a strong foundation in survey principles and methods to which he has added a specialism in track measuring devices and scanning systems and their use for determining track geometry and clearance information as well as track maintenance applications.
With knowledge spanning both the survey and design worlds Dave has a good understanding of the impacts coordinate systems can have on projects and why giving them more consideration can brin substantial benefits.
Alongside his technical role at Severn Partnership, Dave works with Richard Day developing SnakeGrid solutions and working towards bringing its many benefits to the wider industry.
Richard Day
About Richard
Richard is a Principal Geospatial analyst at the Severn Partnership and one of the leads for the provision of SnakeGrid services.
After obtaining a Masters degree in Civil Engineering from Loughborough University, Richard combined his love of maps and the outdoors with engineering for a career in the survey industry which has involved many roles throughout the lifecycle of projects, from inception and data collection to setting out and the ongoing maintenance of project reference frames.
Through this Richard has developed an extensive knowledge of coordinate systems, control networks and survey methods and now supports clients and the project delivery teams with technical guidance and survey strategy.
This broad range of experience has also confirmed that the projects coordinate system is fundamental its success as it forms the basis of all design and construction information, although it is often little thought about which is something we hope to change!
Following the collaboration with UCLB, Richard now works closely with Dave Dampier designing SnakeGrids for projects and working towards improving awareness of the importance of coordinate systems across the industry.
