Home Natural Resource Management Call for sea change in British coastal mapping

Call for sea change in British coastal mapping

Integrating land mapping, marine charts and geological information around Britain’s coastline can be a huge boon to both public authorities and businesses, greatly improving coastal management and potentially saving millions of pounds in costs. – That is the conclusion of a two-year project which has just completed trials to unify digital mapping of the land, sea and geology of Southern England – from Shoreham in West Sussex to Lyme Regis in Dorset, including the Isle of Wight – along with areas of coastline around the Firth of Forth in Scotland and Milford Haven (Wales).

Now the three partners behind the Integrated Coastal Zone Mapping Project are seeking funds to create nationally-consistent data of the entire 18,000 kilometre (11,000 mile) coastline of Britain. The project was launched in 2001 when the government offered funds from HM Treasury’s Invest to Save Budget to underpin the ICZMap project, set up jointly by Ordnance Survey, the UK Hydrographic Office and the British Geological Survey. The aim was to create the first-ever unified digital base mapping combining onshore and offshore features and assess the benefits of developing such integrated mapping for the whole country.

The three partners were joined in a project steering group by other professionals and academics along with bodies such as the Environment Agency, port operator ABP(Mer), local authorities represented by the Isle of Wight Council, and Defra (the government’s Department for the Environment, Food and Rural Affairs).

ICZMap could potentially help thousands of coastal users, including harbourmasters, engineers, boat users and those responsible for environmental management, coastal conservation or new developments.

More than 500 organisations, companies and authorities have expressed interest in the potential benefits of ICZMap. Local authority policy makers, who have traditionally had no overall template to help them monitor and plan developments, which affect both land and sea, particularly welcome the initiative. Authorities that are responsible for implementing new European Union legislation covering the management of coastal zones say such tasks would be easier and more cost-effective to carry out using ICZMap. A survey carried out during the study showed that 85% of possible users said unified data would be helpful to them and supported its use in shoreline management plans.

Maps and charts along the coast of Britain are created at different scales and projections and held in different formats by one or more of the three bodies, and in the three trial areas a buffer stretching 20km offshore and 5km inland was adopted for integrating existing data.

The 44-page report from the two-year study shows that there is agreement that the latest and most detailed Ordnance Survey digital mapping – OS MasterMap – should be foundation data for the coastline in ICZMap, with UKHO and BGS data adjusted to align with it. To enable this to happen on a wider scale, Ordnance Survey will need to create a continuous Mean High Water (MHW) line in its detailed digital data – at present the data is broken by representations of features like piers, groins, bridges and harbour walls. It was also agreed that the delineation of Mean High Water (MHW) and Mean Low Water (MLW) around the coast would be the one based on Ordnance Survey data.

A common vertical referencing system covering land heights and sea depths was also created for cartographic purposes and has been based on the fixed Ordnance Datum Newlyn (ODN), with UKHO Chart Datum (CD) – recorded at 340 places around the coast in the trial areas – related to it. However, further technical and mathematical work is needed to implement common vertical referencing further off shore; the necessary work on this will be led by UKHO with input from other information providers.