Ships and cargoes – guidance

Share hydrographic data with Maritime and Coastguard Agency (MCA)

Find out about MCA’s bathymetric data collection programme, how to share data with MCA, and guidance for offshore developers.


This guidance tells you where you can see the results of the UK civil hydrography programme (CHP), and where other government organisations have surveyed (and are planning to survey) around the UK.

It also outlines how to share the results of your hydrographic surveys with MCA, and gives guidance for offshore developers planning to undertake surveys.

About UK civil hydrography programme (CHP) data

MCA has been collecting multibeam bathymetric data under the CHP since 2004. Since then the CHP has surveyed around 12% of UK home waters.

CHP data: view on UK Hydrographic Office (UKHO) data archive

Bathymetry collected under the CHP is freely available under an Open Government Licence (OGL).

View it through the UKHO’s bathymetry data archive centre portal.

CHP data: view on Google Earth

CHP data is also available using Google Earth. This shows the results of seabed mapping carried out under the CHP using multibeam echo sounder technology.

Google Earth makes CHP data:

  • more accessible – no need for complicated software and systems
  • easier to understand and visualise

The CHP Bathy Atlas uses a specially developed bathymetry colour map to emphasise the results of seabed mapping carried out under the CHP, using multibeam echo sounder technology.

These multibeam surveys are split into:

  • 11 geographic regions
  • 4 routine resurvey (RRS) areas from the left-hand ‘places’ pane

New surveys and layers (and some of the legacy datasets, when processed), will be added to this pane when they’re completed.

Install Google Earth on your computer before launching the Bathy Atlas. Please note: it may take a few minutes to download the survey results the first time.

Download the survey data zip file

Guide to using the CHP bathy atlas

This file may not be suitable for users of assistive technology. Request a different format.

If you use assistive technology and need a version of this document in a more accessible format, please email Please tell us what format you need. It will help us if you say what assistive technology you use.

Use CHP data and images for reports and publications

Please follow the requirements of the Open Government Licensing Framework and include this attribution:

Contains Maritime & Coastguard Agency data © Crown copyright

CHP data and images should not be used for navigation.

Government multibeam data: where it exists and where future surveys are planned

MCA and the Department for Environment, Food and Rural Affairs (Defra) have worked together to create a memorandum of understanding (MoU) covering bathymetric survey data and data gathering. It’s helped increase offshore survey efficiency for government organisations.

The main aims of the MoU are to:

  • exchange (for free) existing and future multibeam echo sounder data and backscatter data between the organisations taking part
  • set a method to make sure future surveys (by participating organisations) are programmed in a way that avoids survey effort being repeated

Organisations that have signed the MoU include:

  • Defra
  • UKHO
  • Agri-Food and Biosciences Institute (AFBI)
  • British Geological Survey (BGS)
  • Centre for Environment Fisheries and Aquaculture Science (CEFAS)
  • Joint Nature Conservation Committee (JNCC)
  • Marine Scotland
  • Ministry of Defence (MoD)
  • Natural England (NE)
  • Natural Resources Wales (NRW)
  • Scottish Natural Heritage (SNH)
  • The Crown Estate (TCE)

See multibeam data holdings and planned survey programmes from other government bodies

Download the JNCC survey areas shapefile

Download the Cefas survey areas shapefile

Download the BGS survey areas shapefile

Download the NE survey areas shapefile

Download the MoD survey areas shapefile

Download the CE survey areas shapefile

Download the NRW survey areas shapefile

Fill in the MoU data request form to request any of the datasets listed in the shapefiles (but only if your organisation has signed the hydrographic data sharing MoU).

Viewing shapefiles

Geographic Information System (GIS) software can import and display the ESRI shapefile format, or you can download ESRI’s free shapefile viewer ArcGIS Explorer.

Share hydrographic data with the MCA and help improve mariner safety

MCA will pass data to the UKHO from the hydrographic surveys you perform. This will help them compile new or updated nautical charts, and so help improve safety for mariners.

Your survey does not need to be carried out to full charting standards to be of use. Even without a full search for dangers, a modern survey can improve on our knowledge of the seabed.

There will be no legal liability on you for the way that we use your data.

Data gathering: MCA guidelines

To make the bathymetry data as useful as possible, MCA recommend that you render and send it in digital form, especially data which fully complies with all aspects of International Hydrographic Organization (IHO)S44 Order 1a.

Data in the following formats is welcome:

  • Caris HDCS directory (i.e. HIPS)
  • Generic Sensor Format or Fledermaus PFM
  • ASCII xyz

The data is also useful if:

  • full-density digital data is supplied – before any gridding, binning or tinning is applied. (If gridded datasets have been created, you can send these to MCA)
  • the soundings are reduced using observed tides (not predicted tides from tide tables)
  • depths are referenced to UKHO chart datum for the area

Any spurious data must be cleaned from the final dataset you send us. Digital data with rejected soundings can be included, but must be flagged as deleted. Please state the method used in any data-cleaning (e.g. shoal or median biased).

If you have it, also send MCA a report of the survey that describes how the data was gathered and processed, especially if it includes:

  • a list of the equipment and software used
  • how positioning equipment was set up, calibrated and used
  • how the echo-sounder transducer was set up and levelled, together with all sensor offsets
  • details of the horizontal datum to which the positions are referred (or the grid, if appropriate)
  • how tides were measured
  • how the tide pole or tide gauge was levelled
  • how depths were reduced to chart datum

Guidance for offshore developers doing hydrographic surveys

These guidelines are useful for developers when making consent applications which will have an impact on hydrography. They outline MCA’s requirements, the survey requirements, what to survey, and what data to send.

Contact MCA’s hydrography branch