The objective of this guide is to address specific issues in the archiving and preservation of survey data generated as part of marine archaeology projects and to provide guidance on the planning and creation of a digital archive. This guide has been informed by a number of existing documents and guidelines together with other guides created as part of this new series of Guides to Good Practice. Due to obvious similarities in a number of respects, this guide will reference heavily the Geophysical Data in Archaeology Guide and, rather than repeat material, will simply link to the relevant sections in the terrestrial geophysics guide where necessary. A number of other publications are also heavily referenced and constitute a body of 'recommended reading' that should accompany this guide.
The main documents referred to from this guide are:
This guide also draws on conclusions and approaches highlighted in English Heritage's recent work to address the specific issues surrounding long term preservation and dissemination of marine archaeological data as part of the Big Data project. Such issues are covered generally in the introductory 'Project Archive' section of these Guides and specific elements are highlighted in this guide's 'Big Data' section.
In addition to the sources mentioned above, this guide also draws on ADS involvement in the VENUS project. The VENUS project aimed to survey shipwrecks at various depths and to explore advanced methods and techniques of data acquisition through autonomous or remotely operated unmanned vehicles (ROVs) with innovative sonar and photogrammetry equipment. The project also covered aspects such as data processing and storage, plotting of archaeological artefacts and information system management. This work has resulted in a separate guide on best practice procedures for data acquisition, dissemination and archiving specific to the VENUS project which has then been partly incorporated into this marine survey guide.
As with the previous VENUS guide, it is not intended that this document be a comprehensive guide to all existing guidelines or technical advice that is available on the subject of documenting and preserving marine survey data. Rather, this guide should be seen as a source both of general information on the digital preservation of marine survey data and of references to additional online and published resources.
Within the last five years a significant number of major studies have been undertaken looking at the marine historic environment and maritime archaeology and archives. The quote above comes from the 2007 report 'Slipping Through The Net: Maritime Archives In Policy And Practice' produced by the UK's Institute for Archaeologists (IfA) Maritime Affairs Group and succinctly highlights the current situation with maritime archives in the UK. It is worth noting that this situation does not seem to be confined to purely archaeological marine data. The IfA report has led on to one of the most significant projects in the UK, and most relevant to this specific guide, the recent (2009) 'Securing a Future for Maritime Archaeological Archives' project carried out by the Hampshire and Wight Trust for Maritime Archaeology and the Institute of Field Archaeologists with support from the Archaeology Data Service and funding form English Heritage, Historic Scotland, the Royal Commission for the Ancient and Historic Monuments of Scotland and the Society of Museum Archaeologists. The project has produced three reports which have aimed to assess the current provisions for collecting and archiving maritime archaeological archives (including digital data) and to provide details of the types of archives being created, the current capacity for storing these and the current regulatory, curatorial and consenting processes involved in archive deposition. Some of the major conclusions of the project were that high numbers of digital archives were being created from marine projects (particularly through research and by archaeological contractors) and that much of this data remained unarchived and unavailable.
Marine data has also been highlighted in the Big Data project report (see above) as often generating large datasets (e.g. bathymetric data) which are comparatively costly to archive whilst also being difficult to disseminate. While this provides a barrier to preserving such data on one hand, on the other it highlights the importance of ensuring that this data is preserved, well documented and shared as it is equally difficult and costly to recreate (if recreating it is even an option).
In addition to assessing the current situation in the UK for maritime and marine data, a number of other projects and reports have recently been commissioned to look at addressing these current problems and developing strategies to ensure that maritime and marine research is effectively planned and prioritised and that the resulting data is accessible. English Heritage's 'Maritime and Marine Historic Environment Research Framework' for England  and Historic Scotland's (n.d) Towards a Strategy for Scotland's Marine Historic Environment are two such examples.
Despite the current situation, the importance of the marine historic environment has been recognised for a significant length of time. Within this, the role that digital data collection techniques such as remote sensing and geophysical survey can play in the management of the marine environment has also been in highlighted in guidelines produced by a number of national bodies and organisations (e.g. Roberts & Trow 2002, 24).
Although the current situation with archaeological marine and maritime data is far from ideal, a number of initiatives - both within and outside of archaeology - have made considerable progress towards the consistent recording and dissemination of marine data. One of the most significant initiatives in the UK to ensure that all types of marine data are made accessible has been the creation of the MEDIN (Marine Environmental Data and Information Network) partnership. MEDIN essentially acts as a UK portal for a number of organisations such as the British Geological Survey (BGS), British Oceanographic Data Centre (BODC) and the United Kingdom Hydrographic Office (UKHO), all of which act as DACS (marine data archive centres) with the aim of providing secure long-term storage for marine data. As mentioned above, MEDIN has produced a number of guidelines for archiving and creating metadata for marine datasets, some of which are highly relevant to data created through archaeological projects.
Within the US, a similar situation to the UK exists with the National Oceanic and Atmospheric Administration (NOAA) and its National Oceanographic Data Center (NODC) and National Geophysical Data Center (NGDC) providing archival functions and access to marine datasets as well as guidelines on documenting and deposit data.
Organisations such as MEDIN and NOAA, and their role in documenting and providing access to datasets, also highlight the importance of standardised metadata, particularly spatial metadata, and the national and global initiatives working towards the creation of standardised schema. The creation of standards such as ISO19115 along with localised implementations (e.g. North American Profile, UK GEMINI2 and INSPIRE) are equally applicable to marine datasets and can only aid in their discovery and reuse. Specific groups within the US, such as the FGDC Marine and Coastal Spatial Data Subcommittee  additionally illustrate a need to apply general spatial standards to the marine environment. The work of the Ocean Data Standards Pilot Project (ODS) also illustrates an attempt to tie up and formalise the adoption of such standards on an international level.
In terms of archaeology-specific initiatives, and in response to the current archive situation, the recommendation of bodies such as English Heritage that the deposit of archives (including digital data) must be a part of a project's dissemination strategy - and that survey data forms a key component of this archive - can only help in the securing of marine datasets (English Heritage 2010, 15-16). Additionally, certain bodies such as English Heritage require the reporting of projects that they fund through systems such as OASIS  which in turn can make data available to regional and national data holders (e.g. HERs, SMRs and the NMRs in the UK). In the case of OASIS, work is also currently underway to allow this metadata to also be accessible via the UK MEDIN portal.
 VENUS Guide to Good Practice