Map Once, Use Many Times

IWG-OCM Standard Ocean Mapping Protocol

The draft SOMP is currently open for public comment through June 2, 2023: The comment deadline has been extended to July 28, 2023. The current Federal Register Notice is available. Public comment can be submitted via email to, with "Public Comment on Draft SOMP" in the subject line of the message.

Ocean mapping data is required to meet many federal government missions. To make the most of every survey mile collected, the IWG works with partners on mapping activities and data collection. Essential partners include the states, tribes, academia, private industry, non-profit organizations, and many others. In order to quickly and efficiently collect, process, and publish as much data as possible, a standardized collection protocol is needed. This protocol guides all the partners in data acquisitions to ensure the widest utility of the data, minimize duplication of effort, and to quickly and efficiently collect, process, and publish as much data as possible into archives and databases. National data standards and best practices will be used, as required by the Geospatial Data Act of 2018. This protocol should be updated by the IWG-OCM every five years to take advantage of innovative new technologies as they arise. Below are details of the featured specifications:

The bathymetric data section of the SOMP will focus on procedures for collecting, processing, and delivering bathymetry acquired by multibeam, single beam, split beam, and phase-discriminating sonar, and LIDAR systems. This SOMP chapter will summarize best practices for positioning, system calibration and QC/QA techniques, coverage and resolution, uncertainty, tides and water levels and general gridded data specifications.

Common standards for acquiring and processing acoustic seafloor backscatter data have not been widely established leaving user communities (e.g, marine hydrographers, biologists, geologists, managers etc.) with overlapping requirements for seafloor acoustic backscatter data and metadata. The backscatter data section of the SOMP will focus on establishing common backscatter acquisition and processing methods, acoustic signal corrections and image processing steps. The SOMP will address known user needs and leverage existing guidelines and recommendations from GeoHab Backscatter Working Group, as well as expert input from government, industry, academic institutions and other relevant bodies.

The subbottom profiling section will focus on common system types, practical survey design, conventional acquisition procedures, processing protocols, data formats, and publication of subsurface imaging data. The chapter will describe the standard operating procedure for the use of single channel acoustic systems that commonly operate in the 0.2 to 24 kHz frequency range to remotely image the surface morphology and nearsurface stratigraphy.

The side-scan sonar chapter of the SOMP will focus on collecting, processing, and delivering side-scan sonar data. This SOMP chapter will summarize best practices for acquisition standards and system set-up, range scales, frequencies and ping rates, coverage requirements, positioning, system calibration, QA/QC techniques, and how to derive products.

The water column echosounding section will focus on collecting, processing, and delivering raw and interpreted backscatter from singlebeam and multibeam echosounders. This SOMP chapter will summarize best practices for system configurations, operating frequencies and depth ranges, system calibration, QA/QC techniques, and analysis and interpretation of backscatter. While water-column echosounders have decades of use in fishery assessments, this session will focus on characterizing backscatter in support of mapping, exploration and characterization such as oceanographic or geophysical features, biological scattering layers or interpreting seabed biotopes using fishery echosounders.

A magnetometer is used to detect variations in the Earth's total magnetic field, which is comprised of the vector sum of geological (earth-based) sources, heliophysical (external) sources, and ferromagnetic objects. This sensor has many applications such as geomagnetism, structural geological mapping, energy and mineral exploration, archaeology, and munitions detection; data analysis can point to discrete anomalies on the earth's surface or seafloor and in shallowly buried contexts. The magnetometer section will focus on general magnetic theory as it relates to anomaly detectability, factors that influence data quality, instrument configuration and selection, platforms, coverage specifications, testing calibration, and resolution/line spacing based on survey objectives.

The data management section will focus on procedures for effective data management, metadata, and archive techniques that provide the pillars for data to be utilized and shared now and into the future. This SOMP chapter will summarize data management protocols applied to each SOMP theme. Examples include: quality assurance, acceptance criteria, validation, metadata standard templates, accessibility, and submission to archives (file formats, metadata and file structure).