Integrated Ocean and Coastal Mapping

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Ecological Classification - CMECS

Coastal and Marine Ecological Classification Standard logo

The Coastal and Marine Ecological Classification Standard (CMECS) is a structured catalog of ecological terms that also provides a framework for interpreting, classifying, and inter-relating observational data from all types of sensors and platforms. The CMECS vocabulary describes coastal and marine environments from the head of tide in estuaries to the depths of the oceans and Great Lakes, and offers an umbrella under which a national coastal and marine ecological classification can grow and evolve.

Endorsed by the FGDC in 2012, CMECS builds upon approaches from published national, regional, and local habitat classification procedures. As an FGDC standard, federally funded projects working with environmental data in marine settings should use CMECS as their primary classification system or include CMECS attributes for their data.

Download the CMECS Document
For the complete description of the standard, the framework, and the units

CMECS partners diagram

CMECS was developed, tested, and distributed for peer review over a period of several years by a core group with members from the NOAA Office for Coastal Management, NOAA Office of Habitat Conservation, U.S. Environmental Protection Agency, U.S. Geological Survey, and NatureServe working with hundreds of scientists and coastal managers. The collaboration continues in the CMECS Implementation Group (IG), which

  • Promotes and provides guidance for its use
  • Coordinates standard maintenance and updates
  • Facilitates working relationships between CMECS users

For technical assistance, general guidance, or to offer suggestions, contact the Implementation Group at

Collage of various coastal and ocean stakeholder interests depicted in callout windows, implying communication

Connect with others in the CMECS user community through the CMECS Community Forum, where you can post questions, check on upcoming events, explore implementation strategies used by your peers, and share your successes. You’ll also find CMECS-related publications, presentations and posters from recent conferences, and the latest information on how to submit feedback and suggestions for improving CMECS.

The six elements of CMECS represent the different aspects of the seascape, starting with the broadest systems and narrowing to the most detailed physical and biological features associated with a specific habitat type.

The foundation of CMECS are ecological units. A unit is any defined entity occurring at any level in the classification hierarchy. Individual units are organized within the four thematic habitat components for water column, biotic, substrate, and geoform data.

Biogeographic and aquatic settings are differentiated by features influencing the large-scale distribution of organisms, and by salinity, tidal zone, and proximity to the coast. (marine, estuarine, and lacustrine).

Components and settings can be used independently of each other or in combination depending on the observation methods used and research objectives.

Modifiers are additional terms that can be used on a case-by-case basis where CMECS does not provide the necessary level of description for the data. Users can define and add their own additional modifiers as needed. This option for customization provides flexibility so that CMECS can meet the needs of individual projects.

A biotope is a classification that combines biotic and abiotic features to fully characterize the unique combination of environmental variables and associated species that make up a particular habitat type for a specific area.

Image illustrates how the individual CMECS settings and components can be combined to form biotopes, which are areas of uniform environmental conditions providing a living place for a specific assemblage of plants and animals.
The complete CMECS unit vocabulary definitions can be found in the CMECS Document, and in the searchable CMECS Catalog Database.

Click on the images below to see how each site might be classified using the different settings, components, and modifiers of the CMECS system. Click to download the complete gallery.

Share your classification by emailing the CMECS Implementation Group at

Photo of underwater corals with the text Florida Keys, Florida, USA.
Aerial view of Narragansett Bay with text Narragansett Bay, RI, USA.
Underwater image with text Punta Cana, Dominican Republic.
Underwater image with text Long Beach Harbor, California, USA.
Image if York River, with text York River, Virginia, USA.
Image of intertidal area with text Buzzards Bay, Massachusetts, USA.
Image of intertidal area and seagrass with text Long Island Sound, New York, USA.
Image of underwater kelp forest with text California Coast, USA.
Underwater seafloor image with text Blake Ridge, South Atlantic Bight.
Image of shore with driftwood with text Capers Island, South Carolina, USA.
Underwater coral image with text Dry Tortugas, Florida, USA.
Image of shore during low tide with text Lower Laguna Madre, Texas, USA.
Image of shore during low tide with text Upper Laguna Madre, Texas, USA.
Image of coastal area with text Hempstead Bay, New York, USA.
Image of coastal area with text Gray's Sound, South Carolina, USA.

The resources in this section provide guidance for applying CMECS in fieldwork and mapping. They are not requirements, and may be modified or retired according to changes in technology and the standard itself.

Additional resources can be found on the CMECS Community Forum Site

Applying CMECS to Data

Proposed CMECS Data Structure – A short outline of how CMECS data could be organized in an ESRI file geodatabase structure.

Coding Approach and Code Set – Spreadsheets with the code set for the entire CMECS system and a short document explaining how the codes can be applied as attributes for observations and mapping.

Classifiers Document – Document that presents the physical, chemical, and biological characteristics necessary to assign CMECS unit labels to data. This is of value to those collecting source data that will later be used to develop CMECS habitat maps.

Nomenclature Document – Several examples of how CMECS unit names from several components can be compiled into terminology for CMECS-derived units.

CMECS Concept Map – A graphical representation of the CMECS component framework and hierarchical structure. Useful for understanding how the components relate to each other and which ones might be appropriate for specific projects.

Crosswalking Other Classifications to CMECS

Crosswalking is the process of converting attributes or data from one classification scheme to another. This may be necessary when integrating legacy data into a new system, or when assembling disparate data sets into a larger framework.

Conceptual crosswalks describe the definitional relationships between units in two classification systems. Data crosswalks involve re-attribution of digital spatial data. Data crosswalks build on the conceptual relationships but also are influenced by spatial scale and observation methods.

Appendix H of the CMECS 2012 document describes best practices for crosswalking data to CMECS

Conceptual crosswalks from commonly used classification systems to CMECS:


CMECS Crosswalk Tool. A downloadable tabular analysis tool developed by the NOAA Office of Coastal Management that translates existing spatial benthic habitat data sets into CMECS compliant feature layers. The tool runs in Esri ArcMap (desktop) software.

This online map allows users to explore the geographic distribution of projects that use CMECS, which have been organized into the categories below:
  • Mapping Projects – Projects where source data were analyzed or interpreted directly to produce CMECS data from the outset.
  • Data Integration Projects – Projects where several existing data were integrated to produce a seamless map or establish historical trends.
  • Crosswalks – Projects where existing or new data classified under another system were translated to CMECS.
  • organizing framework for multiple smaller-scale efforts and data sets.

Many other programs and projects that use CMECS in a variety of ways. Visit the websites below to learn more about their applications and methods.

Additional examples of CMECS application, including publications and presentations from recent conferences, can be found at the CMECS Resources of the Community Forum Site.

CMECS was designed as a dynamic content standard that relies on continual user engagement to keep up with advances in scientific knowledge, technology, and the needs of the coastal management communities. The Dynamic Standard Process (DSP), developed and overseen by the CMECS Implementation Group, is a means to gather feedback and recommendations from users for improvements to CMECS. While many aspects of this process are still being refined, the DSP has, and will continue to have, these standard characteristics:
  • Clear criteria and requirements for proposing and evaluating a change to CMECS
  • The involvement of subject-matter experts when needed to ensure scientific validity of any change
  • Different levels of review depending on the scale of the proposed change
  • Feedback loops to proposers and reviewers
  • The ability to track and maintain lineage between old and new versions of CMECS
  • A decision-dissemination element to share the results
Flow diagram of the CMECS dynamic standard process.

See the CMECS Community Forum site’s CMECS Update Information page for up-to-date information on how to submit your suggestions for improving CMECS and to access guidance documents for submitters and reviewers.