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    • Coral Reef Structural Complexity derived from Structure-from-Motion (SfM) imagery collected at Stratified-Random Sites (StRS) across the U.S. Pacific since 2019

    Metadata Updated: December 27, 2025

    The data described here are structural complexity estimates derived from Structure-from-Motion (SfM) benthic habitat imagery from diver transect surveys conducted at stratified-random sites (StRS) by the Pacific Islands Fisheries Science Center (PIFSC) Ecosystem Sciences Division (ESD) as part of the NOAA National Coral Reef Monitoring Program (NCRMP). The coral reef photos, collected by scuba divers, are used to generate 3-dimensional models, digital elevation models (DEMs) and orthomosaics using Agisoft Metashape photogrammetric software. The digital elevation models were analyzed in R studio to derive estimates of habitat structural complexity, using metrics such as: rugosity, fractal dimension, and height range, among others. The source imagery is archived and described separately at https://www.fisheries.noaa.gov/inport/item/63095. The SfM surveys are part of the Rapid Ecological Assessment (REA) surveys for corals and fish conducted during ESD-led NCRMP missions. Sites were imaged using underwater cameras along 3x20m (3x13m for sites deeper than 18m) transects across the U.S. Pacific Island areas beginning in 2019. Please refer to the Lineage section for SOPs -- 2019 and 2022 have slightly different processing steps. Complexity metrics were estimated for each site within five or six 4m2 DEM sampling plots, which can then be averaged for the site. Rugosity is measured as the ratio between surface area and planar area within a sampling plot, Fractal dimension is measured using the variation or standard deviation method (see Lineage section below), and height range is measured as the difference between the deepest and shallowest point within a sampling plot.
    A stratified random sampling (StRS) design was employed to survey the coral reef ecosystems across the U.S. Pacific Regions (Hawaiian Archipelago, Mariana Archipelago, American Samoa, and the Pacific Remote Island Areas). The survey domain encompassed the majority of the mapped area of reef and hard bottom habitats in the 0-30 m depth range. The stratification scheme included island, sub-island sector, reef zone, and depth in all regions, as well as habitat structure type. Allocation of sampling effort was proportional to the strata hardbottom area. The StRS design effectively reduces estimated variance by sampling more sites with larger hardbottom area and variance.

    Access & Use Information

    License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

    Downloads & Resources

    Dates

    Metadata Date December 18, 2025
    Metadata Created Date December 27, 2025
    Metadata Updated Date December 27, 2025
    Reference Date(s) 2022-11 (creation), 2025 (publication)
    Frequency Of Update asNeeded

    Metadata Source

    Harvested from NMFS PIFSC

    Other Data Resources

    Additional Metadata

    Resource Type Dataset
    Metadata Date December 18, 2025
    Metadata Created Date December 27, 2025
    Metadata Updated Date December 27, 2025
    Reference Date(s) 2022-11 (creation), 2025 (publication)
    Responsible Party (Point of Contact, Custodian)
    Contact Email
    Guid gov.noaa.nmfs.inport:67851
    Access Constraints Cite As: Pacific Islands Fisheries Science Center, [Date of Access]: Coral Reef Structural Complexity derived from Structure-from-Motion (SfM) imagery collected at Stratified-Random Sites (StRS) across the U.S. Pacific since 2019 [Data Date Range], https://www.fisheries.noaa.gov/inport/item/67851., Access Constraints: None, Use Constraints: Please cite NOAA Fisheries, Ecosystem Science Division (ESD) when using the data. Example: Ecosystem Science Division; Pacific Islands Fisheries Science Center, 2022: Structure from Motion (SfM) Structural Complexity derived from Stratified Random Site (StRS) Imagery across the US Pacific since 2019, https://www.fisheries.noaa.gov/inport/item/67851., Distribution Liability: While every effort has been made to ensure that these data are accurate and reliable within the limits of the current state of the art, NOAA cannot assume liability for any damages caused by errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty.
    Bbox East Long -154.8042
    Bbox North Lat 22.20357
    Bbox South Lat 19.07632
    Bbox West Long -160.2518
    Coupled Resource
    Frequency Of Update asNeeded
    Harvest Object Id 890e55ea-3b46-41fe-ba24-6e1e2849dbae
    Harvest Source Id c0beac72-5f43-4455-8c33-1b345fbc2dfe
    Harvest Source Title NMFS PIFSC
    Licence NOAA provides no warranty, nor accepts any liability occurring from any incomplete, incorrect, or misleading data, or from any incorrect, incomplete, or misleading use of the data. It is the responsibility of the user to determine whether or not the data is suitable for the intended purpose.
    Lineage The benthic SfM survey methodology, employed by the NOAA Ecosystem Sciences Division (ESD), began in 2019. Benthic imagery is collected at stratified random sites and generated into image maps using Agisoft Metashape software. Resulting digital elevation models are used to estimate three habitat structural complexity metrics: rugosity, fractal dimension, and height range.
    Metadata Language eng
    Metadata Type geospatial
    Old Spatial {"type": "Polygon", "coordinates": [[[-160.2518, 19.07632], [-154.8042, 19.07632], [-154.8042, 22.20357], [-160.2518, 22.20357], [-160.2518, 19.07632]]]}
    Progress onGoing
    Spatial Data Service Type
    Spatial Reference System
    Spatial Harvester True
    Temporal Extent Begin 2019-04-21
    Temporal Extent End 2019-08-06

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