In a separate NODC Accession, 0051060, text data files are given of the substrate types and coverages as derived objectively from photographic images using PhotoGrid, a software package which analyzes random points on images of coral reefs and substrate.
Resource Description: NODC Accession Number 0056791
Prior to the switch, the compatibility of the methods was assessed through intercalibration, using both methods (video and digital still images) at a large number of sites (30) that encompassed a wide range of coral cover. Once the methods proved compatible, all subsequent surveys were conducted with digital cameras. Non-overlapping digital stills are taken to assess the characteristics of benthic populations. High resolution digital images are taken along a 10 m transect using an Olympus 5050 zoom digital camera with an Olympus PT050 underwater housing. The camera is mounted to an aluminum monopod frame, 1.7 m from the substrate to provide a 50x69 cm image. A 6 cm bar provides a measurement scale. The software program PhotoGrid (Bird 2001) is used to quantify percent cover, richness and diversity of corals, algal functional groups and substrate cover. Images are downloaded and the 20 non-overlapping images from each 10 m transect are imported into PhotoGrid where 50 randomly selected points are projected onto each image for a total of 1,000 points per transect.
INSTRUMENT TYPES: digital camera: Olympus 5050 zoom digital camera
REFERENCES: Brown, E, E Cox, B Tissot, K Rodgers, and W Smith (1999). Evaluation of benthic sampling methods considered for the Coral Reef Assessment and Monitoring Program (CRAMP) in Hawaii. International Conference on Scientific Aspects of Coral Reef Assessment, Monitoring, and Restoration. April 14-16, Ft. Lauderdale, FL.
Green, R H and S R Smith (1997). Sample program design and environmental impact assessment on coral reef. Proc 8th International Coral Reef Symposium. 2: 1459-1464.
McCormick, Mark 1994. Comparison of field methods for measuring surface topography and their associations with a tropical reef fish assemblage. Marine Ecology Progress Series 112: 87-96.
Directory tree is as follows:
data/ 0-data/ this denotes original files/directories as received by NODC
file: MHI2007sitedates.csv comment: Survey specifics (location, dates, depths)
subdirectories: 0-data/ 07 KaHan Images/ 07KaHan03m/ transect along 3m isobath filename: 07KaHan03mttff.JPG tt: transect number ff: frame number 07KaHan10m/ transect along 10m isobath
0-data/ 07CRAMP_SI/ Output from PhotoGrid for various Maui sites SI denotes selected images for analysis by PhotoGrid
transect file name template: Convention is yyIISSSDDm yy : last two digits of year II : island (sometimes left off) SSS : site (see STATIONS above) DDm : depth in meters TT : transect number ff : frame number (sometimes TT is left off if only one transect, and sometimes .SI is suffixed).
within 07CRAMP_SI/ there are subdirectories yyIISSSDDm_SI/ subdirectory for depth DDm yyIISSSTT_SI/ secondary subdirectory for transect TT filename: yyIISSSDDMTTff.jpg
0-data/ 07MaMah03m/ 3m depth at Mahinahina, Maui, filename template above 07MaMah10m/ same for 10m
0-data/ Ahii Kinau PhotoGrid Images/ all images from Ahii Kinau, Maui subdirectory: AHItt/ where tt: transect number
filename: AHIttTransectff.JPG tt: transect number ff: frame number
0-data/ Kamiloloa03m/ 3m depth at Kamilioloa, Molokai, filename template above Kamiloloa10m/ 10m depth
0-data/ Palaau03m/ 3m depth at Palaau, Molokai, filename template above Palaau10m/ 10m depth