Wendt, Hans; Roelfsema, Christiaan M; Comley, James (2013): Benthic and substrate cover data derived from photo-transect surveys in Kadavu, Fiji on June, July, October and November 2009 [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.831257,

---

In supplement to: Roelfsema, Christiaan M; Phinn, Stuart R; Jupiter, Stacy D; Comley, James; Albert, Simon (2013): Mapping coral reefs at reef to reef-system scales, 10s–1000s km**2, using object-based image analysis. International Journal of Remote Sensing, 34(18), 6367-6388, https://doi.org/10.1080/01431161.2013.800660

Underwater georeferenced photo-transect survey was done on June 17-30, July 1-21, October 7-29 and November 5-9 2009 at different sections of the reef flat, reef crest and reef slope in Kadavu, Fiji. For this survey a snorkeler or diver swam over the bottom while taking photos of the benthos at a set height using a standard digital camera and towing a surface float GPS which was logging its track every five seconds. A standard digital compact camera was placed in an underwater housing and fitted with a 16 mm lens which provided a 1.0 m x 1.0 m footprint, at 0.5 m height above the benthos. Horizontal distance between photos was estimated by three fin kicks of the survey diver/snorkeler, which corresponded to a surface distance of approximately 2.0 - 4.0 m. The GPS was placed in a dry-bag and logged its position as it floated at the surface while being towed by the photographer. A total of 8323 benthic photos were taken. A floating GPS setup connected to the swimmer/diver by a line enabled recording of coordinates of each benthic (Roelfsema and Phinn, 2009).

Approximation of coordinates of each benthic photo was done based on the photo timestamp and GPS coordinate time stamp, using GPS Photo Link Software (http://www.geospatialexperts.com). Coordinates of each photo were interpolated by finding the gps coordinates that were logged at a set time before and after the photo was captured.

Benthic or substrate cover data was derived from each photo by randomly placing 24 points over each image using the Coral Point Count excel program (Kohler and Gill, 2006). Each point was then assigned to a specific cover type, which represented the benthic feature beneath it. Benthic cover composition summary of each photo scores was generated automatically using CPCE program. The resulting benthic cover data of each photo was linked to gps coordinates, saved as an ArcMap point shapefile, and projected Universal Transverse Mercator Zone 60 South and Datum used was WGS 84.