CAM-ERA – video beach monitoring at Tairua and Mokau

See www.niwa.co.nz/services/cam-era/ Purpose: Part of the Natural Hazards Programme. Research on beach processes. Monitoring beach state, shoreline position, beach use, wave conditions, bar conditions and rip currents.

Every hour during daylight time, 600 images (one every second for 10 minutes) are taken. The first of the 600 is saved as an individual image and posted on the website. The 600 images are averaged and saved as one image, which is also archived.

Two cameras at Pauanui (north and south end), one on Paku Hill overlooking Tairua Ocean Beach and two cameras at Mokau (one camera looking over river mouth and offshore bars, the other along the foreshore.

Tairua Camera: August 1997 - present Pauanui A & B: December 2000 - present Mokau A & B: June 1999 - present

Frequency of collection: Images are collected hourly and displayed on NIWA’s Internet site at http://www.niwa.cri.nz/services/cam-era.

There are a number of image processing techniques required to make use of the image for many purposes, including: Averaging: Some information that can be obtained from the images is not apparent from an individual image. For example, to find the position of the shorlein or offshore sand bars (from breaking wave patterns), 16 minutes of images (600 images) are taken every hour an can be averaged. In the resulting image, the average shoreline and average position of the bar become clearly visible. Rectification: the rectification routine takes an oblique image and converts it to a plan view by mathematical transformation using the orientation and position of the camera. Once the oblique images are rectified, the images become the equivalent of a vertical aerial photograph, which allows direct scaling of features such as high water marks and rip currents. Lens distortions: for detailed measurements (e.g. measuring wave parameters) distortions caused by imperfections in the glass and the way the surface is shaped need to be corrected. These distortions have been corrected using freely available software written by Janne Heikkila at the University of Oulu, Finland (Heikkila and Silven 1996). Gaps in collection: There are occasional gaps in the data when cameras or housings have been damaged. Data quality: Complicated aspects of data quality are available in the many publications listed in this metadata sheet.

digital image Digital Format: CD

Peer Reviewed Papers: Bogle, J., 2000: Video imaging techniques for quantitative data on bathymetry, wave period, and rips, and qualitative analysis of beach dynamics. University of Waikato thesis. Bogle, J.A., K.R. Bryan, K.P. Black, T.M. Hume and T.R. Healy (2001). Video Observations of Rip Formation and Evolution, Journal of Coastal Research, Special Issue 34, 117–127. Smith, R.K., and K.R. Bryan. Monitoring Beach Volume Using a Combination of Intermittent Profiling and Video Imagery. Journal of Coastal Research. Submitted in November, 2002. Bryan, K. R. and A. Swales (2003). Inferring bar position from video imagery of breaking waves at Tairua Beach, New Zealand, Coasts and Ports '03, Proceedings of the 16th Australasian Coastal and Ocean Engineering conference and the97th Australasian Port and Harbour Conference, Sept 9–12, Auckland, New Zealand, paper #20. Bryan, K. R., R. K. Smith and R. Ovenden (2003). The use of video camera to assess beach volume change between April and June 2001 at Tairua, New Zealand. Coasts and Ports '03, Proceedings of the 16th Australasian Coastal and Ocean Engineering conference and the97th Australasian Port and Harbour Conference, Sept 9–12, Auckland, New Zealand, paper #19.. Bogle, J.A., K.R. Bryan, K.P. Black, T.M. Hume and T.R. Healy (1999). Observations of geomorphic parameters using video images, Coasts and Ports '99, vol I, Proceedings of the 14th Australasian Coastal and Ocean Engineering conference and the 7th Australasian Port and Harbour Conference, April 14–16, Perth, Australia, 70–75. Conference Abstracts: MacDonald, I.T., K.R. Bryan and R.M. Gorman(2000). “ Measuring surfzone width from video images of beaches”, Abstract in Programme & Abstracts, August 30–September 1, Hamilton, New Zealand, New Zealand Marine Science Society Conference, p55. Bryan, K.R., I.T. MacDonald, and R.M. Gorman (2000). “Deriving robust methods for measuring wave frequency and angle using video imagery of waves”, Abstract in Programme & Abstracts, August 30–September 1, Hamilton, New Zealand, New Zealand Marine Science Society Conference, p25. Gorman, R.M. and K.R. Bryan (2000). “How video distilled the wayward bar: image analysis at the beach with empirical eigenfunctions”, Abstract in Programme & Abstracts, August 30–September 1, Hamilton, New Zealand, New Zealand Marine Science Society Conference, p38. Bogle, J.A., K.R. Bryan, K.P. Black, T.M. Hume and T.R. Healy (2000). “Video Observations of Rip Formation and Evolution”, Abstract in: Conference Program and Abstracts, April 24–28, Rotorua, New Zealand, International Coastal Symposium, p103. Bogle, J.A., K.R. Bryan, K.P. Black, T.M. Hume and T.R. Healy (1999). “Observations of rip currents using video images”, Abstract in: Programme and Abstracts, September 1–3, Wellington, New Zealand Marine Sciences Society Conference, p27. Bryan, K.R., R.M. Gorman, T.M. Hume and K.P. Black (1999). “A method for making detailed measurements of cusp spacing using sub-aerial video cameras”, Abstract in: Programme and Abstracts, September 1–3, Wellington, New Zealand Marine Sciences Society Conference, p33. Other Publications: Bryan, K.R., T.M. Hume and G. Payne (2000). The Cam-Era Final Report, prepared for The Ministry for the Environment, NIWA Client Report, MFE00212, 29pp. Hume, T.M., G.W. Payne and K.R. Bryan (1999). Cam-Era Product Development Workshop, prepared for The Ministry for the Environment, NIWA Client Report, MFE00212, 8pp. Hume, T.M., G.W. Payne, K.R. Bryan and K.P. Black (1999). The Cam-Era Network, NIWA Internal Report #59, 18pp. Payne, G., S. Stephens, K. R. Bryan, P. Hesp and B. Gibberd, 2003, New Zealand’s Sandy Coasts, produced by National-Institute of Water and Atmospheric Research Ltd., a peer-reviewed CDrom teaching resource.

Recent images freely available on the website. Sensitivity/Confidentiality: not confidential but contact data owners.

Study ongoing as described above

See www.niwa.co.nz/services/cam-era/ Additional comments: The Cam-Era project at Tairua and Mokau is a joint project, with costs shared between Environment Waikato and NIWA. Related information: See applications above.