[Coral-List] Photoquadrat

[Chris Lapointe]

Ron,

It should not be a problem switching cameras as long as you analyze the same
area. If you are using a wider angle lens, then all you would have to do is
isolate the area within the photoquadrat in CPCe to be the same area as
previous images before overlaying points. The only difference then would be
the change in megapixels, if the new camera has higher resolution. I use a
10 megapixel camera when doing coral surveys which allows for easier
identification if you need to zoom into the image.  You said that you are at
sites with some turbidity, so any increase in resolution will only help.

I hope that this helps.

Chris Lapointe
Research Assistant
National Coral Reef Institute
Oceanographic Center
Nova Southeastern University
8000 N. Ocean Drive
Dania Beach, FL. 33004



On Tue, Jun 30, 2009 at 9:29 PM, Ron Kirby Manit <rk.manit at gmail.com> wrote:

> Project Seahorse Foundation for Marine Conservation
> 30 June 2009
>
> Methodological Question about Photoquadrats for “Coral List”
>
> The benthic survey component of our coral reef long-term monitoring program
> has (again) presented us with some tricky methodological issues, and were
> hoping to consult with this community for advice on how to resolve them. We
> are a small marine conservation NGO conducting research on marine protected
> areas in the central Philippines, with a small team of marine biologists.
>
> Some background: we piloted a photoquadrat (“PQ”) method in 2007 to replace
> our older line-intercept method. At each survey site, this PQ method uses
> 10
> haphazardly laid 25 m transects, with photos taken every 1 m along the
> transect. We plan to conduct PQ once a year at these sites, all of which
> are
> shallow (~3-4 m depth) with some turbidity.
>
> Basically, our current digital camera (Sony DSC-P10 Cybershot, 5.0
> megapixels, purchased in 2003) has been malfunctioning and we need to
> replace it. We are very concerned that if we simply bought a new camera
> (with new wide-angle lens etc.) that the photodata we have already gathered
> using this old camera would not be comparable with the newer photodata with
> whatever new camera equipment we decide to purchase. Our current wide angle
> lens is the “MPK-P9 wide version 16 mm/F5.6.” We use CPCE to process the
> images.
>
> Are photoquadrat methods using this image-processing software sensitive to
> the exact specifications of particular cameras? Or is the software and
> analysis of this kind of data robust to all kinds of equipment? What kind
> of
> considerations do we need to keep in mind when making this decision? Would
> it be ok if just replace our camera with a new set of camera that are of
> different specs on the camera that we are using?
>
> We would appreciate any advice this community can offer. Thanks!
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