Hierdie persoon kan bydraes maak met gemiddelde Afrikaans.
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User:Pbsouthwood no longer comtributes to Wikitravel, but you can still contact me by email • • • Peter (Southwood)Talk 02:08, 21 August 2012 (EDT)
I am surveying and mapping the dive sites of Cape Town as a long term project. Wikitravel was how I made this information available to the public on a constantly updated format.
Most of the surveys are done by towing a surface marker buoy on a tight tether along a chosen contour, then after the dive I download the GPS track and transfer it to Inkscape and trace around it to show the shape of the site. A similar process is used for the outlines of reefs and wrecks, and some details are simply measured and sketched on site. On rare occasions the visibility is good enough to use photos and video to provide details.
Since March 2011 I have had access to unpublished data from the SA Council for Geoscience which did a sidescan sonar survey and fascies interpretation of parts of False Bay and the Atlantic seaboard of the Cape Peninsula for a reef ecology monitoring project. This data lacks detail of depth and can be difficult to interpret with precision, but it is excellent for identifying roughly where all the rocky areas are. However it is limited to places where the sonar fish is not likely to hit rocks, so there is still plenty of reef that has to be identified and mapped in other ways in the close inshore zone, Also it does not give depth profiles. The main value is that it is possible to be reasonably sure that most reef has been identified in these zones.
Most of the boat access sites were mapped from Blue Flash charters boats, as Blue Flash caters largely for a fairly regular clientele of advanced local divers, and is more inclined towards exploring new areas and opening up new sites, and a moderate number from Dive and Adventure and Pisces Diving boats. The owners support this project by allowing me a special rate for boat dives. The shore dives were done under my own power, usually alone, but sometimes with a few buddies who are prepared to swim along with me while I survey.
I would welcome participation from other local divers, but so far I have been unable to persuade any of them to actually go out and survey.