Mapping dive sites can be a challenging but rewarding experience, and is a good way to expand your own navigation skills. It is also a great way to “re-explore” dive sites that you may have been to over and over again. Good quality maps of dive sites are highly useful tools and if you have a lot of experience with a particular dive site, you can pass that knowledge onto newer divers who will use it to get the most out of their dives, and if you are a Divemaster or Instructor then they can be used during your dive briefings.
How to make a dive site map
To create a good quality dive site map you actually need very few pieces of equipment, in fact everything you need is standard equipment so if you have a full set of scuba equipment you don’t need to buy anything else. You will need a (preferably large) blank slate with a pencil, an accurate depth measuring device such as a dive computer, an accurate compass and a buddy. Having a tape measure (30m) is nice to have, although not a requirement. It will help make the map more accurate than if you were measuring using kick cycles or elapsed time. The reason why you are mapping would dictate the accuracy the map needs. For instance a scientific dive site map would need accurate measurements, but for use in dive briefings measuring using kick cycles would be fine.
The first step
The first step in drawing a map would be to set up a center point that you would start from. The best way to do this is to have a surface marker such as a buoy or an SMB which is attached to the dive site. If the site is shallow or the visibility is good then you would want to first snorkel over the site to get the basic outline. It is important not to just swim randomly about. You should use a search pattern such as an expanding square or a U pattern. If snorkeling is an option then you may be able to draw out the basic shape of the site before even going for a dive. This will make filling in the details much easier later on. If snorkeling is not an option then you should spend at least one dive just getting the outline planned. If this is a deep dive site then make sure you regularly check your air supply and no decompression limit (NDL) as it is easy to forget when you are focused on something else.
When it is time to fill in the details you will need to spend at least one dive, preferably more (depending of site size) filling in all the details. This could be certain coral species that may live there, or points of interests such as a sunken boat, or even a certain aquatic animal that spends most of its time in one specific place, such as an octopus, stingray or a school of fish that doesn’t move around. You will need to note the bottom compositions as you will need to label them on the final map. You also need to gather all the depths around the site, and also the depths along the top of the reef. If you find there a lot of variation in the depths then it is even more to note the depths, so divers who use your map will be able to tell exactly where they are from the depths noted.
The final product
Once you are happy with your map then it is time to draw it up properly. There are two ways to do this, the first is to draw it up by hand. For this you will ideally use graph paper, a pencil and a protractor (to measure angles properly). If you are mapping a tropic coral reef then it is nice to use colored pencils to show specific species of corals, and write a key so divers can know what the different colors mean. If you are fairly good with a computer you can draw one using a program such as Adobe Illustrator. This will make the finished map look much tidier than if draw on paper. This also gives the advantage of being able to make a layer that follows your search pattern so you can draw the map more accurately, and after the map is complete you can hide or delete the search pattern layer. With computers you can also load the map online once completed so not only divers you come into contact with can use your map, everyone can find it!
Dive mapping has been a key focus of many diving areas recently. On the island of Koh Tao in Thailand you can buy a dive guide that has maps of almost all the dive sites around the island. In the Caribbean there are many professionally made maps available online and on the Great Barrier Reef in Queensland, Australia you can even use Google Street View to complete a dive before you even get wet! I have no doubt that as diving becomes even more popular than it is, and with the ease of access to information from the internet, it won’t be long until you can find almost any accurate dive map online. Maybe one day dive computers may have built in GPS which allows you download maps of any dive site so you will never get lost on a dive again!
‘Mapping Dive Sites’ was written by Mike
Photo Credit: www.michaelmcfadyenscuba.info