The ocean has been there the whole time. The whole time. I’ve lived within a couple hours of it for years but aside from aquariums and documentaries, I had no way of seeing for myself what actually lived down there. Unlike redwood forests, oak chaparral and alpine lakes, the ocean is a special type of inaccessible even when we’re up to our knees in it. When I got scuba certified with friends not long ago, I finally got to see incredible wildlife in its natural habitat complete with currents, waves, surge, changing weather, shifting sand and everything else that makes an endlessly complicated ecosystem function when it’s not being tended by a navy of aquarium staff.
It is an incredible privilege to experience Monterey Bay in person and it is hard-won. Even after you’ve spent hundreds of dollars on equipment, spent a weekend getting scuba certified and bundled up in thick layers of neoprene to protect you from the bitterly cold water, getting around in the depths is a special challenge.
On a good day in Monterey, visibility might let you see thirty feet in any direction. Though there are more canyons, peaks, columns and arches here than most national parks, there are no sweeping vistas to be had by gazing off into the distance. Every dive is limited to a frustratingly small halo of perception. You can’t swim particularly quickly. You can’t stay particularly long. To satisfy the powerful curiosity that drives us to visit again and again under such conditions sometimes feels like being ravenous in front of a bowl of rice armed only with a pair of tweezers.
On top of that, there are no trails to take you to your destination. Currents and surge may draw you off course and there are few clear landmarks to tell you that you’ve strayed and fewer adequate maps of what’s on the bottom to tell you where they are.
I wanted to make a series of maps that would help amateur explorers plan dives, find the good spots and try new sites with confidence. Enter Avenza Maps. Avenza is a mobile app that users can download to their phones and shop for map products from around the world. Thousands of digital map images can be downloaded and saved locally so that they can be accessed anywhere in the world with or without a mobile data connection. Since GPS does not require a mobile network, a blue marker indicating your location will hover and move across whatever map you’ve downloaded. Think of it as an endless library of Google Map backgrounds where instead of showing your location among shops and buildings downtown they show your position on a National Forest Service map of trails, roads and mountain peaks or a historical city plan from centuries ago. Because I didn’t see any maps specifically for scuba divers that reveal underwater topography, or bathymetry, I decided I needed to make my own.
Recreational scuba diving is intended for shallow water only- maxing out at depths of usually no more than 120 feet for experienced, non technical divers. Waters with rocks, pinnacles, reefs and accessible, shallower water is great for diving but it’s a daunting challenge to map with SONAR devices that are usually mounted on large boats that have to leave plenty of room between rocks that could damage or even sink them. The hundreds of shipwrecks that litter the bottom of the rugged California coastline are a record of how dangerous these shallow waters can be for boats. Stitching together SONAR data from the depths with smaller scale mapping efforts conducted by the Seafloor Mapping Lab at CSU Monterey allowed me to create a rough model of what the bottom looks like almost right up to the beach. For an old-timey aesthetic finishing touch I added nautical charts created by NOAA and satelite imagery to show streets and parking lots. Then I combed through blogs, dive guides and dive shops to come up with a single repository for as many dive sites as I could with as close as I could get to an agreed-upon name. Finally I also added a line representing the 60 foot depth limit suggested for Open Water certified divers and the 120 foot depth limit for Advanced Open Water divers.
Months later, I now have several detailed bathymetric maps of the shallow seafloor just offshore of the most popular dive sites of the Monterey Peninsula. They’re all available for free to download by anyone who has downloaded the Avenza Maps app.
Step 1. Download Avenza Maps from Google Play or the iPhone App Store.
Step 2. Click on the shopping cart and download maps. Mine can be found by either by panning to Monterey or by searching “Bathyscope.” You can download each map individually or you can download the entire bundle of maps at once.
Step 3. Turn on your GPS. When your location is within the extent of the map, you will see your position represented on the map as a blue cursor. Wave your phone around and use the map to see what invisible underwater features you’re pointing at.
Step 4. Plan your dive. Use your compass to get bearings to interesting features that you see on the map and decide which features you’d like to visit. Use the Pin feature to drop bookmarks on specific locations that you’d like to remember like where your sunglasses fell overboard or where your friend says she saw that big lingcod. Add a few notes about the pin on the form.
Step 5. If you recorded a track or you saved some pin locations, you can export them at home into the .kml file format which can be read by Google Earth and most popular mapping platforms. You can keep track and record all of your nautical adventures on your computer.
Step 6. Let me know what you think. I’ve been having fun making these maps and I’d like to make them better. Don’t like the colors or think I’m missing something important? Send me an email or leave a comment here.
There’s a lot of diving in California and I’m excited to try to map all of the best spots along the whole West Coast. I’m currently working on the North Coast of Sonoma, Mendocino and Humboldt but I suspect I’ll go south and pick up popular sites along Big Sur and in Southern California. If you have tips, suggestions or dive spots that I’m forgetting, please let me know.
And as always, have fun and dive safely.