mccabejc
Contributor
I want to make a topographical map of a set of reefs, which are pretty much an extension of a local beach. If that's too much to accomplish, then at least I'd like to be able to draw an outline of the reefs without depth/topo information. I'm trying to figure out the cheapest and best way to do it. I'd like to do it at 0 cost, of course, and might pay some money on equipment only if I can use for other things.
I'm looking for some thoughts on ways to accomplish this. Here's what I've considered so far:
1. Accessed the Terraserver (http://terraserver.microsoft.com/) to find satellite images of the beach, hoping to see an aerial view of the reefs with sufficient definition to define the outline of the reef. Found the exact image I needed, but unfortunately, it didn't have quite enough definition. I guess conditions have to be just right. In any case, here's the photo if anyone is interested. It's the reefs surrounding the splotch of white at the bottom center of the image, where waves are breaking on some parts of the reef:
http://terraserver.microsoft.com/image.aspx?t=1&s=10&x=2130&y=18559&z=11&w=1
2. Also considered using sonar, but that's too big a production. Side scan sonar would be neat, but mine's in the shop.
3. I just ordered a handheld depth finder (http://www.vexilar.com/products/lps1.html) which is just a neat dive gadget, and I could probably use it to provide depth info as I paddled around the reef in a kayak or something. I was also thinking of correlating that info with GPS location waypoints from cheap handheld GPS, which might ultimately allow me to plot out depths and generate a topo on the aforementioned terraserver image if I did things right. Still seems like a lot of work to me. And if I was to go really nuts about this, I could enter the data into my 3D animation software and generate a 3D image of the reef that you can rotate and stuff. Cool....
4. I could wait for the perfect visibility and lighting conditions (whatever that may be), and find a spot on the cliff which rises maybe 30 or so feet above the beach and take a photo of the reef. That would at least give me an outline. But my guess is that the sun would have to be directly overhead or behind me, which means sometime in mid-summer, because now the sun would be low on the horizon in front of me.
5. I could ask a diver who is also pilot to fly over the reef when conditions are perfect and take a photo.
6. All of the equipment which involves towing a GPS device around on a float above you as you measure depth is way too much hassle, and too expensive.
7. It would be ideal if there were existing topo maps which extended past these reefs, but I'm not aware of any. Anyone know of any marine topo maps I can access for this area?
You may ask why I want to do this. Well, because I've dove this reef a couple of times and cannot figure out how it's laid out. There is a map in one of our local dive books (http://www.saintbrendan.com/cdnjuly02/Fishermans.html) which I couldn't seem to correlate to the actual reef. My next step is to ask the author how they came up with the map.
Thanks for any input.
I'm looking for some thoughts on ways to accomplish this. Here's what I've considered so far:
1. Accessed the Terraserver (http://terraserver.microsoft.com/) to find satellite images of the beach, hoping to see an aerial view of the reefs with sufficient definition to define the outline of the reef. Found the exact image I needed, but unfortunately, it didn't have quite enough definition. I guess conditions have to be just right. In any case, here's the photo if anyone is interested. It's the reefs surrounding the splotch of white at the bottom center of the image, where waves are breaking on some parts of the reef:
http://terraserver.microsoft.com/image.aspx?t=1&s=10&x=2130&y=18559&z=11&w=1
2. Also considered using sonar, but that's too big a production. Side scan sonar would be neat, but mine's in the shop.
3. I just ordered a handheld depth finder (http://www.vexilar.com/products/lps1.html) which is just a neat dive gadget, and I could probably use it to provide depth info as I paddled around the reef in a kayak or something. I was also thinking of correlating that info with GPS location waypoints from cheap handheld GPS, which might ultimately allow me to plot out depths and generate a topo on the aforementioned terraserver image if I did things right. Still seems like a lot of work to me. And if I was to go really nuts about this, I could enter the data into my 3D animation software and generate a 3D image of the reef that you can rotate and stuff. Cool....
4. I could wait for the perfect visibility and lighting conditions (whatever that may be), and find a spot on the cliff which rises maybe 30 or so feet above the beach and take a photo of the reef. That would at least give me an outline. But my guess is that the sun would have to be directly overhead or behind me, which means sometime in mid-summer, because now the sun would be low on the horizon in front of me.
5. I could ask a diver who is also pilot to fly over the reef when conditions are perfect and take a photo.
6. All of the equipment which involves towing a GPS device around on a float above you as you measure depth is way too much hassle, and too expensive.
7. It would be ideal if there were existing topo maps which extended past these reefs, but I'm not aware of any. Anyone know of any marine topo maps I can access for this area?
You may ask why I want to do this. Well, because I've dove this reef a couple of times and cannot figure out how it's laid out. There is a map in one of our local dive books (http://www.saintbrendan.com/cdnjuly02/Fishermans.html) which I couldn't seem to correlate to the actual reef. My next step is to ask the author how they came up with the map.
Thanks for any input.
