So in pursuit of creating the map, I looked up GIS software and of course the daddy of it all is the US Geological Survey's The National Map page for downloading pre-existing maps and The National Map Viewer for creating custom maps. I'll admit, after taking up 15 of the 30 minutes max I wanted to spend on this little project just exploring the features and lingo of these tools, I decided that the USGS NM and NMV were more high tech and less user friendly than I wanted. So I went looking for an easier user interface (note, I didn't say better)...
And I found the National Geographic MapMaker Interactive tool which allowed me to do everything I wanted, like draw on the map, zoom in, choose a satellite version (vs. topographic or street map) of the island, everything I was looking for initially... except download an image ( you could download a pdf, which I suppose could be converted to an image, etc, etc. but I wanted it now! Thank you, MS Windows, for the PrtSc function but then I needed to crop out the window, so my "workaround" still involved work.)
Here's the route my friends take for one of their snorkeling trips:
After I created that map, I then got all excited to see where all the coral reefs are located around Vieques Island and found the excellent tool ReefGIS by ReefBase, which is a database used by several international coral monitoring networks with funding by the United Nations Foundation. Below is a map displaying corals by their depth.
Light purple is shallow reefs, mid purple is mixed shallow/deep reefs, and dark purple is deep reef. Unfortunately, the actual depths were not included in the map, but from my snorkeling experience, I can say the mixed depth reef ranged from 8 - 20 feet deep. After checking the National Oceanic and Atmospheric Administration's (NOAA) Coral Reef Conservation Program page, I learned that corals may grow to depths of over 200 ft and that shallow reefs may be considered up to 90 feet in depth. Wow! But then that makes me want to question the map's data and what ranges were set. Oh, well, at least it identifies location of corals around Vieques. Enjoy.