Sailing with Google Earth for Navigation

What a wonderful holiday in the Virgin Islands! I took my family down to charter a sailing catamaran very similar to the one we owned four years ago (read more). We chartered a Voyage 440 catamaran (44 feet in length, 25 feet wide) from Voyage Charters out of Soper’s Hole Marina, on the west end of Tortola, British Virgin Islands. Voyage has nearly 50 well-maintained catamarans for charter – either bareboat or with a crew. Within a few days I will be posting geo-tagged photos, GPS tracks, and a Google Earth visualization showing more details about our trip.
As mentioned before I left, I planned to take some Google Earth technology to experiment with while I was on the trip. (Yes, I’m a geek, so I love to play with gadgets even on a vacation.) This article will summarize my experiences with those technologies. Specifically, I wanted to test the ability to use Google Earth as a navigational tool while under sail. I brought the following tools:

1. Windows Laptop – some of the tools I used were only available for Windows.
2. Google Earth – just the basic free version
3. GPS – used a Garmin 60Cx – a nicely featured GPS with color screen and charts. But, a basic Garmin GPS with a serial or USB port would have worked just as well.
4. EarthNC – EarthNC offers very nicely converted digital vector nautical charts for Google Earth (KML format) from the US National Oceanic and Atmospheric Administration (NOAA) – over 600 charts. The EarthNC charts take very good advantage of advanced KML features to present colorful information for the charts (depth contours, buoys, hazrds, etc.) in an eye-pleasing and informative fashion in Google Earth. See my earlier review of EarthNC.
5. GooPs – GooPs provides tools for linking your GPS with Google Earth and drives your view in GE so you can use it for navigation. Even the Pro version only costs US$14.95
6. Franson’s GPSGate – I needed this in order to allow GooPs to think I had my GPS hooked up by serial port instead of the USB. I’m told GooPs will soon have its own ability to handle USB GPS interfaces. I used the 14-day trial version for GPSGate for my review. It worked perfectly.

Thanks to an update to the Google Earth base imagery for the Virgin Islands (coincidentally at the beginning of my trip – thanks guys!), Google Earth had great views of my intended anchorages.
So, while I was sailing about, I had my GPS running all the time recording my tracks. I also occasionally hooked up the GPS to the laptop and fired up the applications above. It was amazing to watch my current position in the 3D Google Earth, with EarthNC’s nautical charts overlayed to give me an idea of my nautical surroundings. I had no Internet connection while I was offshore, but I had cached the imagery and terrain for the areas I was intending to sail before I left the marina. Before leaving home, I made sure to have interesting placemarks of the places I wanted to visit already in my My Places folder. And I installed GooPs (very simple), EarthNC and GPSgate and tested them.
An Internet connection while we were sailing would have enabled me to add real-time satellite and other weather overlays, check out Panoramio photos, show my position in real-time, etc. But, Internet access away from shore is not an easy thing to accomplish – especially with broadband. Satellite solutions are either prohibitively expensive, or too slow for GE’s high bandwidth demands. But, I had radio communications for weather forecasts. And the cache works great for most needs.
The whole setup worked very well indeed! GooPs and EarthNC have not yet evolved GE into full-fledged sailing navigation software systems. But, the experience was still better in many ways than real marine systems which cost thousands of dollars. I couldn’t easily make the screen show critical sailing information such as heading, speed, course in large enough letters to view from a distance. Also, the system isn’t set up to synchronize with data from other instruments on the boat for wind speed, boat speed, wind direction, etc. Since there are many boat instrument manufacturers and protocols, writing interfaces is not a little project. Adding these capabilities would make it more possible to really navigate with these tools. If EarthNC offered KML for other nautical chart data sources then world-wide coverage would be possible.
The vector nautical chart for the British Virgin Islands from NOAA appears to have a projection problem. This meant that the chart data from EarthNC was slightly offset – mostly for the north-eastern part of the BVIs. Virgil was aware of the issue and has contacted NOAA. The US Virgin Islands charts were quite accurate though. While traveling near St. John, I was able to watch my position in Google Earth with very well-aligned nautical charts (see the screenshot above). I found it most useful to have my view tilted about about 50 degrees in GE and use the “Rotate” mode of GooPs to always show my view in the direction the boat was traveling. This was really wild to watch when we would tack or jibe the boat (change directions). The vector chart data combined with the Google Earth imagery gave me much better awareness than the expensive professional chart plotters I used in my previous boat four years ago.
I did not use this set up as my primary means of navigating the boat. You use your eyes, paper charts, and sea skills primarily in these waters. But, for planning purposes and for verification of our position while under way, this was a real pleasure to use. For a minimal investment, and if you are a big Google Earth enthusiast, you could easily use this set up to impress your boating friends. Don’t forget, the same setup could be used for any land-based activity, or even in an airplane as well! If you have an Internet connection, you can subscribe to a Franson GPSGate server to upload your position and people can watch your position in real-time – with Google Earth and GooPs and/or EarthNC (if you’re on the water).
I would like to thank both the makers of GooPs and EarthNC for giving me copies of their software and data for the review.

About Frank Taylor

Frank Taylor started the Google Earth Blog in July, 2005 shortly after Google Earth was first released. He has worked with 3D computer graphics and VR for many years and was very impressed with this exciting product. Frank completed a 5.5 year circumnavigation of the earth by sailboat in June 2015 which you can read about at Tahina Expedition, and is a licensed pilot, backpacker, diver, and photographer.

• More Posts(1963)