A new method of navigation for this summer…

Purple vs. White: More Accurate Wind Maps

When you are heading out on the water, you want the most accurate forecast possible for wind and sea state. All other apps and weather services use the same antiquated GRIB weather. But that is based on low-res imaging from satellites 500 – 22,000 miles up in space. Here is a quick summary of modern wind maps as shown in the animation above, which is now available in the SailTimer app and soon also in other partner apps.

Our crowdsourced wind measurements from users (purple lines) have 20-meter resolution. As you zoom in on the map you can see more and more detail. These are accurate because they are based on actual wind measurements.

The GRIB cells (white lines) have low resolution with cells that are 7.5 x 7.5 nautical miles or larger. The wind is supposed to be the same everywhere within that huge area. They have poor accuracy because they are based primarily on satellite imaging. We tested the accuracy of the GRIB wind forecasts with 103,000 measurements on ships in this research report published in ECO Magazine: Environment, Coastal & Offshore). Here is the conclusion:

…The GRIB satellite forecast is shockingly inaccurate when compared to measurements… The mean absolute error in forecasted wind directions is +/-35.4 degrees (a range of 70 degrees!).

In the example shown above, the white lines are all forecasting wind from the North West. The purple lines have higher resolution based on actual wind measurements, and show different wind directions in some places. The GRIB forecast is too coarse for use in coastal areas and for vessels entering harbors.

Crowdsourced measurements solve this problem. Our wind models in coastal areas currently have over 111-million data points from users worldwide.

This new visualization is the first-ever wind map that shows GRIB data with low resolution and crowdsourced data with high resolution. 

DIY Wind Maps

The beauty of crowdsourcing is that you can generate these kinds of accurate, high-res wind maps for your own location, or contribute more data. That gives you reliable data for planning your route. And from home you can use maps like the one above to check wind conditions at your boat.

Marine weather and navigation is being transformed. For the first time in the history of seafaring, you can use a wind sensor on your boat for local wind, and crowdsourced wind maps to see wind conditions around the next point, out on the open water, or funneling into a harbor.

Using this technology is easy. You can use the SailTimer app to view purple vs. white wind maps like the one above (and soon other partner apps as well; stay tuned). You can share your wind measurements using our wireless Wind Instrument ($349.99) or our Ultrasonic wind sensor ($299.99). Or you can use our $75 Air Link™ with any type or brand of wind sensor.