How can I compute the distance from a buoy to shore, an inlet, or another reference location?

Often, when you ask us how far a buoy is away from a location, we don't know the exact location of the jetty, inlet, or the point on shore that you are referring to. We'd hate to guess and give you the wrong information. However, it's fairly easy to determine this yourself if you can find the latitude and longitude of your reference position.

Copy the station's latitude and longitude from the station page. Next, look up the latitude and longitude of the inlet, lighthouse, town, or other geographic feature you are interested in. You can find these on NOAA nautical charts: http://anchor.ncd.noaa.gov/noaa/noaa.html provides a listing of these charts which you can purchase. Sometimes, you can find the location of a point on shore through the U.S. Census TIGER map server.

When you have this information, do an Internet search for a "Great Circle Calculator" and go to one of the web sites featuring this type of calculator.

Here's a Great Circle Calculator offered by the U.S. Dept. of Agriculture: http://www.wcrl.ars.usda.gov/cec/java/lat-long.htm.

Here's another one from an international non-profit organization, the World Air Sports Federation: http://www.fai.org/distance_calculation/.

Finally, one from the Kansas City Amateur Radio Club: http://www.kcatv.org/gccalc.htm.

Then, enter the latitude and longitude of our buoy and the position of your reference location. The calculator will give you the distance in several units and a bearing.