First, pick which circle you are interested in below. Then, just zoom, grab, and move the map until the crosshair is exactly over your operating position and see your latitude, longitude, and distance from the center of the selected circle.
You can use the Google search tool in the bottom left corner of the map to enter your address and quickly jump there.
IMPORTANT: Near the edge of the circle, use the calculated value below, NOT the blue edge of the circle. The circle is drawn at a small scale and when you zoom in, it's not as accurate as the calculated value below.
Written by David Spoelstra, N9KT. Please email me any suggestions for changes!
Latitude, Longitude:
Miles from circle center:
You are miles the circle.
In 1975, Thaddeus Vincenty devised a formula for calculating distances between a pair of points on the earth's surface using an accurate ellipsoidal model of the earth.Vincenty's formula is accurate to within 0.5mm, or 0.0000153", on the ellipsoid being used. Calculations based on a spherical model, such as the much simpler Haversine, are accurate to around 0.3%.
The most accurate and widely used model for the earth's ellipsoid is WGS-84.The United States,and this script,use GRS-80 which is functionally equivalent to the WGS-84 ellipsoid but more accurate for our area.