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THE FEUTEX TOOLKIT

Great-Circle Distance

Measure the shortest spherical surface route and straight chord between two latitude-longitude positions.

Geometry workspace● Runs in your browser
01 Your input
02 Your result
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FormulaCentral Angle = 2*asin(sqrt(max(0,min(1,sin((lat2-lat1)*PI/360)**2+cos(lat1*PI/180)*cos(lat2*PI/180)*sin((lon2-lon1)*PI/360)**2)))); Surface Distance = r*(2*asin(sqrt(max(0,min(1,sin((lat2-lat1)*PI/360)**2+cos(lat1*PI/180)*cos(lat2*PI/180)*sin((lon2-lon1)*PI/360)**2))))); Chord Distance = 2*r*sin((2*asin(sqrt(max(0,min(1,sin((lat2-lat1)*PI/360)**2+cos(lat1*PI/180)*cos(lat2*PI/180)*sin((lon2-lon1)*PI/360)**2)))))/2)
Sources and model references

Worked example

Inputs

First latitude
0 degrees
First longitude
0 degrees
Second latitude
0 degrees
Second longitude
90 degrees
Sphere radius
6371 km

Expected results

Central Angle
1.570796327 rad
Surface Distance
10007.5434 km
Chord Distance
9009.954606 km

Load the example in the workspace to reproduce these results. Display rounding does not change the underlying calculation.

How to use this tool

  1. Enter the labeled inputs using consistent units.
  2. Check the stated assumptions and calculate.
  3. Review each output and compare another input scenario.

Try this example

{
  "lat1": 0,
  "lon1": 0,
  "lat2": 0,
  "lon2": 90,
  "r": 6371
}

Accuracy and scope

Spherical approximation with user-selected radius; not an ellipsoidal surveying calculation. Finite floating-point arithmetic; results can lose precision near singular or extreme inputs.

Is my data uploaded?

This tool runs locally in your browser. Input and output are not sent to a processing server. Copy or download your result before leaving the page.