How to use
Enter two or more WGS84 points, or click the map to add points, then read the geodesic distance. Reset when you start a new measurement.
CoordMapLanguage
English
Coordinate input
Point A
LngLat
Click the map or enter WGS84 coordinates
Point B
LngLat
Click the map or enter WGS84 coordinates
Map (MapFirst)
Click the map to pick A then B, or enter WGS84 coordinates and press Enter
Tutorial & notes
How to use
- Map pick — click two locations on the map to mark them and calculate distance
- Enter coordinates — type latitude/longitude, then click Calculate distance
- Sample data — load a quick Beijing–Shanghai example
- Units — results show kilometers, miles, and nautical miles
Distance formula
This tool uses the Haversine formula for great-circle distance on a sphere:
a = sin²(Δφ/2) + cos φ1 ⋅ cos φ2 ⋅ sin²(Δλ/2)
c = 2 ⋅ atan2( √a, √(1−a) )
d = R ⋅ c
Guide, data sources & FAQ
What problem it solves
Computes great-circle style distances for trip planning, radio/line-of-sight estimates and simple GIS checks without desktop GIS software.
Data sources
Distance is calculated client-side on the WGS84 ellipsoid/sphere model used by the tool. Map clicks use the MapLibre basemap (MapFirst).
Frequently asked questions
Is this driving distance?
No. It is geodesic (as-the-crow-flies) distance between coordinates, not road routing.
Which unit is shown?
Results are typically kilometres and metres (and may include miles depending on the UI). Convert as needed for your workflow.
Can I measure multi-leg paths?
Add multiple points to sum segment distances when the tool supports a point list or click path.
Do I need a geocoder?
Not for pure distance. Geocode addresses first if you only have place names.