geoprimsField-grade geospatial math

Waypoints along a route line

Points along the geodesic (or rhumb line) from A to B at N equal intervals, a fixed spacing, or given fractions, with distance and course at each, as a table, a route, and GeoJSON.

Planning and education aid. Not for primary navigation. Full disclaimer

11

There are 11 points along the 5,554.909 km line.

Points
PointLatitudeLongitudeDistance from the startCourse here
140.6413000 deg-73.7781000 deg0.000 km51.382 deg
243.6405668 deg-68.3980904 deg555.491 km54.994 deg
346.3595958 deg-62.4828931 deg1,110.982 km59.180 deg
448.7409796 deg-55.9912413 deg1,666.473 km63.973 deg
550.7217094 deg-48.9136096 deg2,221.964 km69.377 deg
652.2375218 deg-41.2903387 deg2,777.454 km75.346 deg
753.2300588 deg-33.2262221 deg3,332.945 km81.767 deg
853.6559284 deg-24.8920619 deg3,888.436 km88.466 deg
953.4950914 deg-16.5056534 deg4,443.927 km95.218 deg
1052.7552218 deg-8.2944801 deg4,999.418 km101.791 deg
1151.4700000 deg-0.4543000 deg5,554.909 km107.983 deg
Line length
GPX route
GeoJSON
Provenance
Computed by
navigation.geodesic.waypoints 1.0.1, core 0.1.0
Model
Karney (2013) geodesic on WGS 84
Accuracy
Points on the geodesic to nanometers
Notes
None
Cites
Karney, C. F. F., Journal of Geodesy, Algorithms for geodesics

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How we got thisFormula, worked example, sources, and proof

Model: Karney (2013) geodesic on WGS 84

Accuracy: Points on the geodesic to nanometers

When to use this: Use this to lay points along a route: evenly spaced marks for a flight log, a track to draw on a map, a line to sample terrain or weather along, or a GPX or GeoJSON file to load somewhere else. The points sit on the geodesic, which is the line the route actually follows.

Limitations: The points are on the shortest path, so drawn on a Mercator chart they curve; a line that holds one heading is the rhumb tool instead. Spacing is even in distance along the line, not in latitude or longitude, and not in time unless the speed is constant. Between two nearly antipodal points the shortest path is poorly determined, so a small change in either end can swing the whole line to the other side of the globe.

Worked example: JFK to London Heathrow in 10 equal intervals. Source: navigation geodesic scenario: 11 points, each 555,490.879 m apart along the geodesic.

You enter

Equal intervals
10
Start latitude
40.6413 deg
End latitude
51.47 deg
Start longitude
-73.7781 deg
End longitude
-0.4543 deg

You get

Points
11
Line length
5,554.909 km
GPX route
<?xml version="1.0" encoding="UTF-8"?> <gpx version="1.1" creator="geoprims" xmlns="http://www.topografix.com/GPX/1/1"> <rte> <rtept lat="40.6413" lon="-73.7781"><name>WP1</name></rtept> <rtept lat="43.64056679524166" lon="-68.39809036393899"><name>WP2</name></rtept> <rtept lat="46.3595958442832" lon="-62.48289308098586"><name>WP3</name></rtept> <rtept lat="48.7409796110797" lon="-55.99124127026883"><name>WP4</name></rtept> <rtept lat="50.72170942137994" lon="-48.91360956372871"><name>WP5</name></rtept> <rtept lat="52.23752180221283" lon="-41.290338700015006"><name>WP6</name></rtept> <rtept lat="53.23005879760413" lon="-33.22622207839571"><name>WP7</name></rtept> <rtept lat="53.65592838760919" lon="-24.89206188943215"><name>WP8</name></rtept> <rtept lat="53.49509142647097" lon="-16.5056534335194"><name>WP9</name></rtept> <rtept lat="52.755221792887866" lon="-8.29448013061733"><name>WP10</name></rtept> <rtept lat="51.470000000000006" lon="-0.4543000000000035"><name>WP11</name></rtept> </rte> </gpx>
GeoJSON
{"type":"Feature","properties":{},"geometry":{"type":"LineString","coordinates":[[-73.7781,40.6413],[-68.39809036393899,43.64056679524166],[-62.48289308098586,46.3595958442832],[-55.99124127026883,48.7409796110797],[-48.91360956372871,50.72170942137994],[-41.290338700015006,52.23752180221283],[-33.22622207839571,53.23005879760413],[-24.89206188943215,53.65592838760919],[-16.5056534335194,53.49509142647097],[-8.29448013061733,52.755221792887866],[-0.4543000000000035,51.470000000000006]]}}

Review: Not yet independently reviewed by a geodesist.

Last verified: 2026-09-18, when a maintainer last confirmed this tool's sources at the issuer. See the sources ledger.

Status: version 1.0.1, core 0.1.0. See this tool in the verification report.

Changes

Checked against: 22 golden test vectors (download the test vectors, each with its source and tolerance). See how results are checked and every source.

Sources

Terms

GPX: GPS Exchange Format
An XML file format for waypoints, routes, and tracks that most GPS devices and mapping apps read. Source: GPX: the GPS Exchange Format

GPX — GPS Exchange Format

An XML file format for waypoints, routes, and tracks that most GPS devices and mapping apps read.

Source: GPX: the GPS Exchange Format