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Turf distance measurement doesn't match TurfJS

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Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
48/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
java, javascript
Domain
backend

Research direction

Start with services-turf/src/main/java/com/mapbox/turf/TurfMeasurement.java and compare its distance calculation with TurfJS, then inspect services-turf/src/test/java/com/mapbox/turf/TurfMeasurementTest.java. Determine why the implementations produce different values and update the implementation or expectations so the distance test reflects the intended TurfJS behavior.

Written by the indexing model from the issue text.

Description

question Turf

I am trying to port transformRotate from Turf.JS as I need it for a project.

In the method comments there are some examples with the expected result, my port didn't match. In trying to debug this I've noticed that the distance tests don't match between JS and the Java port.

The standard test points [-75.343,39.984][-75.534, 39.123] used the km distance in TurfJS is 97.12922118967835

Those same points are tested in the port but the expected result is different: 97.15957803131901

This third party suggests TurfJS is correct.

I've noticed Earth radius is different between the implementations so I guess this is the why

6371008.8

6378137

I see JS nearly changed to the same value for earth's radius but got reverted.

Is there a reason the port doesn't produce the same result as the original?

Dominant language
Java
Stars
438
Forks
117
PR merge metrics
No merged PRs in 30d

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