# Pygplate bug for intersection on sphere

**URL:** https://discourse.gplates.org/t/pygplate-bug-for-intersection-on-sphere/102
**Category:** Q&A
**Created:** [22 March 2020 17:13 UTC](https://discourse.gplates.org/t/pygplate-bug-for-intersection-on-sphere/102 "2020-03-22T17:13:21Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![bruce.eglington](https://discourse.gplates.org/letter_avatar_proxy/v4/letter/b/2acd7d/32.png) [@bruce.eglington](https://discourse.gplates.org/u/bruce.eglington)
#### Post date: [22 March 2020 17:13 UTC](https://discourse.gplates.org/t/pygplate-bug-for-intersection-on-sphere/102/1 "2020-03-22T17:13:21Z")

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There seems to be a bug in the routine to calculate intersection on a sphere in pygplates. The bug only occurs on the equator and at negative longitudes. I have emailed a test case directly to John Cannon.

Regards  
Bruce Eglington

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### Author: ![john.cannon](https://discourse.gplates.org/letter_avatar_proxy/v4/letter/j/3e96dc/32.png) [@john.cannon](https://discourse.gplates.org/u/john.cannon)
#### Post date: [1 April 2020 12:01 UTC](https://discourse.gplates.org/t/pygplate-bug-for-intersection-on-sphere/102/2 "2020-04-01T12:01:06Z")

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Thanks for the test case! It revealed a couple of bugs which are now fixed, and will be in the next public pyGPlates release (sometime in H2 of this year, hopefully early in H2).

Regards,  
John