# Question about the minor and major axes' length formulas

**URL:** <https://discourse.slicer.org/t/question-about-the-minor-and-major-axes-length-formulas/39713>\
**Category:** Support\
**Created:** [October 15, 2024, 7:24pm UTC](https://discourse.slicer.org/t/question-about-the-minor-and-major-axes-length-formulas/39713 "2024-10-15T19:24:11Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Steven](https://avatars.discourse-cdn.com/v4/letter/s/94ad74/32.png) [@Steven](https://discourse.slicer.org/u/Steven)\
**Post date:** [October 15, 2024, 7:24pm UTC](https://discourse.slicer.org/t/question-about-the-minor-and-major-axes-length-formulas/39713/1 "2024-10-15T19:24:11Z")

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Hello, I have a question about the elliptical features minor and major axes’ length. The formulas given in the Pyradiomics documentation are respectively 4_sqrt(lambda\_major) and 4_sqrt(lambda\_minor), with lambda\_major and lambda\_minor being the largest and smallest principal components of the physical coordinates of the pixels to which the ellipse is fitted. I was wondering if a demonstration of these formulae was available somewhere as I did not manage to find it. Thanks in advance!