# Measures of the model change after I run GPA+PCA

**URL:** <https://discourse.slicer.org/t/measures-of-the-model-change-after-i-run-gpa-pca/36797>\
**Category:** Support\
**Created:** [June 15, 2024, 3:37am UTC](https://discourse.slicer.org/t/measures-of-the-model-change-after-i-run-gpa-pca/36797 "2024-06-15T03:37:12Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![Dani98](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/dani98/32/67536_2.png) [@Dani98](https://discourse.slicer.org/u/Dani98)\
**Post date:** [June 15, 2024, 3:37am UTC](https://discourse.slicer.org/t/measures-of-the-model-change-after-i-run-gpa-pca/36797/1 "2024-06-15T03:37:12Z")

</div>

I have a problem with the module GPA+PCA  
I have to create a statistical model but when I run the module GPA+CPA the measures of my models change and in particular there is a reduction of these measures  
I don’t understand the reason because before the running of GPA+PCA the measures are correct…what can I do?  
Thank you!

---

<div class="post-metadata">

**Author:** ![muratmaga](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/muratmaga/32/3622_2.png) [@muratmaga](https://discourse.slicer.org/u/muratmaga)\
**Post date:** [June 15, 2024, 3:53am UTC](https://discourse.slicer.org/t/measures-of-the-model-change-after-i-run-gpa-pca/36797/2 "2024-06-15T03:53:57Z")

</div>

> [@Dani98](#):
>
> the measures of my models change and in particular there is a reduction of these measures

By measures do you mean the scale of the landmarks change? That’s expected because Generalized Procrustes Analysis (GPA) requires the coordinates to be scaled by centroid size. If you want to preserve the scale of your data, make sure to check the “Enable Boas Coordinates” option before executing the GPA.

This will still conduct the GPA alignment in unit coordinates, but put the scale back after the superimposition is completed. Your PCA decomposition will then be conducted on properly scaled data.

---

<div class="post-metadata">

**Author:** ![Dani98](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/dani98/32/67536_2.png) [@Dani98](https://discourse.slicer.org/u/Dani98)\
**Post date:** [June 15, 2024, 8:57am UTC](https://discourse.slicer.org/t/measures-of-the-model-change-after-i-run-gpa-pca/36797/3 "2024-06-15T08:57:04Z")

</div>

Thank you very much!  
I have another question…I created a cut plane through the module “reformat” and I cut my model in the section “models” by using clipping  
But now after the cut, I do not know how to remove the plane as it remains visible…how can I do this?

---

<div class="post-metadata">

**Author:** ![muratmaga](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/muratmaga/32/3622_2.png) [@muratmaga](https://discourse.slicer.org/u/muratmaga)\
**Post date:** [June 15, 2024, 3:30pm UTC](https://discourse.slicer.org/t/measures-of-the-model-change-after-i-run-gpa-pca/36797/4 "2024-06-15T15:30:03Z")

</div>

You can control the visibility of the Markups (planes, ROIs, points, lines etc) by turning off/on the eye icon in the Data or Markups modules.