# Fiducials in Slicer-4.11. / 4.10 "R" and "A" flipped coordinates?

**URL:** <https://discourse.slicer.org/t/fiducials-in-slicer-4-11-4-10-r-and-a-flipped-coordinates/22342>\
**Category:** Support\
**Created:** [March 7, 2022, 9:39am UTC](https://discourse.slicer.org/t/fiducials-in-slicer-4-11-4-10-r-and-a-flipped-coordinates/22342 "2022-03-07T09:39:53Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![CST](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/cst/32/6502_2.png) [@CST](https://discourse.slicer.org/u/CST)\
**Post date:** [March 7, 2022, 9:39am UTC](https://discourse.slicer.org/t/fiducials-in-slicer-4-11-4-10-r-and-a-flipped-coordinates/22342/1 "2022-03-07T09:39:54Z")

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Dear all,

I use Slicer to create Fiducials/annotate landmarks in nifti images for a project. I have multiple computers to work on. After annotating them on computer 1 with Slicer 4.11. I open them on computer 2 with Slicer 4.10 and the points are displayed flipped. When I check the coordinates under the module Markups, they are still the same as in the fcsv file, but I noticed, that in Slicer 4.10. the A coordinates are positive when they are negative in the fcsv file and negative when they are positive in the fcsv in R and A direction.

my point in fcsv file:

> Markups fiducial file version = 4.11  
> CoordinateSystem = LPS  
> columns = id,x,y,z,ow,ox,oy,oz,vis,sel,lock,label,desc,associatedNodeID  
> 1,-0.0034653465346536905,-10.54306930693069,-19.5,0,0,0,1,1,1,0,chiasma,vtkMRMLScalarVolumeNode2

So they same fcsv file looks like this in both Slicers:

- Slicer 4.11: R= +0.003 A= +10.5 S= -19.5
- Slicer 4.10. markup R= -0.003 A= -10.5 S= -19.5

Is there something I do wrong? How can I create files that are the same across versions in Slicer?

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**Author:** ![CST](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/cst/32/6502_2.png) [@CST](https://discourse.slicer.org/u/CST)\
**Post date:** [March 8, 2022, 10:17am UTC](https://discourse.slicer.org/t/fiducials-in-slicer-4-11-4-10-r-and-a-flipped-coordinates/22342/2 "2022-03-08T10:17:59Z")

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In case someone else will ever have this issue. Slicer 4.10. fcsv files look like this:

> Markups fiducial file version = 4.10  
> CoordinateSystem = 0

If I read them into Slicer 4.11. the points are were I would expect them. If I load a fcsv file created with 4.11. into 4.10. it will not take into account LPS System (?) and one has to adjust/flip the files before. The LPS Coordinate System is the one expected by ANTs/ITK so it actually saves you some time if you want to apply transfroms to the fcsv files.

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**Author:** ![dzenanz](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/dzenanz/32/1992_2.png) [@dzenanz](https://discourse.slicer.org/u/dzenanz)\
**Post date:** [March 8, 2022, 2:29pm UTC](https://discourse.slicer.org/t/fiducials-in-slicer-4-11-4-10-r-and-a-flipped-coordinates/22342/3 "2022-03-08T14:29:22Z")

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Here is what I came up with to handle the situation. Upon reading, the coordinates are converted to LPS, unless they are already LPS:

> <https://github.com/KitwareMedical/HASI/blob/0f50ab50d6fb532f4276ca88b244dd3c000a0155/src/hasi/mouse_femur_tibia_ct_morphometry.py#L39-L67>

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [March 9, 2022, 7:04am UTC](https://discourse.slicer.org/t/fiducials-in-slicer-4-11-4-10-r-and-a-flipped-coordinates/22342/4 "2022-03-09T07:04:02Z")

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@CST Is there a specific reason for using a very old Slicer version? You are missing out on hundreds of fixes and new features if you use a Slicer version that was released several years ago.