# Relationship between space and SPHARM coefficients

**URL:** https://discourse.slicer.org/t/relationship-between-space-and-spharm-coefficients/2948
**Category:** Support
**Created:** [May 28, 2018, 7:32am UTC](https://discourse.slicer.org/t/relationship-between-space-and-spharm-coefficients/2948 "2018-05-28T07:32:29Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![doganarda](https://avatars.discourse-cdn.com/v4/letter/d/f05b48/32.png) [@doganarda](https://discourse.slicer.org/u/doganarda)
#### Post date: [May 28, 2018, 7:32am UTC](https://discourse.slicer.org/t/relationship-between-space-and-spharm-coefficients/2948/1 "2018-05-28T07:32:29Z")

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Greetings everyone,

I have (probably a dumb) question - not really related to the software but more related to the concept of SPHARM coefficients. I am using SPHARM-PDM to extract SPHARM coefficients of various subcortical brain regions (e.g, Hippocampus, Caudate, etc.) and even though I am able to visualize the phi, phi half and theta maps, I believe these maps show which point on the structure corresponds to which point on the sphere (given its phi and theta value). So I was wondering, is there any way to relate the SPHARM coefficients of a given structure to its spatial regions - to make the question more simple: is there any way to determine how, for example, posterior hippocampus is represented etc. I personally believe that it is not possible to create a link between SPHARM coefficients and the spatial properties of the given structure in an obvious way - just thinking about an analogy between 2D fourier series and the function it is represents (no way to tell, I think, from sines and cosines). But in the slightest chance that I am missing something - which is possible because I am not that familiar with SPHARM analysis - I wanted to give it a shot.

Best regards to everyone,  
Arda