# IGPlanarEmbedding description

**URL:** <https://igraph.discourse.group/t/igplanarembedding-description/768>\
**Category:** Usage\
**Tags:** Mathematica\
**Created:** [3 June 2021 09:52 UTC](https://igraph.discourse.group/t/igplanarembedding-description/768 "2021-06-03T09:52:38Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Jonathan](https://yyz2.discourse-cdn.com/free1/user_avatar/igraph.discourse.group/jonathan/32/320_2.png) [@Jonathan](https://igraph.discourse.group/u/Jonathan)\
**Post date:** [3 June 2021 09:52 UTC](https://igraph.discourse.group/t/igplanarembedding-description/768/1 "2021-06-03T09:52:38Z")

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Hi,

I want to know how exactly the function IGPlanarEmbedding works in iGraph/M.  
I found in the repo, a file describing it, but I don’t understand the details.  
"[IGPlanarEmbedding[graph] gives a planar combinatorial embedding of a graph."](https://github.com/szhorvat/IGraphM/blob/fe1cc53877dfdab441c8a47cd45ef8a28e4d807c/IGraphM/PlanarGraphs.m#L157)  
Can someone explain/unpack its functioning?

Best,

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<div class="post-metadata">

**Author:** ![szhorvat](https://yyz2.discourse-cdn.com/free1/user_avatar/igraph.discourse.group/szhorvat/32/3_2.png) [@szhorvat](https://igraph.discourse.group/u/szhorvat)\
**Post date:** [3 June 2021 20:51 UTC](https://igraph.discourse.group/t/igplanarembedding-description/768/2 "2021-06-03T20:51:46Z")

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To learn more about a function, instead of browsing the source code, first look at the documentation. You can open it with `IGDocumentation[]` and search for `IGPlanarEmbedding`.

[http://szhorvat.net/mathematica/IGDocumentation/#igplanarembedding](http://szhorvat.net/mathematica/IGDocumentation/#igplanarembedding)

This function returns a planar [combinatorial embedding](https://en.wikipedia.org/wiki/Rotation_system) of a planar graph. The “Planar Graphs” section of the documentation gives a brief explanation of what a combinatorial embedding is.

[http://szhorvat.net/mathematica/IGDocumentation/#planar-graphs](http://szhorvat.net/mathematica/IGDocumentation/#planar-graphs)

As for _how_ it works, it uses the [LEMON graph library](https://lemon.cs.elte.hu/), which implements [the Boyer-Myrvold algorithm](https://doi.org/10.7155%2Fjgaa.00091).