Hi @hsapers!

Let's take a peek at the docs for the `heatmap`

visualizer:

```
--p-metric TEXT Choices('canberra', 'correlation', 'jaccard',
'cityblock', 'kulsinski', 'hamming', 'sokalsneath', 'mahalanobis', 'dice',
'minkowski', 'cosine', 'matching', 'euclidean', 'sqeuclidean',
'sokalmichener', 'rogerstanimoto', 'russellrao', 'seuclidean',
'braycurtis', 'yule', 'chebyshev')
Metrics exposed by seaborn (see
http://seaborn.pydata.org/generated/seaborn.clusterma
p.html#seaborn.clustermap for more detail).
[default: 'euclidean']
--p-method TEXT Choices('average', 'complete', 'weighted', 'centroid',
'single', 'ward', 'median')
Clustering methods exposed by seaborn (see
http://seaborn.pydata.org/generated/seaborn.clusterma
p.html#seaborn.clustermap for more detail).
[default: 'average']
```

Okay, focusing in on the `method`

parameter for now, let's check out that link:

http://seaborn.pydata.org/generated/seaborn.clustermap.html#seaborn.clustermap

Linkage method to use for calculating clusters. See `scipy.cluster.hierarchy.linkage()`

documentation for more information.

Wow, this is turning into a game of telephone. Let's check out that scipy link in there:

https://docs.scipy.org/doc/scipy/reference/generated/scipy.cluster.hierarchy.linkage.html#scipy.cluster.hierarchy.linkage

Okay, now that we have some docs on hand:

I don't think that's always the case. Let's put it this way, this QIIME 2 plugin is not computing the metric before handing off the data to seaborn to plot, we're just exposing the seaborn function here. According to the scipy docs:

**metric** str or function, optional

The distance metric to use in the case that y is a collection of observation vectors; ignored otherwise. See the `pdist`

function for a list of valid distance metrics. A custom distance function can also be used.

So the metric is only used as part of the clustering algorithm, and isn't applied to the final table.

It depends on which axis you choose to cluster on:

```
--p-cluster TEXT Choices('features', 'both', 'none', 'samples')
Specify which axes to cluster. [default: 'both']
```

Hope that helps! Sorry for the game of telephone with the docs...