When use standardization, normalization or both?

I have a dataset with variables with different scales as shown in the figure below. I need to group individuals together and I'm testing algorithms like Kmeans and DBScan. In all tests I'm extracting the two main components with PCA.

When I don't apply any transformation before PCA (neither standardization nor normalization), almost all individuals are in a single cluster. The same happens when I apply one or another transformation (standardization OR normalization).

I only get meaningful results if I apply both (standardization AND normalization).

But I'm in doubt if I'm doing the correct method here, that is, if I apply the two transformations it wouldn't be causing problems in my results.

What do you think?

Topic normalization preprocessing dbscan clustering

Category Data Science

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