why some of the atlases on cellxgene do not have PCA in them. How can we use them to annotate our sample.

[Sirin24]

why some of the atlases on cellxgene do not have PCA in them. How can we use them to annotate our sample? as most tools require the presence of PCA to create models for annotation.

We need from scratch to preproccess such objects.

I am talking about the Human brain atlas 1.0. Unfortunately, it comes only with the annotation of the cells and we need to compute the PCA which requires a lot of ram and the resulting umap is not the same as the original. is there a way to query our sample directly onto cellxgene to annotate them? or it possible that all object come with a PCA so that an atlas is truly an atlas and everyone uses it as is. and whoever wants to change this around is free to do some preprocessing if needed.