First of all, sorry for the strange title, I had no idea how to describe my problem better. My issue is the following, I think it is pretty much limited to geosciences.
I have several properties for every sample, which are divided by depth.
(ID var1_0-20cm, var1_20-50cm, var1_50-100cm, var2_0-20cm, var2_20-50, ....)
(1, 2.3, 2.1, 2.6, 10.5, 10.9, 15.0,...)
(2, 2.0, 1.1, 1.1, 5.5, 5.9, 5.0,...)
(3, 1.0, 0.0, 0.0, 3.5, 1.9, 1.0,...)
Basically these are geological layers going from surface down to 100 cm depth. I am trying to decrease the number of variables, either with PCA or factor analysis. The issue is, that I would like to handle properties together, no matter what the depth is.
(For instance I do not want to get rid of a layer in between the surface and the bottom layer.)
Is there any way to handle them together, or group them for PCA or whatever. I tried to find some relevant information, but I think the problem is limited to a small portion of the science (maybe I am wrong), so I could not find anything useful.