How to visualize 4D data in 2D plane?

You can use principal component analysis to reduce the dimensions. Sklearn has an easy to use package. PCA uses eigen vectors to determine the most 'important' directions in the higher dimensional space and projects the values into the lower dimensional space. Although keep in mind the generated vectors do lose some information from the higher dimensional input.

You can use pairs plot. Look at this link: Visualizing Data with Pairs Plots in Python.

Depending on the data type, you can plot them on a 2d field with the following dimensions: Dim 1-2: X and Y axes Dim 3: plotted point size Dim 4: plotted point color gradient

Or if you do it with a 3D software, you can plot in 3D, with all the point plotted with color gradient. While rotating the field, you can have vision on all dimensions.