How to draw (intuitively) the first and second principal component in PCA methods? Assume I have some data in 2D. How to draw the first and second principal component in PCA method?

By referring to the image: the plot on the right is confusing, how I can detect the position of first PCA?
In the case of 2d data, the first principal component will be aligned along the direction of major continuity, and the second will be perpendicular to that, aligned along the least continuous direction. Generally just the eigen vectors at the mean x / mean y.

Sort of like so (sorry for the poor drawing)



My favorite reference on pca is A TUTORIAL ON PRINCIPAL COMPONENT ANALYSIS by Jon Shlens: pdf His example is in figure 2.

To address your comment: