Aerial and Four Point Lineal Perspective on Location
(en plein air)

I like to think of Ring#5 as a mile out, That's easy to remember, Ring#7 is actually a mile in distance away from you. The important thing is changing pigment color for your shadows and highlight colors again after one mile's distance. The distance between the ten concentric rings really starts to increase from there out. These are the values on a clear day at noon.

Ring 1, is about 10 yards (9.14 m) distance from you, you should first notice a value difference here, find some objects to mark this distance. Many objects in a row are nice. Within this first ring are the darkest dark shadows, not to be repeated again in any other ring. Magenta and Green make the darkest neutral shadows in the foreground.

Ring 2, 15 to 25 yards (13.70 to 22.86 m) away from you. The darkest shadows may be an ultramarine blue and burnt umber mix depending on the time of day.

Ring 3, is 25 to 55 yards (22.86 - 50.29 m) away from you. These color changes are obvious when you pick your colors at these distances.

Ring#4. Here starts the addition of a minimal portion of the split analogious Green and Purple color mixed 1:1.
Ring#5 is a little less than one mile in distance from you. The shadow and highlight colors are getting tints lighter with the added purple and green mix which makes a bluish distance color.
Ring#6, Ultramarine blue is added to the analogous purple and green mix.
Ring#7 is one mile out there.
Ring#8 is 20 to 50 miles away from you, there is not much color change between 20 and 50 miles.
Ring#9 The tint of ultramarine blue changes to cobalt blue.
Ring#10, is very far away, more than one hundred miles and the mountain colors are very close to the sky color.