Click here to see the SAS code.
Click here to see the example.

This example is a little difficult to grasp at first, but try reading what the
color & letter codes stand for, and be aware that it's basically showing 3
things on the same plot at the same time -- once you "get it", you will 
probably agree that this is a useful graph for someone looking to find 
the value/price of a used corvette :-)

I was in the market for a used corvette, and was going through the 
Kelley Blue Book (KBB) to get a bunch of prices - for each year, and each 
model (base model, convertible, and performance Z-model) they list 3
prices (trade-in, private-party, and retail).  It was difficult to 
get a grasp on all this info from the separate tables in KBB, so I 
entered all the data into a sas data set, and plotted it.

Along the bottom x-axis, I list all the years, and each 3-marker
line segment also represents a year & model.  The 3 markers in the line
segment represent the 3 prices (trade-in, private-party, and retail).
I treat these 3 values as if they were stock market high/low/close
values, and use the interpol=hiloct in my symbol statement to 
draw the 3-marker line segments in this way.

Since most people are probably interested in a specific model (base, 
convertible, or performance Z-model), I color-coded each model.
If you're interested in a convertible, just look at the blue markers.

I also used gplot's "html=" option to encode html title= charttips/flyover-text, 
so you can hover your mouse over the markers and see the actual data values.

Some interesting trends & insight into the data...

This plot shows that the base & convertible models are in roughly the
same price range (with the convertibles being a little higher) through 1995, 
and after 1995 the convertibles are priced noticeably higher than the base 
model.  Also the performance ZR1s are *way* higher-priced through 1995
(but in 2001 the Z06 is priced roughly the same as a convertible).

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