[Gnuplot-info] Creating Stiff Diagrams

[No S. <ly...@ym...>]

Hello,

I am new to gnuplot, and am hoping I might be able to use it to create Stiff diagrams (link to wikipedia)--basically I want to plot some irregular hexagons that convey some information about ion composition in waters. My explanation will hopefully make more sense if you first view the example diagram on wikipedia.

Plotting polygons looks fairly simple and straightforward, but only if I arbitrarily insert numbers I need. I am wondering if I can make a custom plot where the x axis is symmetrically bound (0, 20), left and right of 0, e.g. (+20----+10-----0----+10----+20), and the y axis has fixed values for specific ions.  Is there a way to map a text label for the ions to a specific numerical value, and have no intervening numerical values?
For instance, if I will always have variables, a, b, c to the left of 0, a*,b*, c* to the right of 0, mapped to the same y-value constants (the ion of interest):
(a, -1), (a*, -1*)
(b, -8), (b*, -8*)
(c, -15), (c*, -15*)

where,
-1, -8, -15 are just arbitrary positions for plotting the ion names (3 to left of 0, 3* to the right of 0). I looked through demo graphs and starting browsing through tutorials, but I didn't see anything immediately applicable. Where should I start? Any pointers?

Thank you for reading!

Joseph