Messages from Usenet group comp.lang.idl-pvwave, compiled by Paulo Penteado
David Fanning has a nice illustration of how to use a linear and a log 'y' axes in the same plot. I have a question that is related to this, but not quite the same. How does one have an upper and a lower x axes, where the lower one in linear and the upper one has *some selected* values of a function of x. The example that comes to mind is the typical Arrhenius plot of y = A*exp(-T0/T), where one plots ln(y) vs 1/T to show the exponential nature of the data. This can be accomplished with plot_oi, 1/T, y, .... Now, how does one plot an upper 'x' axis which gives the corresponding values of T at "convenient" values. Say, that 100 < T < 500 so that the lower axis goes from 0.002 to 0.010. The upper axis should have tick marks and the values at, say, 100, 200, 300, 400 and 500. How does one position the tick marks? Is it at all possible? thanks sj -- Surendar Jeyadev jeyadev@wrc.xerox.com