timefmt with splot?

[Colin Telmer]

I have being trying to get the y axis in a non-parametric splot to display
a time range rather than the column index of the matrix I am plotting. I
have yet to suceed. Before I try to describe how I have approached this,
here is exactly what I want without the timefmt:

gset nokey 
gset xlabel "Maturity\\n (Years)" 5,-1 
gset xrange [0:10] reverse 
gset ylabel "Time" 0,-1 
gset zlabel "Percent" -9,-6 
gset hidden3d;  
gset data style lines; 
gset surface;  
gset nocontour;  
gset noparametric;  
gset view 65, 70, 1,1.75;  
gsplot nr';  

It is 3d plot with time on the y axis, bond maturity on the x axis and the
rate of return on the z axis in percentage points. The xrange is reversed
as I want the short maturities at the front. The y axis at the moment runs
from 0 to 500 which roughly corresponds to monthly data from 1/52 to 2/92.
>From this I have tried a bunch of different combinations (even just within
gnuplot) to get 1/52 to 2/92 along the y axis. My latest failure was along
the lines of:

gset data style lines;
gset xlabel "Maturity";
gset ylabel "Date";
gset timefmt "%m/%y";
gset ydata time;
eval(["gset yrange [\"1/52\":\"2/91\"]"]);
gset hidden3d;
gset surface;
gset nocontour;
gset noparametric;
gset view 65, 50, 1, 1.75;
gset format y "%m/%y";
gsplot nr

The error I get is 

gnuplot> sp "/tmp/oct-13906aaa" t "line 1" w lines
                                ^
         line 0: Need full using spec for y time data

I have tried to use "using" but I cannot figure out what arguments to
pass to it. Any ideas? 

Any help is gratefully appreciated. 

Cheers, Colin.

--
Colin Telmer, Ottawa, Ontario, Canada
<mailto:address@hidden>
<http://www.telmer.com>