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Is there any way of generating a density plot (or something similar) with one of its axes on a log scale? Essentially I'm trying to combine a LogLinearPlot and a normal Plot on two different variables to create the associated density plot.

If this can't be done directly, what would be the best work-around?

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  • $\begingroup$ If you add a small self-contained example you will get more/better answers. $\endgroup$
    – Ajasja
    Feb 1, 2013 at 13:00
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    $\begingroup$ I can't think of an easier workaround than: DensityPlot[f[x,y], {x, Xmin, Xmax}, {y, Ymin, Ymax}] to DensityPlot[f[x, E^y],{x, Xmin, Xmax}, {y, Log@Ymin, Log@Ymax}]. Adding ticks along y might take you some time but it shouldn't be hard (I've assumed that's the direction you want to log plot) $\endgroup$
    – gpap
    Feb 1, 2013 at 13:13
  • $\begingroup$ I think ScalingFunctions works with DensityPlot... That might help. $\endgroup$
    – cormullion
    Feb 1, 2013 at 17:32
  • $\begingroup$ @cormullion Could you give an example? I can only get it working for the function value but not the axis. (Something like DensityPlot[Sin[x] Sin[y], {x, 1, 10}, {y, 1, 10}, ScalingFunctions -> "Log"]) $\endgroup$
    – Silvia
    Feb 1, 2013 at 18:50
  • $\begingroup$ @silvia no I can't (:-() but I thought there might be those who were clever enough to make it happen... $\endgroup$
    – cormullion
    Feb 1, 2013 at 19:16

1 Answer 1

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Thanks for the input in the comments; here's what I eventually came up with (including tick placement):

fSpace[min_, max_, steps_, f_: Identity] := 
 InverseFunction[f] /@ 
  Range[f@min, f@max, (f@max - f@min)/(steps - 1)]
GetMajorTicks[min_, max_, count_, f_: Identity] := 
  fSpace[min, max, count, f];
GetMinorTicks[min_, max_, majorCount_, minorCount_, f_: Identity] := 
  Flatten[Table[
    Drop[Drop[
      fSpace[x, 
       x ((f@max - f@min)/(majorCount - 1) // InverseFunction[f]), 
       minorCount + 2], 1], -1], {x, 
     Drop[GetMajorTicks[min, max, majorCount, f], -1]}]];

xMin = 1/4;
xMax = 4;
xMajorTicks = 5;
xMinorTicks = 3;
f = Log;
ContourPlot[
 Sin[2 \[Pi] y] InverseFunction[f]@x, {x, f@xMin, f@xMax}, {y, -1, 1},
  FrameTicks -> {{Automatic, 
    None}, {({f@#, # // N} & /@ 
       GetMajorTicks[xMin, xMax, xMajorTicks, f])~
     Join~({f@#, Null, {0.005, 0}} & /@ 
       GetMinorTicks[xMin, xMax, xMajorTicks, xMinorTicks, f]), 
    None}}]

The plot

If this can be cleaned up or improved in any way, I'd love to hear!

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