How does epilog position work in logplots?

Question

I'm trying to use Epilog in my plots but the way that Epilog uses coordinate positions isn't making sense to me. As a minimal example consider,

LogPlot[Sin[x], {x, 0, π}, Epilog -> {Text["x", {π/2, 0.2}]}]

I'd have expected this to put an "x" in the center of the graph but instead it shows up in the corner:

enter image description here

I've also tried ListLogplot and other graphics but they all produce similar results.

How do I force Epilog to use the same positions as the plot?

Note: I'm using Mathematica V10 on Linux.

$\begingroup$ Related: mathematica.stackexchange.com/questions/36753/… $\endgroup$
– Michael E2
Aug 25, 2015 at 11:09 — Michael E2, Aug 25, 2015 at 11:09

Community · Accepted Answer · 2017-04-13 12:55:36Z

16

As shown by the graphic, the Log is applied on the y-axis, thus you need to apply Log to the y coordinate of your point:

LogPlot[Sin[x], {x, 0, π}, Epilog -> {Text["x", {π/2, Log@0.2}]}]

Mathematica graphics

For completeness purposes as suggested by rcollyer:

LogLinearPlot[Tanh[x], {x, 1, 100}, Epilog -> {Text["x", {Log@10, 0.98}]}]

Mathematica graphics

LogLogPlot[
  Sum[i/(x^2 - 2 i 0.99 x + i^2), {i, {1, 10, 100}}], {x, 0.1, 1000}, 
  Epilog -> {Text["x", Log@{10, 10}]}]

Mathematica graphics

CommunityBot

1

answered Jul 15, 2014 at 13:08

Öskå

8,4674 gold badges29 silver badges49 bronze badges

$\begingroup$ Ah, I guess I should have tried that. Perfect, thanks! $\endgroup$
– JeffDror
Jul 15, 2014 at 13:10
$\begingroup$ @JeffDror We all faced the same issue ;o) And for LogLogPlot it has to be applied to both coordinates of course :) $\endgroup$
– Öskå
Jul 15, 2014 at 13:11
$\begingroup$ @Öskå for completeness, would you post examples with LogLinearPlot and LogLogPlot, too? $\endgroup$
– rcollyer
Jul 15, 2014 at 13:14

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