Bar legend coloring doesn't correspond to array plot coloring in the expected way

Question

Execute this code:

ArrayPlot[RandomReal[{-1, 1}, {10, 10}],
 PlotLegends -> BarLegend[{"BrownCyanTones", {-5, 1}}],
 ColorFunction -> ColorData[{"BrownCyanTones", {-5, 1}}],
 PlotRange -> {-5, 1},
 ColorFunctionScaling -> False]

In my PC (Xubuntu 15.04, Mathematica 10.3) this returns:

You can see that the BarLegend is wrong, it should be:

which is what I get if I had executed BarLegend[{"BrownCyanTones", {-5, 1}}] directly.

Is this a bug? How can I fix it?

Answer 1

You are using it wrong. The default algorithm for PlotLegends will supply the correct ColorFunction to BarLegend, so use

ArrayPlot[RandomReal[{-1, 1}, {10, 10}], 
  PlotLegends -> Automatic, 
  ColorFunction -> ColorData[{"BrownCyanTones", {-5, 1}}], 
  PlotRange -> {-5, 1}, ColorFunctionScaling -> False]

If you need to modify the legend, you can do so without mishap by using Automatic, e.g.

PlotLegends -> BarLegend[Automatic, LegendLayout -> "Row"]
PlotLegends -> BarLegend[{Automatic, {-10, 10}}]
PlotLegends -> BarLegend[Automatic, 5 (*contours*)]

etc.

Answer 2

Can confirm this happens in 10.3 Win 7 Pro 64 bit.

You can get around it with Legended.

Legended[
 ArrayPlot[RandomReal[{-1, 1}, {10, 10}], 
  ColorFunction -> ColorData[{"BrownCyanTones", {-5, 1}}], 
  PlotRange -> {-5, 1}, ColorFunctionScaling -> False],
 BarLegend[{"BrownCyanTones", {-5, 1}}]]

Hope this helps.

Answer 3

To my mind there are four ways of making the array plot with the BrownCyanTones gradient and a bar legend that seem reasonable.

Data range -1 to 1, plot range -1 to 1, lengend range -1 to 1

SeedRandom[1];
ArrayPlot[RandomReal[{-1, 1}, {10, 10}],
  ColorFunction -> "BrownCyanTones",
  PlotLegends -> BarLegend[{"BrownCyanTones", {-1, 1}}]]

Data range -5 to 1, plot range -5 to 1, lengend range -5 to 1

SeedRandom[1];
ArrayPlot[RandomReal[{-5, 1}, {10, 10}],
  ColorFunction -> "BrownCyanTones",
  PlotLegends -> BarLegend[{"BrownCyanTones", {-5, 1}}]]

Data range -1 to 1, plot range -1 to 1, legend colors taken from the upper part of BrownCyanTones

SeedRandom[1];
ArrayPlot[RandomReal[{-1, 1}, {10, 10}], 
  ColorFunction -> ColorData[{"BrownCyanTones", {-1, 1}}],
  PlotLegends -> BarLegend[{ColorData[{"BrownCyanTones", {-1, 1}}], {-1, 1}}]]

Data range -1 to 1, plot range -5 to 1, lengend range -5 to 1

SeedRandom[1];
ArrayPlot[RandomReal[{-1, 1}, {10, 10}], 
  ColorFunction -> ColorData[{"BrownCyanTones", {-1, 1}}],
  PlotRange -> {-5, 1},
  PlotLegends -> BarLegend[{"BrownCyanTones", {-5, 1}}]]

I can't figure out from your question which of these is what you are after, but one of them should work. They all have the property that the bar legend colors match the plot colors.