# Overlaying 2d plots of regions with different colors and labels

I'm using the command Show to overlay the following three regions:

r1 = RegionPlot[ 5/2 y + 3 x <= 3 && y < 2/3 && 5/2 y + x <= 2, {x, 0, 1}, {y, 0, 1}]

r2 = RegionPlot[ y < 13/12 - 13/12 x && y < 13/24 , {x, 0, 1}, {y, 0, 1}]

r3 = RegionPlot[y <= 1 - x && y < 2/3 , {x, 0, 1}, {y, 0, 1}]

Show[r1, r2, r3]

The problem is that I can't label them in the final picture and I'd like to change the colors as well to distinguish them more clearly. If possible, I'd like to plot some special points on this picture (like a few of the corners). Is there a "simple" way of doing that?

I'd appreciate any input that you may have. Thanks!

• You get labels and distinct color by combining the equations in one RegionPlot and using PlotLegends option: RegionPlot[{eqs1, eqs2, eqs3}, {x, 0, 1}, {y, 0, 1}, PlotLegends -> {"1", "2", "3"}]. Oct 6, 2020 at 19:55

Something like this?

r1 = RegionPlot[
5/2 y + 3 x <= 3 && y < 2/3 && 5/2 y + x <= 2, {x, 0, 1}, {y, 0,
1}, PlotStyle -> {Opacity[0.2], Yellow},
PlotLabels -> Placed["First region", {.8, .3}]];
r2 = RegionPlot[
y < 13/12 - 13/12 x && y < 13/24, {x, 0, 1}, {y, 0, 1},
PlotStyle -> {Opacity[0.3], Green},
PlotLabels -> Placed["Second region", {.4, .4}]];
r3 = RegionPlot[y <= 1 - x && y < 2/3, {x, 0, 1}, {y, 0, 1},
PlotStyle -> {Opacity[0.5], LightRed},
PlotLabels -> Placed["Third region", {.2, .7}]];
Overlay[{r1, r2, r3}]


• That is perfect, thanks! Is it also possible to plot some of the corners with in the same code? For example, (1/2,13/24) and (1/2,3/5).
– ibr_
Oct 6, 2020 at 21:34
{a, b, c} = {5/2 y + 3 x <= 3 && y < 2/3 && 5/2 y + x <= 2,
y < 13/12 - 13/12 x && y < 13/24, y <= 1 - x && y < 2/3};
RegionPlot[{
Callout[a, "a corner", {1/2, 3/5} + {.1, 0.3}, {1/2, 3/5},
CalloutMarker -> "Arrow", Background -> Blue,
LabelStyle -> White],
Callout[b, "b", {0.2, 13/24} + {0, 0.3}, {0.2, 13/24},
CalloutMarker -> "Arrow"],
Callout[b, "b corner", {1/2, 13/24} + 0.3, {1/2, 13/24},
Appearance -> "Balloon", Background -> Green, LabelStyle -> Gray],
Callout[c, "c", Appearance -> "Arrow", Background -> Red,
LabelStyle -> White]
},
{x, 0, 1}, {y, 0, 1}]