3
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I want to generate a plot like this:

Target plot

I generated this list

list = {{-1., -1, 0}, {-0.894737, -1, 0}, {-0.789474, -1, 0},
{-0.684211, -1, 0}, {-0.578947, -1, 0}, {-0.473684, -1, 0}, 
{-0.368421, -1, 0}, {-0.263158, -1, 0}, {-0.157895, -1, 0}, 
{-0.052631, -1, 0}, {0.0526316, -1, 0}, {0.1578950, -1, 0}, 
{0.2631580, -1, 0}, {0.3684210, -1, 0}, {0.4736840, -1, 0}, 
{0.5789470, -1, 0}, {0.6842110, -1, 0}, {0.7894740, -1, 0}, 
{0.8947370, -1, 0}, {1., -1, 0}}

and I thought that it'll fine for generate the first row, but instead, I get an empty plot using:

ListPlot3D[list]

The only way I'm getting something is taking off the third entry from every triad in the list:

Not desired

But evidently that's not what i'm looking for, thanks in advance.

Edit:
Yeah, my question is not clear, sorry about that. I've generated that list with a Table. What I'm looking for is to plot the square (with 400 equal partitions) centered in the origin of a cartesian coordinates system showing the value of the point. The problem with ArrayPlot is that the axes show the position of the data in the list, and not the value of the point.

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  • 1
    $\begingroup$ Your question is not clear. Do you want to generate that plot with some fake data or want to plot your list? $\endgroup$ – OkkesDulgerci Mar 10 '18 at 3:10
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Is this what you want?

list2 = list[[All, 1]];
Legended[ArrayPlot[list2~Partition~5, 
  ColorFunction -> "WatermelonColors", FrameTicks -> True], 
 BarLegend[{"WatermelonColors", {-1, 1}}]]

enter image description here

Edit:

list = Table[x y, {x, -1, 1, 0.1}, {y, -1, 1, 0.1}];

Legended[ArrayPlot[list, ColorFunction -> "WatermelonColors", 
  Frame -> False, Mesh -> True, MeshStyle -> Black, 
  DataReversed -> True], BarLegend[{"WatermelonColors", {-1, 1}}]]

enter image description here

Edit 2

list = Table[x y, {x, -1, 1, 2/19}, {y, -1, 1, 2/19}];


 ArrayPlot[list, ColorFunction -> "BlueGreenYellow", Frame -> False, 
 Mesh -> True, MeshStyle -> Black, DataReversed -> True, 
 PlotLegends -> Automatic]

enter image description here

Edit 3 You can remove the GridLines

list = Table[x y, {x, -1, 1, 2/19}, {y, -1, 1, 2/19}]; p2 = 
 ArrayPlot[list, ColorFunction -> "BlueGreenYellow", Mesh -> True, 
  MeshStyle -> Black, ImagePadding -> None, DataReversed -> True, 
  Frame -> False, ImageSize -> 95];
p1 = ListPlot[{{0, 0}}, Frame -> True, Axes -> False, 
   PlotRange -> {{-4, 4.4}, {-2, 2.4}}, ImageSize -> 400, 
   AspectRatio -> Full, 
   FrameTicks -> {{{-2, -1, 0, 1, 2}, None}, {{-4, -2, 0, 2, 4}, 
      None}}, GridLines -> {{-1, 0, 1}, {-1, 0, 1}}];
Legended[Overlay[{p1, p2}, Alignment -> Center], 
 BarLegend[{"BlueGreenYellow", {-1, 1}}, LegendMarkerSize -> 200, 
  Ticks -> {-1, -0.5, 0, 0.5, 1}]]

enter image description here

Edit 4 Here is better and perfect figure.(I assume you don't insist black mesh on figure). I got the idea from here

  data = Reverse@Table[x y, {x, -1, 1, 2/19}, {y, -1, 1, 2/19}];
renderImage[array_?MatrixQ, cf_, q_Integer: 2048, 
  opts : OptionsPattern[Image]] := 
 Module[{tbl}, 
  tbl = List @@@ Array[cf, q, {0`, 1`}] // N // 
    Developer`ToPackedArray;
  Image[tbl[[# + 1]] & /@ Round[(q - 1`) array], opts]]
img = renderImage[Rescale[data], ColorData["BlueGreenYellow"]];

Legended[Graphics[Inset[img, {-1, -1}, {0, 0}, {2, 2}], Axes -> True, 
  Frame -> True, 
  FrameTicks -> {{{-2, -1, 0, 1, 2}, None}, {{-4, -2, 0, 2, 4}, 
     None}}, PlotRange -> {{-4, 4}, {-2, 2}}, 
  GridLines -> {{-1, 0, 1}, {-1, 0, 1}}], 
 BarLegend[{"BlueGreenYellow", {-1, 1}}, LegendMarkerSize -> 200, 
  Ticks -> {-1, -0.5, 0, 0.5, 1}]]

enter image description here

enter image description here

Here how you can add Mesh on plot.

data = Table[{x, y}, {x, -1, 1, 2/19}, {y, -1, 1, 2/19}];
grid = Extract[#, {{1}, {-1}}] & /@ data;
grid2 = Extract[#, {{1}, {-1}}] & /@ Transpose@data;
Legended[Graphics[{Inset[img, {-1, -1}, {0, 0}, {2, 2}], Black, 
   Opacity@1, Line[#] & /@ grid1, Line[#] & /@ grid2}, Frame -> True, 
  FrameTicks -> {{{-2, -1, 0, 1, 2}, None}, {{-4, -2, 0, 2, 4}, 
     None}}, PlotRange -> {{-4, 4}, {-2, 2}}, AspectRatio -> 1/2], 
 BarLegend[{"BlueGreenYellow", {-1, 1}}, LegendMarkerSize -> 200, 
  Ticks -> {-1, -0.5, 0, 0.5, 1}]]

enter image description here

Can someone explain why this does not work well? img should fit [-1,1]x[-1,1]

data = Table[x y, {x, -1, 1, 2/19}, {y, -1, 1, 2/19}];
img = ArrayPlot[data, ColorFunction -> "BlueGreenYellow", 
  Mesh -> True, MeshStyle -> Black, DataReversed -> True, 
  ImageMargins -> 0, ImagePadding -> None, 
  ImageSize -> 270]; Graphics[Inset[img, {-1, -1}, {0, 0}, {2, 2}], 
 Axes -> True, Frame -> True, PlotRange -> {{-4, 4}, {-2, 2}}, 
 FrameTicks -> {{{-2, -1, 0, 1, 2}, None}, {{-4, -2, 0, 2, 4}, None}},
  GridLines -> {{-1, 0, 1}, {-1, 0, 1}}, AspectRatio -> Automatic]

enter image description here

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  • $\begingroup$ It looks like that. Maybe I need to manipulate your code, or my list. I want a plot of a square from [-1,1]x[-1,1] with 20 squares per side. Let me work on it and I tell you. $\endgroup$ – Joaquín Rico Mar 10 '18 at 3:35
  • $\begingroup$ you should replace 0.1 with 2/19 to get 20 square per side in Table $\endgroup$ – OkkesDulgerci Mar 10 '18 at 3:44
  • $\begingroup$ Wow, thanks man, that's what I needed! $\endgroup$ – Joaquín Rico Mar 10 '18 at 6:36
  • $\begingroup$ Thanks again!! Now i'm know about this functions, it's been very helpfu! $\endgroup$ – Joaquín Rico Mar 11 '18 at 3:22
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Here's another simple way using ListDensityPlot which is in some sense the "right" way if this data is to be interpreted as continuous.

ListDensityPlot[list = Table[x y, {x, -1, 1, 0.1}, {y, -1, 1, 0.1}], 
 ColorFunction -> "BlueGreenYellow", Mesh -> True, MeshStyle -> Black]

enter image description here

If you want the plot legend PlotLegends -> Automatic will do that for you.

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