Skip to main content

plotting - List Contour Plot: Delete some contour lines, but keep the colors


I'm trying to make a ContourPlot of a set of data of the kind: $(x,y,f(x,y))$


What I'd like to do is to remove the majority of the iso-line and just leave two of them, but keeping the changing of the color.


In other words I'd like to obtain something like a ListDensityPlot of my data set, but with two iso-curves marking the points $(x,y)$ having either value $0$ or $-0.0005$.


Any idea on how to do this? like for example overlapping two different graphs on each other or extracting the iso-curve interpolant from the contour plot and plug it into the density plot? these are just some ideas...



Answer




data = Table[Sin[i + j^2], {i, 0, 3, 0.05}, {j, 0, 3, 0.05}];

ListContourPlot[data, ColorFunction -> "Rainbow", 
 Contours -> {{0, {Thick, Black}}, {-.5, {Thick, Dashed, Black}}, 
               Sequence @@ ({#, None} & /@ Range[Min@data, Max@data, .0025])}]

enter image description here


You can also use the desired contours as Epilog with ListDensityPlot:


lcp = ListContourPlot[data, ContourShading -> None,
   Contours -> {{0, {Thick, Black}}, {-.5, {Thick, Dashed, Black}}}];

ListDensityPlot[data, ColorFunction -> "Rainbow", Epilog -> lcp[[1]]]

enter image description here


Or, to use default contour styles, use Contours -> {0, -.5} in lcp to get


ListDensityPlot[data, ColorFunction -> "Rainbow", Epilog -> lcp[[1]]]

enter image description here


Update: You can also use Mesh and MeshFunctions with ListDensityPlot:


ListDensityPlot[data, ColorFunction -> "Rainbow", MeshFunctions -> {#3 &},  Mesh -> {{0., -.5}}]


enter image description here


Comments

Post a Comment

Popular posts from this blog

front end - keyboard shortcut to invoke Insert new matrix

I frequently need to type in some matrices, and the menu command Insert > Table/Matrix > New... allows matrices with lines drawn between columns and rows, which is very helpful. I would like to make a keyboard shortcut for it, but cannot find the relevant frontend token command (4209405) for it. Since the FullForm[] and InputForm[] of matrices with lines drawn between rows and columns is the same as those without lines, it's hard to do this via 3rd party system-wide text expanders (e.g. autohotkey or atext on mac). How does one assign a keyboard shortcut for the menu item Insert > Table/Matrix > New... , preferably using only mathematica? Thanks! Answer In the MenuSetup.tr (for linux located in the $InstallationDirectory/SystemFiles/FrontEnd/TextResources/X/ directory), I changed the line MenuItem["&New...", "CreateGridBoxDialog"] to read MenuItem["&New...", "CreateGridBoxDialog", MenuKey["m", Modifiers-...
Post a Comment
Read more

How to thread a list

I have data in format data = {{a1, a2}, {b1, b2}, {c1, c2}, {d1, d2}} Tableform: I want to thread it to : tdata = {{{a1, b1}, {a2, b2}}, {{a1, c1}, {a2, c2}}, {{a1, d1}, {a2, d2}}} Tableform: And I would like to do better then pseudofunction[n_] := Transpose[{data2[[1]], data2[[n]]}]; SetAttributes[pseudofunction, Listable]; Range[2, 4] // pseudofunction Here is my benchmark data, where data3 is normal sample of real data. data3 = Drop[ExcelWorkBook[[Column1 ;; Column4]], None, 1]; data2 = {a #, b #, c #, d #} & /@ Range[1, 10^5]; data = RandomReal[{0, 1}, {10^6, 4}]; Here is my benchmark code kptnw[list_] := Transpose[{Table[First@#, {Length@# - 1}], Rest@#}, {3, 1, 2}] &@list kptnw2[list_] := Transpose[{ConstantArray[First@#, Length@# - 1], Rest@#}, {3, 1, 2}] &@list OleksandrR[list_] := Flatten[Outer[List, List@First[list], Rest[list], 1], {{2}, {1, 4}}] paradox2[list_] := Partition[Riffle[list[[1]], #], 2] & /@ Drop[list, 1] RM[list_] := FoldList[Transpose[{First@li...
Post a Comment
Read more

mathematical optimization - Minimizing using indices, error: Part::pkspec1: The expression cannot be used as a part specification

I want to use Minimize where the variables to minimize are indices pointing into an array. Here a MWE that hopefully shows what my problem is. vars = u@# & /@ Range[3]; cons = Flatten@ { Table[(u[j] != #) & /@ vars[[j + 1 ;; -1]], {j, 1, 3 - 1}], 1 vec1 = {1, 2, 3}; vec2 = {1, 2, 3}; Minimize[{Total@((vec1[[#]] - vec2[[u[#]]])^2 & /@ Range[1, 3]), cons}, vars, Integers] The error I get: Part::pkspec1: The expression u[1] cannot be used as a part specification. >> Answer Ok, it seems that one can get around Mathematica trying to evaluate vec2[[u[1]]] too early by using the function Indexed[vec2,u[1]] . The working MWE would then look like the following: vars = u@# & /@ Range[3]; cons = Flatten@{ Table[(u[j] != #) & /@ vars[[j + 1 ;; -1]], {j, 1, 3 - 1}], 1 vec1 = {1, 2, 3}; vec2 = {1, 2, 3}; NMinimize[ {Total@((vec1[[#]] - Indexed[vec2, u[#]])^2 & /@ R...
Post a Comment
Read more