contourf

contourf(xs, ys, zs; kwargs...)

Plots a filled contour of the height information in zs at horizontal grid positions xs and vertical grid positions ys.

The attribute levels can be either

  • an Int that produces n equally wide levels or bands

  • an AbstractVector{<:Real} that lists n consecutive edges from low to high, which result in n-1 levels or bands

You can also set the mode attribute to :relative. In this mode you specify edges by the fraction between minimum and maximum value of zs. This can be used for example to draw bands for the upper 90% while excluding the lower 10% with levels = 0.1:0.1:1.0, mode = :relative.

In :normal mode, if you want to show a band from -Inf to the low edge, set extendlow to :auto for the same color as the first level, or specify a different color (default nothing means no extended band) If you want to show a band from the high edge to Inf, set extendhigh to :auto for the same color as the last level, or specify a different color (default nothing means no extended band).

If levels is an Int, the contour plot will be rectangular as all zs will be covered. This is why Axis defaults to tight limits for such contourf plots. If you specify levels as an AbstractVector{<:Real}, however, note that the axis limits include the default margins because the contourf plot can have an irregular shape. You can use tightlimits!(ax) to tighten the limits similar to the Int behavior.

Attributes

Available attributes and their defaults for MakieCore.Combined{Makie.contourf, T} where T are:

  colormap      :viridis
  extendhigh    "nothing"
  extendlow     "nothing"
  inspectable   true
  levels        10
  mode          :normal
  nan_color     :transparent
  transparency  false
using CairoMakie
using DelimitedFiles

volcano = readdlm(Makie.assetpath("volcano.csv"), ',', Float64)

f = Figure()
Axis(f[1, 1])

co = contourf!(volcano, levels = 10)

Colorbar(f[1, 2], co)

f

using CairoMakie
using DelimitedFiles

volcano = readdlm(Makie.assetpath("volcano.csv"), ',', Float64)

f = Figure()
ax = Axis(f[1, 1])

co = contourf!(volcano,
    levels = range(100, 180, length = 10),
    extendlow = :cyan, extendhigh = :magenta)

tightlimits!(ax)

Colorbar(f[1, 2], co)

f

using CairoMakie
using DelimitedFiles

volcano = readdlm(Makie.assetpath("volcano.csv"), ',', Float64)

f = Figure()
ax = Axis(f[1, 1])

co = contourf!(volcano,
    levels = range(100, 180, length = 10),
    extendlow = :auto, extendhigh = :auto)

tightlimits!(ax)

Colorbar(f[1, 2], co)

f

Relative mode

Sometimes it's beneficial to drop one part of the range of values, usually towards the outer boundary. Rather than specifying the levels to include manually, you can set the mode attribute to :relative and specify the levels from 0 to 1, relative to the current minimum and maximum value.

using CairoMakie
using DelimitedFiles

volcano = readdlm(Makie.assetpath("volcano.csv"), ',', Float64)

f = Figure(resolution = (800, 400))

Axis(f[1, 1], title = "Relative mode, drop lowest 30%")
contourf!(volcano, levels = 0.3:0.1:1, mode = :relative)

Axis(f[1, 2], title = "Normal mode")
contourf!(volcano, levels = 10)

f