I would to transform scattered data into a surface.
Google told me that is I could do it in Matlab[1,2] or Python [3] using Delaunay triangulation. But I cannot find a similar example in Julia with VoronoiDelaunay.jl and its related pages.
Does anybody has an example ?
Thank you 
[1] Making Surface Plots From Scatter Data - File Exchange - MATLAB Central
[2] Delaunay triangulation - MATLAB delaunay
[3] Use Python to plot Surface graphs of irregular Datasets
You can use a Thin Plate Spline / PolyharmonicSpline to do it.
Here is an old gist that has an Julia v0.5ish implementation and example and here is an updated version that works with Julia v1.0
just for anyone that needs an example with Julia v1.x:
ENV["MPLBACKEND"]="tkagg" # if you need
using PyPlot
using LinearAlgebra
include("polyharmonic_spline.jl")
# contain all code from https://github.com/lstagner/OrbitTomography.jl/blob/master/src/polyharmonic.jl
# and `interpolate()`definition from https://gist.github.com/lstagner/04a05b120e0be7de9915
x,y = randn(500),randn(500)
z = exp.(-(x.^2 .+ y.^2))
S2 = PolyharmonicSpline(2,[x y],z)
n=20
xgrid = ones(n)*range(-3,stop=3,length=n)'
ygrid = range(-3,stop=3,length=n)*ones(n)'
xx = reshape(xgrid,n*n)
yy = reshape(ygrid,n*n)
zz = interpolate(S2,xx,yy)
zgrid = reshape(zz,n,n);
plot_surface(xgrid,ygrid,zgrid,alpha=0.5)
scatter3D(x,y,z,color="r")
show()
With the updated version you don’t need the interpolate method. The constructor for the spline returns a interpolating “function”. You can simplify the code to be
using PyPlot
using LinearAlgebra
include("polyharmonic_spline.jl")
# contain all code from https://github.com/lstagner/OrbitTomography.jl/blob/master/src/polyharmonic.jl
x,y = randn(500),randn(500)
z = exp.(-(x.^2 .+ y.^2))
S2 = PolyharmonicSpline(2,[x y],z)
n=20
xgrid = ones(n)*range(-3,stop=3,length=n)'
ygrid = range(-3,stop=3,length=n)*ones(n)'
zgrid = S2.(xgrid,ygrid) #Take advantage of dot broadcasting
plot_surface(xgrid,ygrid,zgrid,alpha=0.5)
scatter3D(x,y,z,color="r")
show()
