MATLAB: How to convert this to the filled 2-D contour plot

contour

I would like to convert the figure below to the one like the filled 2-D contour plot, but don't know how.

This figure is created by:

scatter(X, Y, 500, Z,'filled');

I have attached the data (variables) I used, as well.

FYI: What I meant here as the filled 2-D contour plot

https://jp.mathworks.com/help/matlab/ref/contourf.html

Any comments will be welcomed. Thank you in advance.

Best Answer

load dataset.mat
m = 100 ; n = 100 ; 
x = linspace(min(X),max(X),m) ; 
y = linspace(min(Y),max(Y),n) ; 
[Xi,Yi] = meshgrid(x,y) ; 
Zi = griddata(X,Y,Z,Xi,Yi) ; 
pcolor(Xi,Yi,Zi)
shading interp ;

Related Solutions

MATLAB: How to plot interpolated grid data and original datapoint set in the same plot

You can always simply plot all your points:

plot3(Xi,Yi,Zi,'r.')

Or with scatter:

scatter(Xi,Yi,32,Zi,'filled')

But to me this seems to be more interesting:

pcolor(xi,yi,zi),
% shading flat % or interp adjust shading to fit taste
hold on
plot(xi,yi,'k.','markersize',6)
scatter(contour_grid.X,contour_grid.Y,23,contour_grid.Z,'filled')

Or you could compare contour-plots:

Levels = linspace(min(Zi(:)),max(Zi),10);
contour(Xi,Yi,Zi,Levels,'k')
hold on
tri=delaunay(contour_grid.X,contour_grid.Y);
[c,h]=tricontour(tri,contour_grid.X,contour_grid.Y,contour_grid.Z,Levels);
plot(contour_grid.X,contour_grid.Y,'k.')

You can find the tricontour function on the file exchange: TRICONTOUR

HTH

MATLAB: How to extract the the right X,Y,Z value for obtaining the best contour plot similar than the complete contour

Option 1:

load("A.mat") ; 
x = A(:,1);
y = A(:,2);
z = A(:,3);
m = 21 ; n = 21 ; % can be changed 
xi = linspace(min(x),max(x),m) ; 
yi = linspace(min(y),max(y),n) ; 
[X,Y] = meshgrid(xi,yi) ; 
Z = griddata(x,y,z,X,Y) ; 
idx = ~isnan(Z) ;
iwant = [X(idx) Y(idx) Z(idx)] ;

Option 2:

load("A.mat") ; 
x = A(:,1);
y = A(:,2);
z = A(:,3);
[c,ia,ib] = unique(y) ; 
N = length(c) ;
iwant = cell(N,1) ; 
for i = 1:N
  xi = x(ib==i) ; 
  yi = y(ib==i) ;
  zi = z(ib==i) ; 
  %
  n = round(length(xi)/2) ; % This you can chnage if you want 
  xxi = linspace(min(xi),max(xi),n)' ;
  yyi = c(i)*ones(n,1) ; 
  zzi = interp1(xi,zi,xxi) ; 
  iwant{i} = [xxi yyi zzi] ; 
end
iwant = cell2mat(iwant) ; 
subplot(121)
scatter(x,y,50,z,'filled')
colorbar
title("Original")
subplot(122)
scatter(iwant(:,1),iwant(:,2),50,iwant(:,3),'filled')
colorbar
title("downsampled to best") ;

Best Answer

Related Solutions

MATLAB: How to plot interpolated grid data and original datapoint set in the same plot

MATLAB: How to extract the the right X,Y,Z value for obtaining the best contour plot similar than the complete contour

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