Contour plots with irregular grids

Hi,

I am trying to create a filled contour plot with my x axis(first column), y axis(second column), and temperature(third column) data. I tried plotting it using griddata but it interpolates my data incorrectly. Is there any way I can plot the contour plots? I have attached my data for the coordinates and temperature and a figure of the contour of how it should look like.

Thank you.

Answer 1

[Akira Agata]

How about the following?

% Read data file
tData = readtable('data.xlsx');
tData.Properties.VariableNames = {'x','y','TEMP'};

% Apply interpolation
[x1,y1] = meshgrid(-0.045:0.00005:-0.02, 0.01:0.00005:0.035);
z1 = griddata(tData.x, tData.y, tData.TEMP, x1, y1);

% Set the TEMPs outside the measured area to NaN
k = boundary(tData.x, tData.y, 1);
pgon = polyshape(tData.x(k), tData.y(k),'Simplify',false);
idx = isinterior(pgon,x1(:),y1(:));
idx = reshape(idx,size(x1));
z1(~idx) = nan;

% Show the result
figure
contourf(x1,y1,z1,'ShowText','on');
caxis([-50 441]);
axis equal
xlabel('x, (mm)')
ylabel('y, (mm)')
title('temperature(C)@213k800ms contour plot')
colorbar

[CAL]

Thank you very much for the solution and have a good day!

[Jack Lavender]

Hi, I have a similar problem:

It's the result of a CFD simulation with periodic boundaries so to view it I'm copying a data set twice with a shift in x and y.

There are duplicate points in the resultant set of points. It has an irregular boundary and internal holes.

This is what I'm hoping for (except not ctrl v):

and this is what I have so far.

thank you very much in advance for your time!

Jack