How to smooth the edges in my contour plot corresponding to nan

Question

This is the link to the dataset. I have this contour plot which has a bit rough edges. My question is, how can I smooth these edges these edges correspond to Nan. I filled in the Z matrix with Nan so as to remove unwanted values.

I also wanted to ask that why shading flat and interp is not working on this contour.

I have set shading to flat and in Matlab2013b I get proper flat figure but in Matlab 2014b and 2015b I am getting this figure.

MATLAB 2015b:

MATLAB 2013b

How can I obtain perfectly meshed plot in Matlab 2015b, I checked for shading options in the documentation and there are only 3 faceted, interp and flat.

shading flat works in 2013b but not in subsequent versions. Can someone tell me why is it so?

This is the sample code which I am using right now:

clear all; close all; clc;

load temperature.txt;

time = temperature(:,1);               % This column contains the time
x = temperature(:,2);                  % This column contains the x values.
temperature_system = temperature(:,3); % This column contains the temperatures.

% Rejecting the outliers
pos = (temperature_system > prctile(temperature_system,97));
time(pos) = [];
x(pos) = [];
temperature_system(pos) = [];

X1 = [time x];


F = scatteredInterpolant(X1,temperature_system);
x1 = linspace(min(x),max(x),100);
x2 = linspace(min(time),max(time),100);
[X,Y] = meshgrid(x2,x1);
Z = F(X,Y);

% Is the data below the criteria for all points in space at a specific time
emptyTime = all(Z<10,1);
emptySpace = all(Z<10,2);
[emptyTime, emptySpace] = meshgrid(emptyTime, emptySpace);
Z(emptyTime | emptySpace) = nan;

% Replacing the remaining zeros with nan
pos = find(Z<1);
Z(pos) = nan;
f1 = figure(1);
%set(f1,'renderer','zbuffer');

%surf(X,Y,Z);

[C,h] = contourf(X,Y,Z, 'Linestyle', 'none');
shading flat;
colormap(jet);
q = colorbar;
set(q,'direction','reverse');
q.Label.String = 'Temperature';


xlabel('Time (ps)','FontSize', 16, 'FontWeight', 'bold',...
   'FontName', 'Helvetica', 'Color', 'Black');
ylabel('Length of box (A)','FontSize', 16, 'FontWeight', 'bold',...
    'FontName', 'Helvetica', 'Color', 'Black');

set(gca,'LineWidth',3,'TickLength',[0.02 0.02]);
set(gca,'XMinorTick','on');
set(gca,'YMinorTick','on','XTicksBetween', 5);
set(gca,'FontSize',12,'FontName','Helvetica');

Answer 1

It's difficult to test the issue without having your data. I got rid of the lines by means of the LineStyle property:

Code:

Z = peaks(20);
subplot(2,1,1);
contourf(Z,10);
colorbar;
subplot(2,1,2);
contourf(Z,10, 'LineStyle', 'none');
colorbar;