MATLAB: 2D density plot with colorbar

imagesc

Hi guys,

I have data which has produced a 2D plot as shown in the first figure.

How can I transform the above figure to appear like the one below?

Best Answer

N = 100 ; 
x = linspace(0,2*pi,N)' ; 
y = sin(x) ; 
xi = linspace(min(x),max(x),N) ; 
yi = linspace(min(y)-1,max(y)+1,N) ; 
[X,Y] = meshgrid(xi,yi) ; 
Z = zeros(size(X)) ; 
idx = knnsearch([X(:) Y(:)],[x y]) ; 
Z(idx) = 1 ; 
Z(idx+1) = 1 ; 
Z(idx-1) = 1 ; 
pcolor(X,Y,Z)
shading interp
colorbar
colormap(jet)

Related Solutions

MATLAB: Create an interpolated grid

% new interpolated grid 

lonx=min_x:20:max_x;
laty=min_y:20:max_y;
[Xi,Yi]=meshgrid(lonx,laty);
bathymetry=interp2(XX,YY,ZZ,Xi,Yi);
%surf(XX,YY,ZZ);

%ZZ(ZZ>0)=nan; 

figure(1)
%pcolor(XX,YY,ZZ),shading interp ,colorbar;

pcolor(Xi,Yi,bathymetry),shading flat ,colorbar;  % if error transpose bathymetry and see
saveas(gcf,'bat_fine','eps');

Also you can striaght away try this:

clear;
format long e
%open file  xyz 
T=readtable('points.txt');
A=T{:,:};
X=A(:,1);
Y=A(:,2);
Z=A(:,3);
min_x=min(X);
max_x=max(X);
min_y=min(Y);
max_y=max(Y);
n=length(X);
% new interpolated grid 
lonx=min_x:20:max_x;
laty=min_y:20:max_y;
[Xi,Yi]=meshgrid(lonx,laty);
bathymetry=interp2(X,Y,Z,Xi,Yi);
ZZ = griddata(X,Y,Z,Xi,Yi);
%surf(XX,YY,ZZ);
%ZZ(ZZ>0)=nan; 
figure(1)
%pcolor(XX,YY,ZZ),shading interp ,colorbar;
pcolor(lonx,laty,bathymetry),shading flat ,colorbar;  % if error transpose the bathymetry 
saveas(gcf,'bat_fine','eps');

MATLAB: How to convert a closed curve into a binary mask

data = importdata('data.txt') ; 
x = data(:,1) ; 
y = data(:,2) ; 
N = 500 ; 
xi = linspace(min(x),max(x),N) ; 
yi = linspace(min(y),max(y),N) ; 
[X,Y] = meshgrid(xi,yi) ; 
idx = inpolygon(X,Y,x,y) ; 
Z = ones(size(X)) ; 
Z(idx) = 0 ; 
imshow(Z)

Best Answer

Related Solutions

MATLAB: Create an interpolated grid

MATLAB: How to convert a closed curve into a binary mask

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