How to specify the color of this contourf plot?

I'm trying to plot the landmask (logical 0 or 1) using a uniform color. Below is my code:

% Turning the landmask from logical to numerical. 
M = NaN(landmask);
M(landmask) = 1;
[C1, h1] = m_contourf (X, Y, M, [1, 1]); %This is the contour I need help with.
hold on
% another contourf plot:
[C2, h2] = m_contourf (X, Y, Z2, [-5:1:45], 'LineStyle', 'none' );
caxis([0 45]);

How do I specify the color of the first contour to a uniform color of [0.7 0.7 0.7]?

I tried the below and it did not work.

[C1, h1] = m_contourf (X, Y, M, [1, 1], 'color', [0.7 0.7 0.7] );

Right now, its color is basically dictated by the "caxis([0 45])" command the same way as the 2nd contourf plot.

Thanks.

Answer 1

[Bjorn Gustavsson]

Maybe you can avoid the problem by using fill or patch by extracting the coordinates of the perimeters of the landmask?

Something like this:

[C1, h1] = m_contourf (X, Y, M, [1, 1]);
i1 = 1;
i2 = C1(2,i1);
idxPatch = 1;
while i1 < size(C1,2)
  i2 = C1(2,i1);
  i1 = i1+1;
  hF(idxPatch) = fill(C1(1,i1:(i1+i2-1)),C1(2,i1:(i1+i2-1)),[0.7 0.7 0.7]);
  hold on
  idxPatch = idxPatch + 1; % yeah, yeah, dynamically growing hF but too much work to find out how many fields in landmask...
  i1 = i2+i1;
end

Now you should've replaced the contour-patches with regular patches where you can controll the colour directly (in my matlab-version there's no obvious color or facecolor property of the h1).

HTH

[Leon]

Many thanks. I just gave it a try and got the below error:

Index in position 2 exceeds array bounds.
i2 = C1(2,i1);

Size(C1) gives me a 2 x 0 answer.

[Bjorn Gustavsson]

Oops. It just dawned on me that I used the plain contourf function for my example. Which m_contourf are you using?

The test-example I used was:

[C1,c2] = contourf(peaks(123),[1 1]*2.3);
i1 = 1;
hold on
while i1 < size(C1,2)
  i2 = C1(2,i1);
  i1 = i1+1;
  fill(C1(1,i1:(i1+i2-1)),C1(2,i1:(i1+i2-1)),[0.7 0.7 0.7])
  i1 = i2+i1;
end

That you get an empty array out from m_contourf indicates that you should have no contours returned from the function? (according to the help for the m_contourf-function I have it should return a C1 in the same manner as the built-in contourf-function, but my version is a user-developed tool...)

[Leon]

Thank you! I tried "contourf" and it gave me the same issue, i.e., size(C1) is 2 x 0.

Please see attached for my X, Y and M data that I used in the below command:

[C1, h1] = m_contourf (X, Y, M, [1, 1]);

[Bjorn Gustavsson]

OK, it seems that all the nans in M makes things go kaboom.

This solves most of the problems:

M(~isfinite(M(:))) = 0;
M(1,:) = 0;
M(:,1) = 0;
M(:,end) = 0;
M(end,:) = 0;  
[C1,C2] = contourf(X,Y,M,[1 1]);
i1 = 1;
hold on
while i1 < size(C1,2)
  i2 = C1(2,i1);
  i1 = i1+1;
  fill(C1(1,i1:(i1+i2-1)),C1(2,i1:(i1+i2-1)),[0.7 0.7 0.7])
  i1 = i2+i1;
end

This leaves you with all interior waters filled in as well. Maybe you can "handle that later".

The fill-function also handles holes, provided that the orientation around the outer and inner edges are oposite, but when I tried to use that trick on the C1-array "it didn't turn out ideal":

[C1,C2] = contourf(X,Y,M,[1 1],'r');
xC = [];
yC = [];
i1 = 1;
while i1 < size(C1,2)
  i2 = C1(2,i1);
  i1 = i1+1;
  xC = [xC,C1(1,i1:(i1+i2-1))];
  yC = [yC,C1(2,i1:(i1+i2-1))];
  i1 = i2+i1;
end
fill(xC,yC,[0.7 0.7 0.7])

Perhaps you can use parts of this.

[Leon]

Working now! Thank you so much.

[Bjorn Gustavsson]

My pleasure.