MATLAB: How to draw contour on the other two planes when using SURFC

contoursliceMATLABotherplaneprojectionslicesurfx-zxzy-zyz

I use SURFC to plot my data(eg. peaks(30)) and the contour on xy plane looks great for knowing the maximum and minimum at some levels. But I also want to have contours on yz plane and zx plane. Is it possible to do that?

Best Answer

The CONTOURSLICE may be an easy way to achieve this when you have the volume data for your surface plot. But if there's no volume data, it'll get more complex to do that. You'll do CONTOUR for each plane by changing the order of the input arguments and then swapping corresponding x/y/zdata of each contour line to achieve the effect. Please refer to the following example.

[X,Y,Z] = peaks(30);
h1=surfc(X,Y,Z);
xmin=-3;xmax=3;ymin=-3;ymax=3;zmin=-10;zmax=10;
axis([xmin xmax ymin ymax zmin zmax]) 
hold on;
%%contour on yz plane
[C,h]=contour(Y,Z,X);
hpatch = get(h,'Children');
for i = 1:length(hpatch)
      ch = hpatch(i);
      xdata = get(ch,'Xdata'); %

      ydata = get(ch,'Ydata');
      set(ch,'Xdata',zeros(size(xdata))+xmax);
      set(ch,'Zdata',ydata);
      set(ch,'Ydata',xdata);
end
%%contour on xz plane
[C,h]=contour(X,Z,Y);
hpatch = get(h,'Children');
for i = 1:length(hpatch)
      ch = hpatch(i);
      xdata = get(ch,'Xdata'); %
      ydata = get(ch,'Ydata');
      set(ch,'Ydata',zeros(size(ydata))+ymax);
      set(ch,'Zdata',ydata);
      set(ch,'Xdata',xdata);
end

For scatter data, you could also refer to related solution below "Is it possible to draw contour on YZ and ZX planes?".

Related Solutions

MATLAB: Extract XData and YData from contourm hggroup handle

Do you want to extract the latitude and longitude values, or the projected X/Y coordinates?

If the former, the coordinates are in the SC matrix in your example. Its format is a bit obscure, so I use a slightly-modified version of this contourcs function to extract it.

Below is an example that I wrote a while ago that I think does the exact thing you're attempting (masking a contour plot to show within a polygon only).

If you really want x/y coordinates, then you'll need to add

for ii = 1:length(Cout)
  [Cout(ii).X2, Cout(ii).Y2] = mfwdtran(Cout(ii).Y, Cout(ii).X);
end

after you extract the contours.

------------

The full example:

    % Load coastlines (replace with your polygon)
    latlim = [23 50];
    lonlim = [-127 -65];
    Usa = shaperead('landareas', 'usegeo', true, 'bounding', [lonlim' latlim']);
    [latusa, lonusa] = maptrimp(Usa(1).Lat, Usa(1).Lon, latlim, lonlim);
    % Create contours (replace with your gridded data)
    n = 50;
    xdata = linspace(lonlim(1), lonlim(2), n);
    ydata = linspace(latlim(1), latlim(2), n);
    zdata = peaks(n);
    figure;
    usamap('conus');
    plotm(latusa, lonusa, 'k');
    [C,h] = contourm(ydata, xdata, zdata);
    % contourcs-stolen code
    K = 0;
    n0 = 1;
    while n0<=size(C,2)
       K = K + 1;
       n0 = n0 + C(2,n0) + 1;
    end
    el = cell(K,1);
    Cout = struct('Level',el,'Length',el,'X',el,'Y',el);
    n0 = 1;
    for k = 1:K
       Cout(k).Level = C(1,n0);
       idx = (n0+1):(n0+C(2,n0));
       Cout(k).Length = C(2,n0);
       Cout(k).X = C(1,idx);
       Cout(k).Y = C(2,idx);
       n0 = idx(end) + 1; % next starting index
    end
    % Trim to coastlines
    [xc, yc] = deal(cell(length(Cout),1));
    for ii = 1:length(Cout)
        [xc{ii}, yc{ii}] = polybool('&', Cout(ii).X, Cout(ii).Y, lonusa, latusa);
    end
     % Plot
    figure;
    usamap('conus');
    plotm(latusa, lonusa, 'k');
    cellfun(@(x,y) plotm(y,x,'r'), xc, yc);

MATLAB: How to extract surface plot data from MATLAB figure

[X,Y,Z] = peaks(100) ;
surf(X,Y,Z)
h = gcf; %current figure handle
axesObjs = get(h, 'Children');  %axes handles
dataObjs = get(axesObjs, 'Children'); %handles to low-level graphics objects in axes
%%get data 
XX = dataObjs.XData ;
YY = dataObjs.YData ;
ZZ = dataObjs.ZData ;

Best Answer

Related Solutions

MATLAB: Extract XData and YData from contourm hggroup handle

MATLAB: How to extract surface plot data from MATLAB figure

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