How to use strcat in imwrite to save multiple figures

Question

Kelsey Ward 2023-10-24

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2038081-how-to-use-strcat-in-imwrite-to-save-multiple-figures

评论： Walter Roberson 2023-10-25

在 MATLAB Online 中打开

I am trying to save figures in a loop using strcat and imwrite but I get the following error:

Error using imwrite (line 442)

Expected DATA to be one of these types:

double, single, uint8, uint16, uint32, uint64, int8, int16, int32, int64,

logical

Instead its type was matlab.graphics.chart.primitive.Line.

This is a subset of the code I am using to make the figures:

nfile = 'filename.nc';
z = [];
T = [];
L = [];
for j = 5:60;
    nfile = strcat('folder_location/40f17_',num2str(j,'%02d'),'_1.nc');
    z  = ncread(nfile, 'z');
    T  = ncread(nfile, 'T');
    L  = ncread(nfile, 'L');
    
    MeansL = mean(L,'omitnan');
    MeansT = mean(T,'omitnan');
    MeansZ = mean(z,'omitnan');
    
    n_L = length(MeansL);
    n_T = length(MeansT);
    n_z = length(MeansZ);
    time_L = 1:n_L;
    time_T = 1:n_T;
    time_z = 1:n_z;
    
    plotL = plot(time_L,MeansL);
    imwrite(plotL,strcat('folder_location/L40f17_',num2str(j,'%02d'),'.png'));
    
    plotT = plot(time_T,MeansT);
    imwrite(plotT,strcat('folder_location/T40f17_',num2str(j,'%02d'),'.png'));
    
    plotZ = plot(time_z,MeansZ);
    imwrite(plotZ,strcat('folder_location/z40f17_',num2str(j,'%02d'),'.png'));
end

It's just simple line graphs that I am trying to save directly as png files.

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Answer 1

Walter Roberson 2023-10-24

0
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2038081-how-to-use-strcat-in-imwrite-to-save-multiple-figures#answer_1339766

See exportgraphics()

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DGM 2023-10-25

编辑：DGM 2023-10-25

在 MATLAB Online 中打开

You might be taking my earlier advice a little too severely. My point was to discourage using figure capture when your inputs are strictly raster images. When you're trying to capture graphics objects (line plots, charts, etc), it's appropriate to use exportgraphics(), saveas(), etc.

exportgraphics(gca,'myfilename.png') % just the axes

or

exportgraphics(gcf,'myfilename.png') % the figure

Walter Roberson 2023-10-25

在 MATLAB Online 中打开

nfile = 'filename.nc';
z = [];
T = [];
L = [];
ax = gca;
for j = 5:60;
    nfile = strcat('folder_location/40f17_',num2str(j,'%02d'),'_1.nc');
    z  = ncread(nfile, 'z');
    T  = ncread(nfile, 'T');
    L  = ncread(nfile, 'L');
    
    MeansL = mean(L,'omitnan');
    MeansT = mean(T,'omitnan');
    MeansZ = mean(z,'omitnan');
    
    n_L = length(MeansL);
    n_T = length(MeansT);
    n_z = length(MeansZ);
    time_L = 1:n_L;
    time_T = 1:n_T;
    time_z = 1:n_z;
    
    plot(ax, time_L,MeansL);
    exportgraphics(ax,strcat('folder_location/L40f17_',num2str(j,'%02d'),'.png'));
    
    plot(ax, time_T,MeansT);
    exportgraphics(ax, plotT,strcat('folder_location/T40f17_',num2str(j,'%02d'),'.png'));
    
    plot(ax, time_z,MeansZ);
    exportgraphics(ax, plotZ,strcat('folder_location/z40f17_',num2str(j,'%02d'),'.png'));
end