For- loop to plot multiple images on a figure

Question

BN 2020-4-14

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/517891-for-loop-to-plot-multiple-images-on-a-figure

评论： Geoff Hayes 2020-4-14

采纳的回答： Geoff Hayes

coordinates.mat

在 MATLAB Online 中打开

Hello,

I have 6 images that I want to insert on the one plot at the same time based on the latitude and longitude that specified in a table (namely coordinate). All 6 pictures name like this: filename1.png, filename2.png, filename3.png, ... filename6.png; Which should plot using the information in the coordinate table first, second, third ..., and sixth respectively.

I know how to plot one by one them using this code:

% This code for plot just first image
LowerLeftCornerLon = coordinates.LowerLeftCornerLon(1); % the first image uses the first row of the table, second must use second and so on
UperrRightCornerLon = coordinates.UperrRightCornerLon(1);
LowerLeftCornerLat = coordinates.LowerLeftCornerLat(1);
UperrRightCornerLat = coordinates.UperrRightCornerLat(1);
img1_lon = [LowerLeftCornerLon,UperrRightCornerLon];
img1_lat = [LowerLeftCornerLat,UperrRightCornerLat];
[c, ~, tr] = imread('img1.png');
im = image (img1_lon,img1_lat,flipud(c));
im.AlphaData = tr;
% then use hold on and do the same thing for the second picture but this time reading the second row of coordinate table

But I have some problems with writing a loop in order to plot all of them automatically.

Here is my try:

hold on % plot pictures on the previous plot
% first read all images from dir
if true
   srcFiles = dir('F:\university\matlab\mypictures\*.png'); 
   for i = 1 : length(srcFiles)
       filename = strcat('F:\university\matlab\mypictures\',srcFiles(i).name);
       IMAGES{i} = (filename);
  end
end
for i=1:numel(IMAGES)
    img_lowlat(i) = coordinates.LowerLeftCornerLat(i);
    img_lowlon(i) = coordinates.LowerLeftCornerLon(i);
    img_uplat(i) = coordinates.UperrRightCornerLat(i);
    img_uplon(i) = coordinates.UperrRightCornerLon(i);
    
    img_lon(i) = [img_lowlon(i),img_uplon(i)];
    img_lat(i) = [img_lowlat(i),img_uplat(i)];
    
    hold on
    [c, ~, tr] = imread('IMAGES{i}');
    im = image (img1_lon,img1_lat,flipud(c));
    im.AlphaData = tr;
end

But this not accomplished well and after that, I get this error:

Unable to perform assignment because the indices on the left side are not
compatible with the size of the right side.

Did you know how can I do to fix my for loop and plot all images on the same plot successfully?

Really thank you

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BN 2020-4-14

Dear Geoff Hayes,

Thank you so much, it is fixed now and worked very well. I'll click on accept the answer if you post it as an answer.

It is really helpful. Thanks again

Best Regards

Geoff Hayes 2020-4-14

Glad to have been able to help, Behzad!

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Answer 1

Geoff Hayes 2020-4-14

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/517891-for-loop-to-plot-multiple-images-on-a-figure#answer_426081

在 MATLAB Online 中打开

The original error was concerned with

img_lon(i) = [img_lowlon(i),img_uplon(i)];
img_lat(i) = [img_lowlat(i),img_uplat(i)];

where a two-element array (right-hand side) was being assigned to a scalar on the left-hand side. This was replaced with

img_lon = [img_lowlon(i),img_uplon(i)];
img_lat = [img_lowlat(i),img_uplat(i)];
hold on
[c, ~, tr] = imread(IMAGES{i});
im = image (img_lon,img_lat,flipud(c));