Magnifying a Segment of Plot in MATLAB PATCH-Figure

Hi,

I tried to create a magnified part of a PATCH figure but unfortunately, I couldn't find any options for how to make it, like on the image below. I know that there are options for how to magnify a part of a regular plot(x,y) figure, but with PATCH I have no idea.

There is an example below of a PATCH used Figure and I want to magnify some part of this.

Do you have any idea how can I make it?

Thank you so much for your helpful comments!

Answer 1

[akshatsood]

Hi Kovacs,

I understand that you want to magnify a segment of plot in MATLAB patch figure. I have considered the following patch plot for the rest of the answer whose implementation in MATLAB is as follows. I have annotated the desired region with a red rectangle.

% assuming a sample data for plotting patch

x = [2; 4; 6];
y = [4; 5; 4];
c = [0; 6; 4];

figure
patch(x,y,c) % create a patch plot

% red rectangle indicates the segment to be magnified

rectangle('Position',[3 4.4 1 0.4],'EdgeColor','r','LineWidth',2);

colorbar

Method 1: specifying the axes limits using xlim and ylim to zoom into the desired region

In this method, you tweak the limits of the x and y axis to extract the desired portion from the figure. Additionaly, you can leverage daspect function to control data unit length along each axis. It should be noted that, this method overwrites the original plot in the figure and illustrates only the zoomed segment. Here is the code snippet to implement the method.

zoomedInRegion = ([3 4 4.4 4.8]); % area of interest

% modifying the x and y limits

xlim(zoomedInRegion(1:2));
ylim(zoomedInRegion(3:4));

daspect('auto'); % adjust the aspect ratio of axis if required

Method 2: creating a new axis in the same figure to represent the zoomed segment

In case you wish to wish to observe the original plot as well as the zoomed segment on the same figure, you can create a new axes on the same figure and position it accordingly. Now you can utilise copyobj and findobj functions to recreate the patch plot on the new axis. Further, adjust the x and y limits to zoom into the desired region. Here is the code snippet for your reference

axNew = axes('Position',[.7 .7 .2 .2]); % creating a new axes and positioning it

copyobj(findobj('Type', 'patch'), axNew); % copying the patch plot to new axes

% adjuisting x and y limits to zoom into the suitable area

zoomedInRegion = ([3 4 4.4 4.8]); % area of interest

% modifying the x and y limits for the new axes

axNew.XLim = zoomedInRegion(1:2);
axNew.YLim = zoomedInRegion(3:4); 

annotation('textarrow',[.52 .64],[.64 .8]) % adding arrow annotation

Apart from the methods mentioned above, have a look at following tools on File Exchange

magnify - File Exchange - MATLAB Central (mathworks.com)

Create Magnified Plot of Rectangular ROI on Same Figure - File Exchange - MATLAB Central (mathworks.com)

On-figure magnifier - File Exchange - MATLAB Central (mathworks.com)

I hope this helps.

[Kovacs Mario]

It is helpful!

Thank you so much! :)