Extract X,Y data from scatter plot (2024)

Hi,

When I run the first code, s doesn't have any properties or values associated. It says 0x0 GraphicsPlaceholder.

Also, when I run the second and third codes you provided, I get these messages from MATLAB.

'unrecognized method, property, or field 'XData' for class 'matlab.graphics.GraphicsPlaceholder'

'unrecognized method, property, or field 'YData' for class 'matlab.graphics.GraphicsPlaceholder'

I feel like we're missing some details. Did you have the figure window open when you ran the code? Is your figure created using the scatter function or did you use plot? I assumed scatter. Here's a full working example using plot.

You could do something similar if your plot was created using scatter

Of course, if you are creating the plot yourself, this could be simplified using a handle.

Of course, if the point is to capture the x and y values, it would make more sense to do this.

Because it is a semilog plot, so I don't use scatter or plot. Here I used

semilogx(saproduct,laplacian,'k.','markersize',8);

saproduct and laplacian are two matrix containing values of 756x519 single.

They contain huge numbers

Now we're getting somewhere! When passed matrices, MATLAB will plot each column as its own series. That means your semilogx plot is made up of 519 data series with 756 data pairs in each one. Since you are setting your marker color, you probably noticed that (each series is assigned a different color). To extract the data from the figure, you would have to loop through each line object, combining the data as you go.

Luckily, since you have the data and are creating the plot, we don't have to do that. We can use linear indexing instead to create the exact same semilogx plot, but with all the data in a single series. This makes it easier to figure out the [X,Y] pairing. Linear indexing turns both matrices into column vectors by stacking the columns on top of each other (column 2 is directly under column 1, etc).

X and Y are vectors with size 392364 x 1.