Probably my explanation is not good, I need following kind of graphs. Matlab, sigmaplot solution will be welcomed. Graphpad Prism may also be an option.
The x-axis is splitted, actually 2 data sets (same x-axis but different y-axis). it is error plot (mean I also need error bars)
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I'm using GUIDE to display a plot within an axis that contains two data sets: the original signal and the average of the signal, but for some reason it seems to only plot one.
The axis is designated as m_graph and the data sets are avg and signal, which both share time.
plot(handles.m_graph, time,signal)
hold on
plot(handles.m_graph, time, avg)
When I compile the program, only the average is plotted. It seems to skip over the original signal or reset the axis. I've tried plotting just the signal so I know the data is fine.
I feel like I am missing something, maybe the set function?
Sorry my reasoning was a bit wrong; it applies to the current selected axes (it does not parent to the Figure).
However, using axes(h) followed by hold on or just hold(h,'on') will either switch the focus to the axes then turn hold on or turn hold on for a specified axes, respectively.
I have 8 plots which I want to implement in my Matlab code. These plots originate from several research papers, hence, I need to digitize them first in order to be able to use them.
An example of a plot is shown below:
This is basically a surface plot with three different variables. I know how to digitize a regular plot with just X and Y coordinates. However, how would one digitize a graph like this? I am quite unsure, hence, the question.
Also, If I would be able to obtain the data from this plot. How would you be able to utilize it in your code? Maybe with some interpolation and extrapolation between the given data points?
Any tips regarding this topic are welcome.
Thanks in advance
Here is what I would suggest:
Read the image in Matlab using imread.
Manually find the pixel position of the left bottom corner and the upper right corner
Using these pixels values and the real numerical value, it is simple to determine the x and y value of every pixel. I suggest you use meshgrid.
Knowing that the curves are in black, then remove every non-black pixel from the image, which leaves you only with the curves and the numbers.
Then use the function bwareaopen to remove the small objects (the numbers). Don't forget to invert the image to remove the black instead of the white.
Finally, by using point #3 and the result of point #6, you can manually extract the data of the graph. It won't be easy, but it will be feasible.
You will need the data for the three variables in order to create a plot in Matlab, which you can get either from the previous research or by estimating and interpolating values from the plot. Once you get the data though, there are two functions that you can use to make surface plots, surface and surf, surf is pretty much the same as surface but includes shading.
For interpolation and extrapolation it sounds like you might want to check out 2D interpolation, interp2. The interp2 function can also do extrapolation as well.
You should read the documentation for these functions and then post back with specific problems if you have any.
I would really appreciate some help.
I have to independent datasets. Each dataset contains two variables: dates (as datenumber) and corresponding data. I need to plot both datasets on one scatter plot with dates on x-axis and two y-axes. I have been trying with the following code:
figure(1);
scatter(x1,y1,'g');
set(gca);
ax1=gca;
set(ax1,'YColor','g');
ax2 = axes('Position',get(gca,'Position'),'YAxisLocation','right', XTick'[],'Color','none','YColor','r');
hold on; scatter(x2,y2,'r');
Now, this gives correct y-axis on the right side, however on the right side I end up with two overlapping y-axes.
Also, I need to change x-axis so that it displays dates as opposed to datenumbers. I've tried to incorporate datetick into the code but it again gives me two overlapping x-axes.
Does anyone know how to go about it?
thank you
I tried your script with your sample input and found no problems. Anyway, here's a solution which uses the matlab function plotyy, which is suited to simple plots like this:
%generate input
x1=[732490 732509 732512 732513 732521 732528];
y1=[7.828 7.609 22.422 14.758 26.258 1.477];
x2=[732402 732403 732404 732404 732433];
y2=[0.693 0.645 0.668 0.669 0.668];
figure(1);
[ax, h1,h2]=plotyy(x1,y1,x2,y2,'scatter');
%set colors manually
green=[0 1 0];
red=[1 0 0];
set(h1,'cdata',green);
set(h2,'cdata',red);
set(ax(1),'ycolor',green);
set(ax(2),'ycolor',red);
%note the 'keepticks' and 'keeplimits' options
datetick(ax(1),'x','yyyy-mm-dd','keepticks','keeplimits');
datetick(ax(2),'x','yyyy-mm-dd','keepticks','keeplimits');
Without the datetick call the plotyy function synchronizes the xticks in the plot. When you call datetick, it recalculates the ticks, unless you explicitly tell it not to, see the option keepticks, and this is seen as two sets of x axes (even though the x coordinates are the same, the ticks are located at different positions). The keeplimits option is needed to preserve the original xlim. It obviously needs some more manual work to get plots like this sufficiently pretty.
Also note that I set the axes and data colors manually: there might be a way to do this more elegantly.
Update: keeplimits originally missing
Update2: changed sample data to correspond to updated question comment
The MATLAB surf plot below is essentially two plots plotted adjacent to each other. For clarity, I have included some code below used to prepare the plot:
band1 = horzcat(band1, eSurface2(:,:,1));
band2 = horzcat(band2, eSurface2(:,:,2));
surf(band2,'DisplayName','band2');
surf(band3,'DisplayName','band2');
I would like for the y axis numbering to restart at the start of the second graph. How do I go about doing that?
You can use the 'YTick' and 'YTickLabel' properties of the axis to control the ticks, this way you can make it start from zero for the second graph. It will require some trail and error to get it right. See the relevant doc here (you'll have to scroll all the way to the bottom of the page).
Take advantage of the following feature of 'YTickLabel': "If you do not specify enough text labels for all the tick marks, MATLAB uses all of the labels specified, then reuses the specified labels".
So basically, the graph labeled "Thermal Wind" has an extreme value that compresses the y-values for all the other plots, making it much harder to see any of the individual variations in the other plots. Is there a way to neatly cut off this extreme value? I could just rescale the y limit to a maximum of 40, but then this looks ugly.
As for the alternative I've tried - it's here:
I would recommend trying to plot it on a log scale. The function you'll want to consider using is semilogx, though for completeness I recommend also reading the help file on loglog.
Alternately, you could use subplot to generate multiple plots, one of which is zoomed into a region of interest.
Are the outlier points errors in the data, or do they represent extreme cases?
If they are not valid data, just manually exclude them from the data, plot the graph, and include a text clarification when describing the graph. If they are valid data, then trimming them would misrepresent the data, which isn't a good thing.
Graphs of data aren't art: their main goal isn't to be pretty; it's to provide a useful visualization of data. There are some minimum requirements on appearance, however: the axes have to be labeled, the units have to be meaningful, the different curves have to be visually distinct, etc. As long as your graph has these things, you shouldn't expect to lose marks for presentation.
There are two approaches that I use:
One approach would be transform the data so it will fill the plot nicely. Make the transform so that it wouldn't touch the range - say -10 to +10. In your case you could choose it so that 100 transforms to +15 and -100 to -15.
For clarity you need to then also set and label the y ticks appropriately. And for nice style make sure the line changes slope when it goes over the border.
I plot the data as is. But set the axis limits say from -10 to +10. Where points lay outside I place upwards and downwards triangles along the border to mark in which direction the "outliers" would be. Obviously this is only good when there aren't too many.