Inside the MATLAB Desktop
November 1st, 2007
Adding annotations to graphs
Once you’ve analyzed and plotted your data or results, the next step is often to add the plot to a report or a paper as a document. In many cases you will need to add explanation and annotations to the data to explain its salient features to the reader of your document. The Figure Palette (one of the Plot Tools) let’s you do this by adding and configuring annotations such as arrows, text boxes, and shapes directly to the data in your plot.
To get started, plot your data and open the Figure Palette from the Figure View menu.
Now, suppose you want to mark the first point of inflection of the plot and add a comment explaining its meaning. Click on the Text Arrow item in the Annotations section of the Figure Palette (shown on the left), then click on the plot to position the base of the arrow and drag & release to position its head. A cursor at the base of the arrow will show you where to enter text.
Once the text is entered you can move the arrow and change its orientation by using the positioning handles at the beginning and end of the arrows.
Other arrows and shapes can convey additional information. Suppose you wanted to add a text box explaining the second inflection point and an arrow indicating the time interval between the two inflection points: this could accomplished by copying and pasting the first text arrow and adding a double arrow annotation for time interval. If you wanted to label the double arrow you could use a text box:
By default the text box has a black border. You can remove this by double clicking it to open the Property Editor and setting its Line Style to “none”.
Clicking on the double arrow enables you to modify its color and size properties to get the right look.
You can also add lines to draw attention to the left and right extent of the double arrow.
Once you are finished, you can close the Plot Tools and copy the figure to your document.
The annotations that you have added and edited have treated the figure very much as a document, combining representations of data with conceptual content (the annotations). Consequently, you may want to save your work product as it evolves. This can be done by saving it as a “.fig” file using the figure “File” menu or the MATLAB “hgsave” function. Saved figures can then be restored using the figure “File” menu or the MATLAB command “hgload”.
By
James Owen
James is a developer on the Data Tools team, working mainly in the area of Data Exploration. He is a connoisseur of brand-name American beer.
4:16 pm |
Posted in Data Tools |
Permalink |
You can follow any responses to this entry through the RSS 2.0 feed.
You can skip to the end and leave a response. Pinging is currently not allowed.
Leave a Reply
|
It will be extremely handy to have a “mouse-over data tip”. Often, it’s too much clutter to display text annotations for each point in a matlab plot. Instead, it would be nice to simply mouse over (or click) on a data point to see its text annotation. What do you think?
Hi Hao,
You can currently click a point within a figure and see a tool-tip style window containing the selected point. Select the “Data Cursor” tool in the figure window, and subsequently click a point within your figure.
-Ken
Yes, a “tooltip” for data will be nice.
I see a way of customizing data cursor text.
http://www.mathworks.com/access/helpdesk/help/techdoc/index.html?/access/helpdesk/help/techdoc/ref/datacursormode.html&http://www.google.com/search?q=data+cursor+matlab&sourceid=navclient-ff&ie=UTF-8&rlz=1B3GGGL_enUS240US240
but it seems too cumbersome for attaching short descriptions to scatter points in a plot.
Ideally,
>> pts = [0.1 0.2; 0.3 0.4; 0.1 0.3];
>> desc = {’case abc’; ‘case xyz’; ‘case def’};
>> h = plot(pts(:,1), pts(:,2), ‘o’);
>> datatooltip (h, desc)
and you move a mouse over the data point (or click on it) to see the “desc” string. How’s that?
Hi Hao,
I see what your driving at (I think) - you want to be able to toggle the annotations when you click them (or maybe have them popup when you mouse over them).
I’ll forward along your request!
-Ken
I think what Hao is requesting is something just like the ‘TooltipString’ property on uicontrols and the built in tool tips that pop-up when you mouse over the figure toolbar buttons. I’d like to second that request. Is it possible to add a ‘TooltipString’ property to graphics objects such as lines, patches, surfaces, etc.? And maybe even a ‘MouseHoverFcn’ property that defines a function to call when the mouse is hovered over the object. This is just like the existing ButtonDownFcn property but wouldn’t require a mouse click. (The MouseHoverFcn would just allow more end user customization over a simple tooltip display.)
Hi Tim,
I agree…that sounds like a useful feature. I’ve forwarded your request on to the appropriate team.
Thanks for the great feedback,
-Ken
James,
I like using the annotation, but I often find that when I copy the plot and paste it into a document, the arrows and text have changed location and/or size in the pasted version. Sometime, I manually shift things around to get them to line up in the correct spot, but usually I give up on annotating them in Matlab and wait until I am in Word or PowerPoint to do the annotation. However, I would really like to be able to do the annotation in Matlab since it is much more intuitive.
How can I get around these resizing and repositioning problems?
Pat,
Without knowing the details of your issue, I would say go to copy options and try using the “match screen size” and “bitmap” options before copying.
If that does not help, and you have a license with software maintenance, you should contact technical support (with the same “request a feature” link on the right sidebar) or if not, ping the community on comp.soft-sys.matlab (MATLAB newsgroup link on the top navigation bar).