Editor's Note: Popular File 2018
GRABIT Extracts data points from an image file.
GRABIT starts a GUI program for extracting data from an image file. It is capable of reading in BMP, JPG, TIF, GIF, and PNG files (anything that is readable by IMREAD). Multiple data sets can be extracted from a single image file, and the data is saved as an n-by-2 matrix variable in the workspace. It can also be renamed and saved as a MAT file.
Following steps should be taken:
1. Load the image file.
2. Calibrate axes dimensions. You will be prompted to select 4 points on the image.
3. Grab points by clicking on points. Right-click to delete a point. Image can be zoomed during this stage.
4. Multiple data sets will remain in memory so long as the GUI is open. Variables can be renamed, saved to file, or edited in Array Editor.
Panning is achieved by clicking and dragging on the image. In addition to using the zoom button, there are keyboard shortcuts for zooming:
<shift> - center view
<a> - zoom in
<b> - zoom out
<space> - reset view
This code will also work for extracting data points from a tilted or a skewed image (even upside-down or mirrored). The calibration stage ensures that the imperfect orientation or quality of the image is accounted for.
The types of files that will most likely work are BMP, JPG, TIF, GIF (up to 8-bit), and PNG files. Basically, any format supported by the IMREAD is accepted.
GRABIT(FILENAME) will start the GUI program and open the image file FILENAME.
Type GRABIT('-sample') to load a sample image.
Created in MATLAB® R13. Tested up to R2006a
Cite As
jiro (2021). GRABIT (https://www.mathworks.com/matlabcentral/fileexchange/7173-grabit), MATLAB Central File Exchange. Retrieved .
Comments and Ratings (257)
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Acknowledgements
Inspired: GRABIT - POLYFIT, INTERACTIVEMOUSE, SMIProm
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GREAT GREAT GREAT WORK!!!!
this really works, esp. for simple small plots, thanks
Worked great! My only suggestion for improvement would be to retain the calibration points as a data set.
Easy to use, but doesn't work with log scale.
Brilliant!. I really hope this can be updated so that it's compatible with the newer versions
This is an indispensable tool, however I worry about the warning messages I'm seeing when used in 2019b. I see that the last update was done many years ago - I wonder if the community could make the update and then upload a new version here. Or perhaps on github...
For example:
Warning: The DrawMode property will be removed in a
future release. Use the SortMethod property instead.
> In grabit (line 514)
Warning: The EraseMode property is no longer supported
and will error in a future release.
> In grabit>loadImageFcn (line 879)
Warning: The DrawMode property will be removed in a
future release. Use the SortMethod property instead.
> In grabit>loadImageFcn (line 884)
Warning: Setting the "KeyPressFcn" property is not
permitted while this mode is active.
> In matlab.uitools.internal.uimodemanager>localModeWarn (line 226)
In matlab.uitools.internal.uimodemanager>@(obj,evd)(localModeWarn(obj,evd,hThis)) (line 94)
In grabit>zoomBtnFcn (line 1278)
wonderful
Great tool, but does not work with log scales....
very simple to use!!
manual point grabbing is something you can do in excel by setting the picture in background, very good looking tool, little use to me
Very good
Does not work with 2018b or 2019a. At the step "Click on ORIGIN of x-axis" the GUI will not accept any inputs, or proceed to the next step in calibration.
Works like a charm. Really helped me a lot. I may even use this in my thesis works since I work with many different uncommon graphs that it is hard to get formulations or informations about. But I don't know if it would be " right " in terms of scientific work.
Love it, thanks
Easy to use. Works well.
Wonderfully simple and straightforward.
Work perfect. Thanks so much!
Very comfortable in using. Thanks
saves a lot of time
Very convenient. Thanks!
Very good! I have tried with different softwares and the results from grabit agree very well, thought more easy.
Fantastic. Really streamlines the process of digitizing and saving plots from published papers. Thanks Jiro!
Very useful
brilliant!
Nicely done!
Not working :(
I loaded the JPG, when I run GRABIT with my filename, it shows me nothing.
I'm using 2018b.
Please do suggest me.
Great, exactly what I needed.
Very beautiful.
very good for linear. drawing a plot based on log scale picture is a bit tricky. What i did was i plotted and got the values for my graph. For those values, I had to times it by 10^-2 and used loglog to remake a very similar graph compared to the scanned copy. Otherwise, amazing work.
Nicely done!
good
I forgot to give *****
And never mind the log scale question; using this tool and picking points with respect to power of 10 will give log scale powers. Then plotting those values as 10^picked points should give the log scale data if I am not wrong!
Can you add a capability to do the same thing in log scales?
Great program. Simple and works well. Indeed log scales might come in handy, although not essential.
Very very good! Thanks.
Really great work. Plz, resolve some common issues like semilog,log-log axes. Some error on the draw now "Warning: The DrawMode property will be removed in a future release. Use the SortMethod property instead. " can also be resolved.
Many thanks in advance.
Brilliant thanks
Very useful. Thank you jiro.
Very useful, thanks for the work!
Amazing!
it's brilliant
Amazing script!
Simply brilliant! Thank you!
Thank you so much for that awesome tool. I've used it plenty of times over the years. Keep up the good work!
A perfect tool! Thanks!
Excellent code. FTI for those struggling with Drawmode, Erasemode deprecation.
Replace:
'drawmode' . , 'fast', ...
WITH
'SortMethod' , 'depth', ...
and delete 'Erasemode', 'normal'
Your code should work fine in newer versions of MatLab, if those are the only issues.
Which is the latest version of MATLAB for GRABIT command to work. Anyone?
For those who want to grab datapoints from a log-log graph, you can apply a simple transformation. For calibration, select points that are integer decades apart, then specify the decade (ex 3x10^1 -> 1, 3x10^4 -> 4) for the calibration values.
Once the data is grabbed, just apply the following transformation: [x, y] -> [constant1*10.^x, constant2*10.^y]. For example, where one axis limits are from 3x10^1 to 3x10^4, then the constant is 3. One such transformation can be executed as the following: a1 = [3*10.^Data001(:,1) 10.^Data001(:,2)];
Not supporte by R2017a :-(
Great Functions!
Great utility! Thanks!
An extremely useful tool! Thanks!
does it work for double Y axes?
Is it possible to use it when one axis is in log scale and not linear?
Really great tool. I would suggest to build in an interpolation as a post processing option.
Great tool to extrapolate raw data from stress-strain curve images. Thanks for a great macro Jiro!
good
How to make this understand that an axis is on log scale
Effective tool. Useful with stress-strain curves
Perfect
Great tool.. Thank you
How can I use it for log log plot?
Very useful function,
this code is pretty useful to get the x and y pixels of any jpeg image (or any other types of images). However, if I have a jpeg thermal image and I need to extract the temperature data from it, i.e., the value beneath each point (xpixel,ypixel), this code is not useful.
P.S: ginput function in MATLAB does, to some extent, the same job as this code.
It's great.Thanks the author.
When I grab a point, the function draws a red dot on the image.
Is there a way to change the color of the dot from red to another color, for instance cyan, even by modifing the function? Thanks
Great tool.
How to extract the data points if the one of the axis is in logscale? For e.g. yaxis in log scale.
good
Great GUI. If you could set it for a semilogy, semilogx, or loglog instead of linear only, that would be incredible. Also, the cursor accuracy when grabbing data points be improved by making it more like the cursor when selecting the X, Y axes.
Thank U so much!
I like the interface and resolution allowed by the algorithm. However, when I tried using on a plot, it consistently is not correctly scaling my "grabbed" points to neither the min-max x or y coordinates that I input.
Thx for this file!
excellent tool!
thank you so much!
good
Error message, unable to expand "grabit.zip" into downloads. Any solutions for this issue yet ?
There is an error message when attempting to unzip the file:
"Unable to expand "grabit.zip" into "Downloads".
(Error 1 - Operation not permitted.)"
Just wanted to notify --
It seems quite useful, but on OSX 10.11.6, Version R2016a, it warns me of 2 deprecated properties which "may go away in future releases." (DrawMode and EraseMode) So it looks like it needs an update. If I can I may try to update this as it might be a good chance for learning some new things for me.
I found that it's a little tricky to set up the axes as the cursor is quite fine, but that is an advantage really. One needs to be careful and practice a bit. Also Log plots need you to choose the exponent so again a tad tricky but practice should help. Not obvious how else you could do it. And "max" really does mena the maximum value on the scale.
How we can save the image, after garbing points.
is there any way to get the selected image.
great tool!
Thank you for this!
this is a very use full application,
Thank you
It is really a amazing GUI,but there is a warning, EraserMode will not be supported.so it should be updated.
Really easy and straightforward to use. No unnecessary complications or extra features. Works great!
I use this all of the time for analyzing data from others' work. I wish there was a function to deal with log axes.
Just what the doctor ordered, worked well first time. Thank you Jiro!
Paul
It worked well and helped me a lot. Thanks!
Great software, it was a little dated so I needed to tweak it a bit to deal with log scale axis and get rid of those annoying warnings.
like
Very useful software! Very intuitive and easy to use. Exactly what I needed.
very good software, so much thanks!
Excellent. Thanks a lot.
Great work! Very useful
Very useful code. This is what I was looking for. Thanks
This has been a great utility for me over the years. However, it appears to be showing its age with the new graphics system. I am now seeing the following warnings when starting the tool:
Warning: The DrawMode property will be removed in a future release. Use the SortMethod property instead.
> In grabit (line 471)
Warning: The EraseMode property is no longer supported and will error in a future release. Use the ANIMATEDLINE function for animating lines
and points instead of EraseMode 'none'. Removing instances of EraseMode set to 'normal', 'xor', and 'background' has minimal impact.
Exactly what I needed. The only thing that was not intuitive to me was hitting [ENTER] to indicate that I was done specifying each axis.
PERFECT
Straight-forward, simple, and gave me everything I was looking for, and much more.
- Upload image file
- Choose/define X,Y axes
- Zoom/Pan to area of interest
- Click to record desired datapoints
- Plot is generated in real-time
- Data table can be saved for further processing!
Worked well for simple data point extraction from a PNG.
For those of you getting the error "unexpected matlab operator", make sure you call "addpath" and add the directory in which this .m file is stored. The main function calls other functions within the .m file.
amazing program!!!! thank you very much!!!!
Thank you so much . It was so usefull
Super! This just saved me quite a bit of work. Thank you.
excellent work a nice tool
I wonder if there is a way to automatically recognize the waves if the image has a wave of a unique color and if there is a way to do multiple files instead of clicking points one by one. Thanks!
Does make my life easier, thank you
That's great. Thank you very much!
WOW!! Absolutely beautiful, I love it, thanks!!!!
For people asking about logarithmic axis...
You can put the values for calibration of log axis as 1, 2, 3 instead of 10, 100, 1000, and then when you plot the data just take 10^(axisValues).
Best, Thanks
It is working fine. Nice work.
How does it work with log axis ?
Thank you.
Nice work Jiro. Liked it. Very useful for me.
This has been a very useful submission for me. One minor improvement that I could suggest is an option to recalibrate the x-axis and y-axis independently. I think that would be great for plots with multiple y axes.
Won't work in 2013b though
Works so well! Thank you for your contribution Jiro~
Suggestion: automatic recognize curve (if possible)
thanks Jiro, great tool. If you find the time, why don't you go and put in a way to select a continuous color (a line) for instance. This would make clicking along a closed plot unecessary. What do you think ;)
Worked perfectly for me. This is one of the best implementations of a plot digitizer I have ever used. Thanks for sharing your excellent work!
Great tool!
Does exit an updated version to deal with logarithmic axes?
Or maybe some one could give me some clue to implement it in the code... thanks
Many thanks for you, you have solved a very complex problem for me
Thanks for the great tool. I'm currently trying to adapt it a little bit for my use, and bit of help would be appreciated.
I have a bunch of images from which I plan to grab data. However, they only have y axis reference points, so I can't calibrate them properly. The x-axis is on the same scale as the y-axis, so what I want to do is force the origins of both axes to be at the same location. Then I can force the horizontal distance (on screen) between Xo and Xmax to be the same as the vertical distance between Yo and Ymax. However, I don't really understand how the locations of the calibration points are stored and used, so I'm having trouble.
It is very helpful, veru well done
very nice tool!
There are several versions of this type of GUI on the exchange, but this is by far the best one. It incorporates all of the stuff that the other guys are missing, plus the interface is very easy to use. I especially like that it can handle skewed images from really old scanned papers.
Awesome!
Nice Gui, but miss an automatic curve recognition. I'm also using reverseplot
(http://www.mathworks.co.uk/matlabcentral/fileexchange/4316-reverseplot), which has this feature, but a slightly inferior gui.
Hello,
Thanks for this nice tool.
Instead of point, can I get an area by marking a particular region in the bit map.
Regards
Ram
This a great application. I would have one request. Would it be possible to calibrate to the image size, with origin at top left max Y at bottom-left and max X at top-right. It is very basic and not as general as the current calibration procedure using 4points.
I am having issues with zoom and ginput to get the coordinate of a point in an image to change the coordinate system to that point later on in pixel and physical units. Thanks.
A very useful application.
GREAT GREAT GREAT WORK!!!!
Excellent tool - best one of these I've used so far. Log axes? No problem, just type in the exponent as the calibration values.
Suggestions:
* Ask the user if the data should be adjusted if the user recalibrates after grabbing.
* If the scan is not perfectly horizontal it would be nice to have two adjustment points for each xmin, xmax, ymin, and ymax - i.e. support for rotated coordinate transformation.
Super tool!
Need the capability to use log-axes though.
This is one of the best and most useful tool I found here: really compliments!
GREEEEAT,
Is it possible that in the preview box shows the position calibrated and the corresponding pixel?
I plan to use it to calibrate a video to follow a laser spot
This program is ingenious. It is extremely small, easy to use and yet so useful that it makes it the ultimate grab tool.
This script is a lot better than Datathief which I formerly used. It makes extracting data from figures easier and faster!
Does not work. from the first line itself it says unexpected matlab operator..
please help. i think its not identifying 3d
i am using matlab 7.1.0.246 (R14)
Does not work. from the first line itself it says unexpected matlab operator..
please help.
i am using matlab 7.1.0.246 (R14)
for the last six month i am trying to extract the data from the image file. Now i got it. this is very well work for me and all (those who are working Scientific data processing).
Thanks a lot. Good Job.
This is something I was looking for. Thank You. Tip: wouldn't it be nice to extract data point form graphs with logaritmic axes?
Just loved it. Very good interface also.
Very usefull,
Extremely useful. Thank you very much for sharing.
Excellent tool. Thanks for posting.
very useful tool. Thanks a lot.
excellence! I am waiting for the next version which can deal with logarithmic axis. Good luck!
I have uploaded an improved version. It has a better zooming feature (also zoomable during calibration) and a click-n-drag panning feature. I have not yet implemented capability to deal with LOGARITHMIC axes, but that's on my to-do list.
A very useful utility. Suggested additions and improvements are:
1) facility to deal with logarithmic as well as linear axes.
2) allow zoom function to work in calibration mode as well as in data grabbing mode so that axis limits can be defined more accurately.
Sorry, but wenn I start your code, I can see only GUI. If I browse a filename (Load Image) - only a path and image name will be shown, but I can´t see anything... Please inform me what to do, thanks
The imshow command used at line 382 ('iH = imshow(A, map)') does not work in MATLAB R14 SP2. Replacing it with 'iH = image(A);
colormap(map);' solves the problem. Other than that a very useful but of code!
A very good code. I have tried it, it works well.
good piece of code. useful for retrieving data points from images.
perfect... would suggest to improve on finding data automatically when clicked on any particular line on the image