File Exchange

image thumbnail


version (23.4 KB) by jiro
Extract (pick out) data points off image files.


Updated 01 Sep 2016

View Version History

View License

Editor's Note: Popular File 2018 2019 2020

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 (, MATLAB Central File Exchange. Retrieved .

Comments and Ratings (273)

pc shieh

junhan park

Gwladys Popo

Is there a way to edit the gui to set calibration permanently?

Sankalp Chopkar

Elena Dukhnich

Thank you very much for your work! Very convenient, easy to use and to understand app!


Wenfang Zhang


Thanks! Good job.

Yue Qiu

Thanks very much!
Thanks to your code, I can grab the data I want now.
However, I wonder if it can include more functions such as the implantation of logarithmic coordination.
And also, if the user can be able to grab automatically a data group of one curve.

Jerome Blair

Completely useless in version 2021A. In both 'calibrate' and 'select points' you have to click on a point many times before it registers. I click up to 10 times on a point with a 2 second wait between. The point usually registers after 4-6 tries, but after 10 I give up.

I am using MacOS 10.15.7.

Kylan Tou


excellent tool!
thank you so much! keep it up

dw j

Andrey Er

Really Good.

zhi liu

林桂 辛


Paraskevas Sarantos

this really works, esp. for simple small plots, thanks

Krishnakarthika Gorla

Matthew Loew

Worked great! My only suggestion for improvement would be to retain the calibration points as a data set.

Thomas Hinterbrandner

Eric Delgado

Matin Dehghani

Jamilah Foucher

Nasim Bekka

Guangshuai Zhang

Easy to use, but doesn't work with log scale.

Sergio Yanez-Pagans

Brilliant!. I really hope this can be updated so that it's compatible with the newer versions

Kuzey Isil


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)

Hang Yi

Cansu Yildirim


Michal Bogdanski

Great tool, but does not work with log scales....

Zhangchen HUANG

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

Ibrahim Sanusi

Amin Aba

Joe Bevis

Very good

Alex Blum

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.

Felix Frank


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.

Yuheng Wu

Gerry Zhang

Amir Hassanfiroozi

Love it, thanks

Kuifeng Zhao

Easy to use. Works well.

Travis Petersen

Wonderfully simple and straightforward.

mohan kanth

Joris Meurs

Robert Danforth

Work perfect. Thanks so much!

Amit Singh

Very comfortable in using. Thanks

saeid zendegan

saves a lot of time

Vehzan Rustomji

Basit Abdul

Qihao Yu

Very convenient. Thanks!


Very good! I have tried with different softwares and the results from grabit agree very well, thought more easy.

Chad Greene

Fantastic. Really streamlines the process of digitizing and saving plots from published papers. Thanks Jiro!

Aniket Patil

Very useful


Pranay Jain


Carlos Figueiredo

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.

Michael Himmelhaus

Great, exactly what I needed.

Edward Longman

Jack Bi

Very beautiful.

Kai Mun Chan

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.

David Rivas

Nicely done!

Jose Ortega


Kirk Dolan

Ufuk Tamer




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?

Dick Sterenborg

Great program. Simple and works well. Indeed log scales might come in handy, although not essential.

Maia Szalavitz

Tobias Kistler

Dong Zhang


thong ly

Very very good! Thanks.

Vikas Sharma

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

Govindaraj P

Very useful. Thank you jiro.

Josep Guasch

Very useful, thanks for the work!

Safwana Razak

Umut Pekdüz

Victor Quezada


it's brilliant

Davide Vatteroni

Amazing script!

Jatin Gera

Alexander May

Simply brilliant! Thank you!

Josh Philipson


Thank you so much for that awesome tool. I've used it plenty of times over the years. Keep up the good work!

Tomas Hulan

A perfect tool! Thanks!

Chuchu Xiang

Kay Ackermann

Sameh Khan

Excellent code. FTI for those struggling with Drawmode, Erasemode deprecation.


'drawmode' . , 'fast', ...
'SortMethod' , 'depth', ...

and delete 'Erasemode', 'normal'

Your code should work fine in newer versions of MatLab, if those are the only issues.

Alex Dokoutchaev

Miguel Chavez

Mohammed Alam

Caroline Pavlak

Jinpu Lin

Ricardo Brito

Fernando Zigunov

Ashwin Pathak

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)];

Álvaro Romero Calvo



Not supporte by R2017a :-(

Chuhan Deng

Great Functions!

Naftali Herscovici

Great utility! Thanks!

Federico Danzi

An extremely useful tool! Thanks!

zhumei sun

does it work for double Y axes?

Lucia Mascotelli

Is it possible to use it when one axis is in log scale and not linear?

mod rany

Really great tool. I would suggest to build in an interpolation as a post processing option.

Vikram Babu

Great tool to extrapolate raw data from stress-strain curve images. Thanks for a great macro Jiro!

Wenyin Gong

Harish Sasikumar

kelvin zhang


Dennis Vogt

Slim Shady

How to make this understand that an axis is on log scale


Effective tool. Useful with stress-strain curves


tian chang




Milad Jalali

Rodrigo Botelho

Isaac Gentle


Alessandro Cancelli

William Afonso

Abdulaziz Abutunis

Great tool.. Thank you

Antoine Debugne

Martin Erinin


Abhijeet chausalkar

Kang Gao

Nitisha Ahuja

How can I use it for log log plot?


Very useful function,

Lama Hamadeh

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.

Haibin Pan

It's great.Thanks the author.

Muzaffer Ozsecen

Paolo Di Re

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.

xingya chen


Kurt Duclos

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.

Dale Smith

shiwen wang

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.

Beichuan Hong

Thx for this file!

Caroline Loss

excellent tool!
thank you so much!





Nabin Paudel

Error message, unable to expand "" into downloads. Any solutions for this issue yet ?


Rosemary Le

There is an error message when attempting to unzip the file:

"Unable to expand "" 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.

Prabhat Chandra

Srikanth Divi

rahul verma

How we can save the image, after garbing points.
is there any way to get the selected image.

Chenguang Zhang

great tool!

Yonatan Calahorra

Thank you for this!


Shabareesh Kumar

this is a very use full application,
Thank you

Tai Yunxin

Qiyan Lian

It is really a amazing GUI,but there is a warning, EraserMode will not be it should be updated.

Qiyan Lian


Really easy and straightforward to use. No unnecessary complications or extra features. Works great!


Benjamin Cheong

Mohammad Mohammadi

Zac Milne

I use this all of the time for analyzing data from others' work. I wish there was a function to deal with log axes.

Paul Martin

Just what the doctor ordered, worked well first time. Thank you Jiro!


Deepan J

Euler Oliveira

It worked well and helped me a lot. Thanks!

Jake G

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.


Hoang Anh Nguyen


Robert Richardson

Very useful software! Very intuitive and easy to use. Exactly what I needed.

Zhang Wenqiang

very good software, so much thanks!


Excellent. Thanks a lot.

Joris Meurs

Great work! Very useful


Very useful code. This is what I was looking for. Thanks


Andrew Stamps

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.

mohit raghuwanshi



aaron pung

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!

Erik Reinertsen

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

Alejandra Matamoros


Super! This just saved me quite a bit of work. Thank you.


Yuan Feng

Gabriel Chatterjee

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!

Matthias Eberlein

Does make my life easier, thank you

Faezeh F

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.



Abhishek Anchal

Nice work Jiro. Liked it. Very useful for me.


Keith Lindsay

Andrew Stamps

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

Roberto Herrera

Yuji Zhang

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 ;)

Danny Sale

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

Zhen Chen


Ahmed Ali

Many thanks for you, you have solved a very complex problem for me

James Herman


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!


Nassim Khaled


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.



Enrico Segre

Nice Gui, but miss an automatic curve recognition. I'm also using reverseplot
(, which has this feature, but a slightly inferior gui.

Ram Lakshmi


Thanks for this nice tool.
Instead of point, can I get an area by marking a particular region in the bit map.

Torsten Vogel

Donat-Pierre Luigi

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.

a c


ghgf ghf

Sigmund As

Excellent tool - best one of these I've used so far. Log axes? No problem, just type in the exponent as the calibration values.

* 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.

Mikkel Pedersen

Super tool!

Need the capability to use log-axes though.

Lorenzo Luini

This is one of the best and most useful tool I found here: really compliments!

Jhon Gonzalez


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

Iomsn Egenson

This program is ingenious. It is extremely small, easy to use and yet so useful that it makes it the ultimate grab tool.

Amandine Cagnioncle

This script is a lot better than Datathief which I formerly used. It makes extracting data from figures easier and faster!

Avi Pal

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 (R14)

Avi Pal

Does not work. from the first line itself it says unexpected matlab operator..
please help.
i am using matlab (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).

Jean-Luc Dellis

Thanks a lot. Good Job.

Eduard van der Zwan

This is something I was looking for. Thank You. Tip: wouldn't it be nice to extract data point form graphs with logaritmic axes?

Pankaj Porwal

Just loved it. Very good interface also.

Hector Mancha

Very usefull,

Cong Le

Lars Sundstrom

Extremely useful. Thank you very much for sharing.

Nick Peters

Excellent tool. Thanks for posting.

Seis Errs

very useful tool. Thanks a lot.

John Terry

excellence! I am waiting for the next version which can deal with logarithmic axis. Good luck!

iman satria

Jiro Doke

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.

Dick Beresford

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.

Leo Medo

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

Tony Jones

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!

Dewa Arsa

A very good code. I have tried it, it works well.

Siva Venkat

good piece of code. useful for retrieving data points from images.

radha proddaturi

perfect... would suggest to improve on finding data automatically when clicked on any particular line on the image

Chen-Fen Huang

MATLAB Release Compatibility
Created with R13
Compatible with any release
Platform Compatibility
Windows macOS Linux


Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!