Digitizing the Plot

Hi!

Wanted to check if there are any packages available for getting the
(x,y) data points of a graph or a plot, which is in the image format.
Say, the plot could be a published report, and I want to get the points
of the curve plotted. (I am speaking something related the subject
discussed in http://www.uniphiz.com/digitizing.htm)

I am not aware of an R-package but there are several applications that
produce tables from graphs which you can import into R afterwards. A
few examples:

  g3data (LINUX, opensource)
  engauge (LINUX/Windows, opensource)
  Grab it! (Windows, commercial)
  Datathief (LINUX/Windows/Mac, shareware)
  UN-SCAN-IT (Windows/Mac, commercial)

Google digs up quite a few additional hits with "digitizing graph
data".

cu
	Philipp

Dr. Philipp Pagel
Lehrstuhl f?r Genomorientierte Bioinformatik
Technische Universit?t M?nchen
Wissenschaftszentrum Weihenstephan
85350 Freising, Germany
http://mips.gsf.de/staff/pagel

The grImport package seems to provide such possibility for vector  
graphics,

http://www.stat.auckland.ac.nz/~paul/Talks/gddg.pdf

imageJ is another open-source option.

baptiste

Hi R,



Wanted to check if there are any packages available for getting the
(x,y) data points of a graph or a plot, which is in the image format.
Say, the plot could be a published report, and I want to get the  
points
of the curve plotted. (I am speaking something related the subject
discussed in http://www.uniphiz.com/digitizing.htm)





Thanks,

Shubha





This e-mail may contain confidential and/or privileged i...{{dropped: 
13}}

______________________________________________
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

_____________________________

Baptiste Augui?

School of Physics
University of Exeter
Stocker Road,
Exeter, Devon,
EX4 4QL, UK

Phone: +44 1392 264187

http://newton.ex.ac.uk/research/emag

I don't know of anything that does the automated process like the example software you link to, but here is one procedure that you can use to "do it by hand".

1. Brind the graph into R and plot it (as an image) using rimage or EBImage (or other) packages.

2. use the locator function to find the coordinates (under the current user coord system) of 2 points that you know the coordinates of (in the scale of the graph, desired coord system).

3. Use the updateusr function from the TeachingDemos package to convert the coordinates to match the axes (using the points from the previous step).

4. Use the locator function and click on the points/curve in the graph.  The result will be an approximation to the data of interest (you may want to round or do other clean-up, or just use as is).

Hope this helps,

Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Shubha Vishwanath Karanth
> Sent: Thursday, April 16, 2009 9:44 AM
> To: r-help at stat.math.ethz.ch
> Subject: [R] Digitizing the Plot
> 
> Hi R,
> 
> 
> 
> Wanted to check if there are any packages available for getting the
> (x,y) data points of a graph or a plot, which is in the image format.
> Say, the plot could be a published report, and I want to get the points
> of the curve plotted. (I am speaking something related the subject
> discussed in http://www.uniphiz.com/digitizing.htm)
> 
> 
> 
> 
> 
> Thanks,
> 
> Shubha
> 
> 
> 
> 
> 
> This e-mail may contain confidential and/or privileged
> i...{{dropped:13}}
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-
> guide.html
> and provide commented, minimal, self-contained, reproducible code.