Hi Folks, This is off-topic R-wise, but it may be close to the heart of many R-users, so I think it may be the best place to ask! Users of 'gv' (the "front end" to ghostscript) will be aware of the little window which gives you the x-y coordinates (in points = 1/72 inch) of the position of the "cross-hair" mouse cursor. These coordinates are those of the corresponding position on the printed page, relative to some origin. I have often used this to extract numerical values for data from graphs in Postscript files (also PDF files, after you have converted them to PS). Then (veering back on topic ... ) you can submit the numerical data to R and try your own analyses on these data, and compare with what the article does. However, this little window only gives the numbers in whole points. Say a smallish graphic may print out 3 inches wide or high. Then you get precision of 1/216 per 3 inches or 0.4% of full scale. This can be adequate on many occasions, but can be on the coarse side on other occasions. Even for a 6-inch-wide/high graph, you only get down to 0.2% of full scale. If it were possible to induce 'gv' to display these coordinates in tenths of a point, then much greater precision (as adequate as one can expect to hope for when, in effect, "measuring off the graph") could be obtained. Does anyone know: a) Whether it is possible to persuade 'gv' to give this display in fractional points (my own search of the documentation has not revealed anything); b) Of any alternative to 'gv' as PS viewer which would provide this capability? With thanks, and best wishes to all, Ted. -------------------------------------------------------------------- E-Mail: (Ted Harding) <ted.harding at nessie.mcc.ac.uk> Fax-to-email: +44 (0)870 094 0861 Date: 15-Jun-07 Time: 16:13:21 ------------------------------ XFMail ------------------------------
This doesn't answer your original question, and isn't much help unless you're on a mac, but there's a nice looking program that makes this kind of graph scraping really easy: http://www.arizona-software.ch/applications/graphclick/en/ Hadley On 6/15/07, Ted Harding <ted.harding at nessie.mcc.ac.uk> wrote:> Hi Folks, > > This is off-topic R-wise, but it may be close to > the heart of many R-users, so I think it may be > the best place to ask! > > Users of 'gv' (the "front end" to ghostscript) will > be aware of the little window which gives you the > x-y coordinates (in points = 1/72 inch) of the position > of the "cross-hair" mouse cursor. These coordinates > are those of the corresponding position on the printed > page, relative to some origin. > > I have often used this to extract numerical values > for data from graphs in Postscript files (also PDF > files, after you have converted them to PS). Then > (veering back on topic ... ) you can submit the > numerical data to R and try your own analyses on > these data, and compare with what the article does. > > However, this little window only gives the numbers > in whole points. Say a smallish graphic may print > out 3 inches wide or high. Then you get precision > of 1/216 per 3 inches or 0.4% of full scale. This > can be adequate on many occasions, but can be on > the coarse side on other occasions. > > Even for a 6-inch-wide/high graph, you only get down > to 0.2% of full scale. > > If it were possible to induce 'gv' to display these > coordinates in tenths of a point, then much greater > precision (as adequate as one can expect to hope for > when, in effect, "measuring off the graph") could be > obtained. > > Does anyone know: > a) Whether it is possible to persuade 'gv' to give > this display in fractional points (my own search > of the documentation has not revealed anything); > b) Of any alternative to 'gv' as PS viewer which would > provide this capability? > > With thanks, and best wishes to all, > Ted. > > -------------------------------------------------------------------- > E-Mail: (Ted Harding) <ted.harding at nessie.mcc.ac.uk> > Fax-to-email: +44 (0)870 094 0861 > Date: 15-Jun-07 Time: 16:13:21 > ------------------------------ XFMail ------------------------------ > > ______________________________________________ > R-help at stat.math.ethz.ch 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. >
On 6/15/07, Ted Harding <ted.harding at nessie.mcc.ac.uk> wrote:> Hi Folks, > > This is off-topic R-wise, but it may be close to > the heart of many R-users, so I think it may be > the best place to ask! > > Users of 'gv' (the "front end" to ghostscript) will > be aware of the little window which gives you the > x-y coordinates (in points = 1/72 inch) of the position > of the "cross-hair" mouse cursor. These coordinates > are those of the corresponding position on the printed > page, relative to some origin. > > I have often used this to extract numerical values > for data from graphs in Postscript files (also PDF > files, after you have converted them to PS). Then > (veering back on topic ... ) you can submit the > numerical data to R and try your own analyses on > these data, and compare with what the article does. > > However, this little window only gives the numbers > in whole points. Say a smallish graphic may print > out 3 inches wide or high. Then you get precision > of 1/216 per 3 inches or 0.4% of full scale. This > can be adequate on many occasions, but can be on > the coarse side on other occasions.If you are mostly concerned about small figures, one possibility is 1. zoom out to a level where you're happy with the pixel resolution 2. do a screen capture using 'import' 3. use gimp (which has the same feature, with more units) gimp can also load PS files directly, with a user supplied zoom factor at load time, but only one page at a time, AFAICT. -Deepayan
Check out the engauge digitizer: http://digitizer.sourceforge.net/ On 6/15/07, Ted Harding <ted.harding at nessie.mcc.ac.uk> wrote:> Hi Folks, > > This is off-topic R-wise, but it may be close to > the heart of many R-users, so I think it may be > the best place to ask! > > Users of 'gv' (the "front end" to ghostscript) will > be aware of the little window which gives you the > x-y coordinates (in points = 1/72 inch) of the position > of the "cross-hair" mouse cursor. These coordinates > are those of the corresponding position on the printed > page, relative to some origin. > > I have often used this to extract numerical values > for data from graphs in Postscript files (also PDF > files, after you have converted them to PS). Then > (veering back on topic ... ) you can submit the > numerical data to R and try your own analyses on > these data, and compare with what the article does. > > However, this little window only gives the numbers > in whole points. Say a smallish graphic may print > out 3 inches wide or high. Then you get precision > of 1/216 per 3 inches or 0.4% of full scale. This > can be adequate on many occasions, but can be on > the coarse side on other occasions. > > Even for a 6-inch-wide/high graph, you only get down > to 0.2% of full scale. > > If it were possible to induce 'gv' to display these > coordinates in tenths of a point, then much greater > precision (as adequate as one can expect to hope for > when, in effect, "measuring off the graph") could be > obtained. > > Does anyone know: > a) Whether it is possible to persuade 'gv' to give > this display in fractional points (my own search > of the documentation has not revealed anything); > b) Of any alternative to 'gv' as PS viewer which would > provide this capability? > > With thanks, and best wishes to all, > Ted. > > -------------------------------------------------------------------- > E-Mail: (Ted Harding) <ted.harding at nessie.mcc.ac.uk> > Fax-to-email: +44 (0)870 094 0861 > Date: 15-Jun-07 Time: 16:13:21 > ------------------------------ XFMail ------------------------------ > > ______________________________________________ > R-help at stat.math.ethz.ch 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. >