| Re: Recovery from PostScript file [message #18427] |
Wed, 12 January 2000 00:00 |
Liam E. Gumley
Messages: 378
Registered: January 2000
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Senior Member |
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Chris Roberts wrote:
> I have a user who generated a PostScript file of his IDL data as a graph,
> and has now lost his data file. Is there anything sensible I can do to help
> him recover some of the data from the PostScript file?
An indirect method is to scan the printed graph into a high resolution bitmap,
and then use a program like QuickTrace to digitize the data points:
http://servermac.geologie.uni-frankfurt.de/QuickTrace.html
I can also imagine converting the Postscript file to a bitmap graphics file
using ImageMagick, and then using some clever IDL code to extract the outlines
of the plotted points:
http://www.wizards.dupont.com/cristy/ImageMagick.html
However I think it would be best if you just tell your user that he blew it, and
that he should learn to make backups. This will serve him better in the long run
than trying to extract data points from plots.
Cheers,
Liam.
http://cimss.ssec.wisc.edu/~gumley
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| Re: Recovery from PostScript file [message #18428 is a reply to message #18427] |
Wed, 12 January 2000 00:00  |
cjengo
Messages: 28
Registered: June 1999
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Junior Member |
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In article <85ib48$h5n$1@jura.cc.ic.ac.uk>,
"Chris Roberts" <c.roberts1@ic.ac.uk> wrote:
> I have a user who generated a PostScript file of his IDL data as a
graph,
> and has now lost his data file. Is there anything sensible I can do
to help
> him recover some of the data from the PostScript file?
>
> Thanks.
>
>
First thing that comes to my mind is to convert the postscript file to
a tiff, read it into an array, then scan each column from the bottom
until the x-axis is reached, then count pixels until the data plot is
reached. Of course you'd have to account for axis labels and so forth,
but you could mask those out in an IP program before rasterizing it.
That also wouldn't get the actual data values back, but at least the
shape of the curve is better than nothing.
Chris
--
_______________________________________
Chris Jengo - Senior Imaging Scientist
Earth Satellite Corp. - Rockville, MD
cjengo@earthsat.com
Sent via Deja.com http://www.deja.com/
Before you buy.
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| Re: Recovery from PostScript file [message #18430 is a reply to message #18427] |
Wed, 12 January 2000 00:00 |
davidf
Messages: 2866
Registered: September 1996
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Senior Member |
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Chris Roberts (c.roberts1@ic.ac.uk) writes:
> I have a user who generated a PostScript file of his IDL data as a graph,
> and has now lost his data file. Is there anything sensible I can do to help
> him recover some of the data from the PostScript file?
With the exception of providing him with a good ruler with lots of
gradations, no. :-(
The PostScript file has as much relationship to the data as a
picture of your user has with your user.
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting
Phone: 970-221-0438 E-Mail: davidf@dfanning.com
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Toll-Free IDL Book Orders: 1-888-461-0155
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