g3data [ -max x y ] [ -scale factor ] [ -scroll ] file
DESCRIPTION
This manual page documents briefly the
g3data command.
g3data is a program that extracts data
from scanned graphs. For example, graphs are typically published in
scientific journals without tables of the actual data; g3data makes the
process of extracting these data easy.
OPTIONS
-max x y
If picture is larger x-wise than x or y-wise than y,
the picture is scaled down accordingly otherwise this
parameter has no effect.
-scale factor
Scales the picture size by factor. This parameter nullifies
effect of the -max parameter.
-scroll
Picture is viewed through a viewport with scrollbars,
use this for very large pictures if you need accuracy.
-coords llx lly rux ruy
Preset the coordinates of the left lower (ll) corner
and the right upper (ru) corner.
-errors
Print out the error of the x value in column 3 and the
error of y value in column 4 of the output.
-lnx
Use logarithmic scale for x coordinates.
-lny
Use logarithmic scale for y coordinates.
file
The filename of the graph. This parameter is required.
Supported image formats: JPEG, GIF, PPM, PGM, XPM, PNG, TIFF,
EIM.
HINTS
To access fullscreen mode use the F10 key.
Hint for increased accuracy : Use -scale with a large parameter
to achieve finer granularity and thus smaller errors.
TESTING AND USAGE
There are two testdata files included with the program: test1.gif
and test2.gif. Their corresponding data can be found in test1.values
and test2.values.
To test the program, start it with the command g3data
test1.gif or with g3data test2.gif. When
the program has started, click on the button labelled Set
point 1 on X axis and lay out the corresponding point on
the image by pressing on it. Do the same for point 2 on the X axis and
points 1 and 2 on the Y axis. The axis points can also be layed out by
pressing the middle mouse button for the x axis and the right button
for the y axis. Fill out the entry boxes for the values of the axis
points. Then continue to lay out the desired data points on the graph
itself.
If by accident you lay out a data point where it doesn't belong,
you can remove it by pressing the Remove last
point button. To remove all layed out data points, press the
Remove all points button. The axis points can be
reset by pressing the corresponding button.
After all the points been layed out, press the Print
data button and the coordinates of the data will be printed
out through stdout. If you'd like to write the data to a file, fill
out the filename entry box and press the Print to
file button.
Remember to apply the logarithmic scale on x axis for
test2.gif.
AUTHOR
g3data is written and maintained by Jonas
Frantz jonas.frantz@helsinki.fi. The g3data
home page is
This manual page was created by Peter S Galbraith <psg@debian.org> for the
Debian GNU/Linux system (but may be used by others) using the command's help
files. Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU GPL Version 2
or any later version published by the Free Software
Foundation.
