WebPlotDigitizer
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automeris-io
Feature request: set origin to zero
When reading a curve and later calculate with this curve, it is necessary to work with a (0,0) origin. Otherwise some other programs will calculate some garbage. Usually a user can not pick the point exactly to 0,0. So there might be an option "set origin to zero", which searches for the value close to 0,0 and sets it to 0,0.
In the past, I used the digitizer on multiple 2D x-y charts with two of the four reference points not at (0,0) as symbolized by the picture below:
The need not to be on either abscissa and ordinate, either; an intersection of the inner grid often equally works good enough for me. On a second point, you may move the reverence points (when still active / selected and highlighted green) with the arrow keys of the computer keyboard, too. The little window in the top right corner may serve as zoom locally around this point (instead of magnifying all of the picture):
If the 5fold magnification does not offer enough resolution, you may alter this, e.g., to 20x. Below (20x magnification of the cross-hairs window), still at the point for x = 0, y = 1.5.
These steps may contribute to lower the vertical / horizontal offset. May you quantify an offset along current and potential which is good enough for you? Maybe it is possible to scan the picture a twice, e.g. at 300 dpi, or 600 dpi optical resolution?
The resolution is not the problem, standard resolution without zoom is okay. When reading a lot of curves, doing zooming for all is not practical. Usually users of this tool use the data to do some calculation with it. In some cases, you can have only positive data (and the graph is only providing positive data). Due to working with the tool, the origin is sometimes a bit negative, or not exactly zero (what is a problem for further calculating programs. lower offset does not help here). For all other points, the offset does not matter. So this is a request to provide an option to set the point next to the origin to 0,0.
With references about x (they don't need to be defined accurately about y), and y (which don't need to be fancy about x)
I was able to pic some points of an other graph (points in blue). Lacking the original I/V-plot without the red dots by you, the digitization obviously skips most of the diagram already with some lesser offset:
The picture used as well as the project as-such are enclosed in the .zip archive attached below.
I object the statement «For all other points, the offset does not matter.». If the offset is corrected for the one supposed to be at (0,0), e.g., by moving this very point a bit to the left and a bit upward, the whole trace should be affected. Why not enclosing the complete project (incl. the picture) into a .zip to serve as a reference data set for further improvement of the digitizer?
For the other perspective, there was a thread pointing to batch-like processing of illustrations of same dimensions here. I can't share experience with this one, though.