In general, the problem is that error bars are plotted using different symbolic conventions in different texts, so the automatic extraction would have to be tailored somewhat to each case. An easier approach is to embed the plot into a Graphics frame using Inset, and then use the drawing tools to capture the coordinates you need by hand.
Here is a less automated but more flexible way to get data from a plot:
dataPlot = Import["https://i.sstatic.net/hoeHR.jpg"];
Manipulate[
Graphics[{}, PlotRange -> {{10, 110}, {0, 1}}, Frame -> True,
AspectRatio -> 1/GoldenRatio,
Prolog ->
Inset[Show[dataPlot, AspectRatio -> Full],
p, {Center, Center}, {w, h}]
],
{{p, {Center, Center}}, Locator}, {w, 60, 130}, {h, .5, 2}]
Here, I can now use the Locator
to drag the image around inside the frame of the Graphics
. The sliders let me adjust the width and height of the plot until the frame labels coincide on both axes.
To extract the data from this, click the plus sign at the top right to reveal the menu where you can select Paste Snapshot
. Do this and evaluate the result to get a snapshot of the framed plot.
Now click on the plot to highlight it, followed by .
to see the coordinate tool. Prsse Cmd-c to start copying the coordinates you click. In this way you can assemble the desired data sets.