Students, are you still worried about the reference data of the paper? When you find references, you can only find data maps, but the screenshots are not clear enough, and there is no original data drawn by yourself. There is an artifact that can help us solve this problem, that is, a graphic data acquisition tool called Web Plot digitizer.

This tool was developed by Ankit Rohatgi, a doctoral student majoring in chemistry and biomolecular at the University of Notre Dame. The plug-in can extract data from other people's pictures, that is, reverse engineering through data visualization images to extract basic numerical data.

WebPlotDigitizer is a semi-automatic tool, which makes this process very simple: it is suitable for all kinds of charts, including 2D XY charts, bar charts, polar charts, ternary charts, maps and other graphics, and the automatic extraction algorithm can easily extract a large number of data points. The tool is open source and can be used for free.

Tool URL:

https://apps.automeris.io/wpd/index.zh_CN.html

Open it and you can use it directly.

Interface of network drawing digitizer

Let's take histogram and scatter chart as examples to illustrate:

1, histogram

First, click File to import pictures.

Select the 2D bar chart, and then click the alignment axis.

According to the chart, select two points to determine the unit length of the shaft.

According to the picture, we choose two points on the vertical axis.

You can aim at the point with the magnifying glass on the right to reduce the error. Then click Finish.

P 1 is 0 and P2 is 40. Enter it and click OK.

At this time, we can move the cursor to the top of the bar chart for punctuation, with a view to taking the mid-term exam as an example:

We marked the test scores of five students, click on the left to view the data.

Then click Copy to Clipboard and paste into EXCEL.

Select a column with a comma as the separator.

We can separate the two columns of data, and the second column is the test scores of the five students we need.

Do the same thing again and get the final exam results.

Click Clear Data.

Click add point.

Similarly, if the point mark is wrong, you can choose to adjust the point or delete the point, which will not be described here.

After adding points, do the same operation to obtain the following data:

Optimize the data obtained.

Select the histogram to draw in the chart.

Get the graphics we need

2. Scatter chart

We want to get some data. After importing the picture, we choose the two-dimensional X-Y diagram.

Then determine the unit length and punctuate according to the prompt.

Determine the unit length after taking points on the X axis and Y axis respectively.

Mark the red dot to view the data set.

Import data into excel

Adjust the data and draw a scatter plot.

So we got the graphics we needed.

Assuming that the curve is valuable, we can choose the brush in the right area, and according to the color of the curve, choose the foreground color (curve color) as black and the background color as white.

Cover the curve with a brush according to the curve.

Click Run on the right, and you can see that the tool automatically marks data points on the curve.

image data

Copy it to the clipboard, paste it into an excel table, and draw the curve we need.