This image was improved or created by the Wikigraphists of the Graphic Lab (Commons). You can propose images to clean up, improve, create or translate as well.
This is a retouched picture, which means that it has been digitally altered from its original version. Modifications: Replace the tinted background with a transparent one, thicken the concentric circles and decrease their number, change the line marking for the interval from 1 to 2 from red and black to just black, remove all text from the image, crop the image to fit the line, numbers, and circles with no border.. The original can be viewed here: Điểm cô lập-Isolated point.jpg: . Modifications made by Begoon.
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