when i'm trying to plot in my code, results seems to be flipped upside down…how can i correct it, and why it i that way? thank you in advance
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When you use image() or imagesc() or imshow(), MATLAB assumes you want "axis image", one side effect of which is to set the axis YDir to 'reverse'. It does this so that the "top" (lower row numbers) of the image show up at the top of the screen, because that is how people typically construct image arrays. Normally MATLAB follows Cartesian plotting conventions, where the low values are at the bottom of the screen with Y increasing upwards.
If you want your Y to increase from the bottom then you need to
set(gca, 'YDir', 'normal')
after you display your image. If this plots your image upside down from what you want, then you will need to ask to display flipud() of the image matrix,
imshow() by default sets YDir reverse so that the "top" of the array (lowest row number) appears at the top of the screen (which would otherwise correspond to highest row number).
When you then plot the points without YDir reverse then they appear upside down.
Best Answer