Turning y axis upside down in MATLAB
Is there a way to turn the y axis upside down in matlab plots, so that the positive direction of the y axis, instead of up, points down ?
(I beg of you; please do not say, print it out, then turn the pap开发者_如何学Goer around ;-)
The 'YDir'
axes property can be either 'normal'
or 'reverse'
. By default it is 'normal'
for most plots, but some plots will automatically change it to 'reverse'
, such as the image
or imagesc
functions.
You can set the y-axis direction of an axes with either the set
function or dot indexing (in newer MATLAB versions):
h = gca; % Handle to currently active axes
set(h, 'YDir', 'reverse');
% or...
h.YDir = 'reverse';
I'm baffled by some of the other answers saying that the 'YDir'
property has somehow disappeared or is giving an error. I haven't seen any such behavior in versions of MATLAB from 2013, 2014, or 2016. There are only two potential pitfalls I came across:
The property can't be set with a cell array, only a character string:
>> set(gca, 'YDir', {'reverse'}); Error using matlab.graphics.axis.Axes/set While setting property 'YDir' of class 'Axes': Invalid enum value. Use one of these values: 'normal' | 'reverse'.
although this works:
set(gca, {'YDir'}, {'reverse'}); % Property name is also a cell array
The
gca
function can't be used interchangeably as a handle when performing dot indexing (which is why I first saved it to a variableh
in the above example):>> gca.YDir Undefined variable "gca" or class "gca.YDir". >> gca.YDir = 'reverse' % Creates a variable that shadows the gca function gca = struct with fields: YDir: 'reverse'
Finally, if you want some code that will toggle the 'YDir'
property no matter what its current state is, you can do this:
set(gca, 'YDir', char(setdiff({'normal', 'reverse'}, get(gca, 'YDir'))));
% or...
h = gca;
h.YDir = char(setdiff({'normal', 'reverse'}, h.YDir));
The command
axis ij
Will also reverse the Y-axis (negative above x-axis; positive below).
The solutions on the top of the stack did not work for me,
imagesc(x,y,data) % results in a flipped plot, the y axis is upside down
set(gca,'YDir','reverse'); % gives an error
axis ij; % still gives the flipped plot
what did work was the following:
imagesc(x,y,data); axis xy; % results in the correct plot
The YDir
property has vanished in the matlab version (2013 and up) that I'm using.
To update this answer, since it is still a popular Google result: As of R2014a, the correct way to flip the Y axis is the following:
>> axis ij
This change can be reversed through the following command
>> axis ji
To flip the X or Z axes, do the following
set(gca,'XDir','reverse');
set(gca,'ZDir','reverse');
Personally, I think it would have been easier to keep the YDir option, but what do I know.
As an alternative to YDir
(for some reason I cannot currently see) you can rotate the axes with view
. To turn the y-axis upside down, use
view(0,-90);
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