Could you tell me how can I change an axis "multiplier"? I mean a value I circled in the picture, let's say I would like to have x10^3 instead of x10^4.
As of R2015b it is part of the Numeric Ruler Properties:
ax = get(gca);
ax.YAxis.Exponent = -3;
I have little bit tricky solution:
Set YTickMode to manual.
Set your own YTickLabel.
Place the text on top with your desired multiplier.
here is:
set(gca, 'YTickMode', 'manual');
set(gca, 'YTickLabel', get(gca,'YTick') / 1000);
text(0, 1.02 * get(gca,'YLim')(2), 'x 10^3');
Play with the multiplier 1.02 in the third line to place your text to the good place.
You can use the following Matlab Central tick2text: create easy-to-customize tick labels
http://www.mathworks.com/matlabcentral/fileexchange/16003-tick2text-create-easy-to-customize-tick-labels
along with the sprintf formatting.
Scale your data by 0.1, which gives you the multiplier you want.
Then override the tick labels so that tick 1.0 is labelled 10, etc.
Related
I'm representing a surface using "surf" function, with a colorbar. I would like to keep the default ticks of the colorbar, but add a custom tick on this colorbar, at a specific value (that I could make red to distinguish it from other ticks for example). Any idea on how to add a custom tick like that with keeping existing ticks on the colorbar ?
Thanks
As Luis mentioned in the comments, you can add an additional tick mark like so
h = colorbar;
newTick = 0.75;
h.Ticks = sort([h.Ticks newTick]);
If you want to add a line to the bar, the easiest thing (I think) is to use an annotation which is positioned relative to the figure (the same as the colorbar), so we can overlay it
pos = h.Position;
r = (newTick - min(h.Ticks))/(max(h.Ticks)-min(h.Ticks));
annotation( 'line', pos(1)+[0, pos(3)], [1, 1]*(pos(2)+pos(4)*r), ...
'color', [1,0,0], 'linewidth', 2 );
I'm setting the x position of the annotation to match the left and right sides of the colorbar, and the y position to match the bottom plus the relative % of the height according to the tick value.
Result:
Similarly, you could use annotatation exclusively to just get a red label, it's a little more convoluted to get everything lined up correctly, you have to make sure the text box is wide enough to be on a single line and vertically aligned to the middle to get the position right:
h = colorbar;
newTick = 0.75;
pos = h.Position;
r = (newTick - min(h.Ticks))/(max(h.Ticks)-min(h.Ticks));
h = 0.2;
annotation( 'textbox', [pos(1)+pos(3)/2, (pos(2)+pos(4)*r)-(h/2), pos(3)*2, h], ...
'color', [1,0,0], 'string', ['- ' num2str(newTick)], 'linestyle', 'none', ...
'VerticalAlignment', 'middle' );
I would like to add labels to some points plotted using the command scatter. For the sake of simplicity, let's say I have only one point:
x = 10;
pointSize = 100;
fontSize = 20;
P = scatter(x, 0, pointSize, [0,0,0], 'filled');
text(x, 0, 'pointLabel',...
'HorizontalAlignment', 'center',...
'VerticalAlignment', 'bottom',...
'FontSize', fontSize);
The problem with the previous commands is that the text pointLabel overlaps with the point P depending on the values assigned to the properties pointsize and fontSize.
I have read the documentation of the text command, but the examples only show how to put a label horizontally aligned with a specific point in the diagram. If the alignment needs to be horizontal it is easy, but I could not find a general way to compute the y coordinate of the label pointLabel from the values of the other dimensions.
Clearly I can reach a good alignment by testing various combinations of values, but I am looking for a general solution.
Is there anyone who can help me?
This assumes you are using >=R2014b, though it can also be accomplished in older versions using set and get commands.
When a text object is created, its default units are data coordinates, but those can be changed. In your case, I'd go with points.
x = 10;
pointSize = 100;
fontSize = 20;
P = scatter(x, 0, pointSize, [0,0,0], 'filled');
t = text(x, 0, 'pointLabel',...
'HorizontalAlignment', 'center',...
'VerticalAlignment', 'bottom',...
'FontSize', fontSize);
% It's always a good idea to switch back to the default units, so remember them.
originalUnits = t.Units;
t.Units = 'points';
% Shift the text up by the sqrt(pi)/2 times the radius of the point
t.Position(2) = t.Position(2) + sqrt(pointSize)/2;
t.Units = originalUnits;
Check out Text Properties for more info. If you want to get really sophisticated, you can use the read-only property Extent and your known marker size and position to calculate when a label is overlapping one of your points. Since the default unit is in data space, no conversions are necessary.
If you're working with an older version of MATLAB, all of these options and properties are still available, you just have to work a little harder to use them. For instance, you can't direction set the position as above, but you would instead use get to assign it to a temporary variable, change it, and then use set to update. More lines of code, but ultimately the same effect.
I'd like to relabel the radial tick markers in the following polar log plot:
f = figure ;
t = 0:0.01: pi/2 ;
polar(t, 10 * log10(cos(t))/(50) + 1)
from 1, 0.8, 0.6, 0.4, 0.2 to 0, -10, -20, -30, -40 (i.e. radial dB ticks).
Trying some of the methods from Fixing the Radial Axis on MATLAB Polar Plots, I was able to relabel the markers provided my tick markers were positive and increasing.
I tried the following based on How to remove Rho labels from Matlab polar plot?
rho_labels = {'1' '0.8' '0.6' '0.4' '0.2'};
rho_labels2 = {'0' '-10' '-20' '-30' '-40'};
for r=1:length(rho_labels)
ff = findall(f, 'string', rho_labels{r}) ;
ff = rho_labels2{r} ;
end
but it also didn't work (seems to do nothing, so I suspect I'm operating on a copy of the find results not handled).
How can these tick markers be adjusted? Also, if I wanted a different number of concentric circles than 5, how can that be done (for example, 4 subdivisions with -40 dB at the "origin".)
Here is a way to rename the radial tick labels. Be warned that if there is a match between any radial and angular tick mark labels, both will be replaced and the angular labels will be wrong. But the angular tick labels are fixed as 0, 30, 60, ..., 330, so as long as the radial tick labels don't include these values, you should be fine.
What the code does is find all the text in the plot using findall, trim the blank spaces at the front of each string, then, for each entry in rho_labels, set the string entry corresponding to the tick label with that identifier to the corresponding entry in rho_labels2.
f = figure ;
t = 0:0.01: pi/2 ;
polar(t, 10 * log10(cos(t))/(50) + 1)
rho_labels = {'1' '0.8' '0.6' '0.4' '0.2'};
rho_labels2 = {'0' '-10' '-20' '-30' '-40'};
ff = findall(f,'type','text');
t=strtrim(get(ff,'String'));
for r=1:length(rho_labels)
set(ff(strcmp(t,rho_labels{r})),'String',rho_labels2{r})
end
To modify the number of rings, I think think of anything better than modifying polar.m and creating your own custom polarMOD.m function. If you do this you can also do the radial labels as well. In fact, there might be such a function on the MathWorks File Exchange.
I have a function say Echo of size 100*100. I use:
x=linspace(-5000, 5000, 100); y=linspace(-200, 200, 100);imagesc(x, y, Echo);
I see the image is not properly oriented, so if I use:
Echo=rot90(Echo); imagesc(x, y, Echo);
I get the desired image but the yscale is starting from 200 (lower right) to -200 (upper right). I want -200 (lower right) and 200 (upper right). How do I do that?
You can try:
flipud on the matrix
or modify the figure/axes properties: axis ij (compare with axis xy)
In general if you want to reverse the direction of one of the axes relative to the normal orientation used in figures (example here: Y axis), use
set(gca,'YDir','reverse')
Edit
Since imagesc shows y axis in reverse orientation by default, try the following:
set(gca,'YDir','normal')
Note that in fact this is equivalent to #Bonlenfum's alternative suggestion of axis xy
I am currently working on adding annotations to satellite images in MATLAB. Since the color underneath each text field can vary quite a lot, I want to use a background color under the text to make it easier to see and read.
However, when I do this, a lot of the terrain gets obscured. I though of trying to make the background color for each text box semi transparent, but hit a dead end trying to come up with a solution.
Any ideas? I was hoping for some UI-element where I could just set the 'facealpha' to maybe 0.5. I also need the text to support being rotated (as can be seen in the examples below).
Below is some example code and the resulting image. The workspace with the satellite data can also be found in the link:
Example workspace
figure(1);clf
imagesc(xx,yy,Map);
hold on
plot(xInspection,yInspection,'g.-')
% # Two ways of making a rotated text annotation.
% # Cant make background semi-transparent
testAnno= annotation('textarrow',[0.5 0.5],[0.5 0.5], ...
'string','textarrow annotation', ...
'HeadStyle','none','LineStyle', 'none',...
'TextRotation',asin(directionVec(1))*180/pi,...
'TextBackgroundColor',[0.7 0.7 0.7]);
testText = text(mean(xInspection),mean(yInspection),'text annotation', ...
'rotation',asin(directionVec(1))*180/pi, ...
'HorizontalAlignment','right', ...
'color',[0 0 0], ...
'backgroundcolor',[0.7 0.7 0.7], ...
'fontsize',8);
It doesn't look like either annotation or text return HgObjects that have BackgroundAlpha properties (they might exist but I wasn't able to find them using getundoc or by trying various different hacks).
I was able to get something working by drawing the background myself. Here is a simple proof of concept:
f = figure;
tObj = text(.5, .5, 'text object', 'FontSize', 20);
set(gca,'XLimMode', 'manual', 'YLimMode', 'manual'); % prevent the axes from resizing automatically
p = get(tObj, 'Extent'); %Get the outer position of the text
% now create a patch around the text object
pObj = patch([p(1) p(1) p(1)+p(3) p(1)+p(3)], [p(2) p(2)+p(4) p(2)+p(4) p(2)], 'r');
uistack(tObj, 'top'); % put the text object on top of the patch object
set(pObj , 'FaceAlpha', .2); % set the alpha of the patch face to .2
%Rotate the objects
set(tObj, 'Rotation', 20);
rotate(pObj, [0 0 1], 20);
I am afraid the only way you can do this is by not setting any color to your annotations, and then placing a patch in the background of each annotation. So something like this:
% Use completely transparent annotations
hA = annotation('textarrow', ..., 'TextBackgroundColor', 'none')
% Place a transparent patch exactly in the background of your annotation
hP = patch(X, Y, 'white', 'EdgeColor', 'none', 'FaceColor', 'white', ...
'alpha', 0.3)
% Ensure that your annotation is on top
uistack(hA, 'top')
But of course the big problem is to determine the correct coordinates of the patch (X and Y). Rotating is easy by simply multiplying your coordinates by a rotation matrix. However, finding the length and height of the patch and its central location is not that easy. You might be able to find some useful functions for this at Matlab central...