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susana
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Update scatter plot with different colors set by the user

Asked by susana
on 15 Sep 2017
Latest activity Commented on by susana
on 20 Sep 2017
Hello,
I have a Gui that is plotting a scatter data into an axes. I want to be able to update the scatter with different colors by a depth condition (minfm, maxfm). The code is as follows:
scatter=findobj(eixo.Children,'type','Scatter');
minfm=[1000;2500];
maxfm=[2000;4000];
color={'blue';'green'};
[l,~]=size(scatter.YData);
[lin,~]=size(color);
V=repmat({'black'},1,l);
for i=1:lin
for j=1:l
if Y(j)>minfm(i) && Y(j)<maxfm(i)
V{:,j}=color{i,1};
end
end
end
set(scatter,'MarkerFaceColor',V{:});
I get the following error:
Error using matlab.graphics.chart.primitive.Scatter/set
There is no green property on the Scatter class.
The vector is ok, but I always get this error and it only plots everything in green

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1 Answer

Answer by Walter Roberson
on 15 Sep 2017
Edited by Walter Roberson
on 15 Sep 2017
 Accepted Answer

scatter=findobj(eixo.Children,'type','Scatter');
minfm=[1000;2500];
maxfm=[2000;4000];
color = [0 0 1; 0 1 0]; %{'blue';'green'};
[l,~]=size(scatter.YData);
[lin,~]=size(color);
V=repmat([0 0 0],l,1); %{'black'}
for i=1:lin
for j=1:l
if Y(j)>minfm(i) && Y(j)<maxfm(i)
V(j,:)=color(i,:);
end
end
end
set(scatter,'MarkerFaceColor',V);
It looks to me as if you should be able to condense that quite a lot.
color = [0 0 0; 0 0 1; 0 1 0];
Vidx = 1 + (Y > minfm(1) & Y < maxfm(1)) * 1 + (Y > minfm(2) & Y < maxfm(2)) * 2; %assume the ranges are mutually exclusive
V = color(Vidx(:), :);

  2 Comments

Hello,
I had try that solution already. I got the following error:
Error using matlab.graphics.chart.primitive.Scatter/set Error setting property 'MarkerFaceColor' of class 'Scatter': Color value must be a 3 element numeric vector
I've checked and the vector is ok (nx3 double)... I cannot condensate the code like that because I don't have fixed depth intervals. The user may add as many intervals as he wants.
I've solve the problem. If you want to specify multiple colors of your scatter plot it is not possible to just set 'MarkerFaceColor' to multiple different colors. For a single scatter plot with different colors for the markers the 'CData' property to a Nx3 matrix of RGB values (not color strings) needs to be set. Plus, the previous MarkerFaceColor and MarkerEdgeColor needs to be set 'flat' prior to set the scatter with the new color property.. So it will be something like this: set(scatter,'MarkerFaceColor','flat') set(scatter,'MarkerEdgeColor','flat') set(scatter,'CData',new_vector)

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