How to delete the ellipse of the previous state

I want to implement an input UE ID (edit1) will display an ellipse on axes.

But I want to have only one ellipse on axes.

For example: when I enter UE ID 5 and press pushbutton, and then enter UE ID 6 and press pushbutton, axes only show the ellipse of UE ID 6.

How can I modify it?

function pushbutton2_Callback(hObject, eventdata, handles)

[UELocation] = textread('observe/mdUELocationforGUI2.txt');
InputUEID = get(handles.edit1,'String');
InputUEID = str2double(InputUEID);
InputUEID3 = InputUEID+1;

[Pairlink] = textread('observe/mdPairlinkforGUI2.txt');
Node_ID = Pairlink(InputUEID3,4); %NodeID
Node_ID2 = Node_ID+1;

[UEBeamAngle] = textread('observe/mdUEHBeamAngleforGUI2.txt');
angles_Panel_0 = UEBeamAngle;
[NodeBeam] = textread('observe/mdNodeBeamforGUI2.txt');
Node_beamnumber = NodeBeam(1,3);


[NodeBeamAngle] = textread('observe/mdNodeBeamHAngleGUI2.txt');
    angles = NodeBeamAngle + 60; 

axes(handles.axes1)
hold on
xUECenter=UELocation(InputUEID3,2);
yUECenter=UELocation(InputUEID3,3);
[Nodelocation] = textread('observe/mdNodeLocationXY_axisforGUI2.txt');
ROIX = Nodelocation(1,5);
ROIY = Nodelocation(1,6);
axis([0 ROIX 0 ROIY])

a = 25*ROIX/1000;  %The length and width of the ellipse
b = 25*ROIX/1000;
r = a;
LineSpec='b';
plot_ellipse(a,b,r,xUECenter,yUECenter,angles_Panel_0,LineSpec)

xNodeCenter=Nodelocation(Node_ID2,2);
yNodeCenter=Nodelocation(Node_ID2,3);

r =  a;
LineSpec='k';
plot_ellipse(a,b,r,xNodeCenter,yNodeCenter,angles,LineSpec)

axis equal


function plot_ellipse(a,b,r,xNodeCenter,yNodeCenter,angles,LineSpec) % Draw ellipse function
%write documentation here explaing inputs and usage
hEllipse = imellipse(gca,[-a, -b, 2*a, 2*b]); 
xy = hEllipse.getVertices();
delete(hEllipse)
x = xy(:,1);
y = xy(:,2);
xy = [x y];
for k = 1 : length(angles)
    theta = angles(k);
    rotationArray = [cosd(theta) sind(theta); -sind(theta) cosd(theta)];
    rotated_xy = xy * rotationArray;
    xCenter = xNodeCenter + (r - 0.25) * cosd(theta);
    yCenter = yNodeCenter + (r - 0.25) * sind(theta);
    x = rotated_xy(:,1) + xCenter;
    y = rotated_xy(:,2) + yCenter;
    plot(x, y, LineSpec);
    if k == 1
        grid on;
        hold on;
    end
end

Answer 1

[Image Analyst]

Before you call plot(), call this function:

ClearLinesFromAxes(gca);

Here is the function:

%=====================================================================
% Erases all lines from the image axes "h". 
function ClearLinesFromAxes(h)
axesHandlesToChildObjects = findobj(h, 'Type', 'line');
if ~isempty(axesHandlesToChildObjects)
	delete(axesHandlesToChildObjects);
end
return; % from ClearLinesFromAxes

Answer 2

[Voss]

One way might be to turn hold off before plotting your ellipse(s). If you change this:

axes(handles.axes1)
hold on

to this:

axes(handles.axes1)
hold off

Does that work?