How to draw a line between two points on a graph?

Hello everyone,

Is there any way to draw a line on a plot in the center as shown in the figure. And I need the length of the line to be same as for the first plot and to the others. Please kindly help me. Thanks in advance.

My code:

Z = readtable('Atq100_2.xlsx') ;

data = table2array(Z) ;

N = size(data,2);

Nsp = N/2;

ttlc = {'x=10mm', 'x=250mm', 'x=500mm', 'x=1000mm', 'x=1500mm'};

xofst = [10 250 500 1000 1500];

figure

ylim([-1 1]*200)

xlim([0 1600])

hold on

for k = 1:Nsp

col = [2 1]+2*(k-1);

famp = 5; % Amplification Factor

datacol1 = data(:,col(1))*famp+xofst(k);

hp(k) = plot(datacol1, data(:,col(2)), 'LineWidth',2);

% plot(data(:,col(1))+xofst(k), data(:,col(2)), 'LineWidth',2)

% minx = min(data(:,col(1))+xofst(k));

% maxx = max(data(:,col(1))+xofst(k));

minx = min(datacol1);

maxx = max(datacol1);

plot([1;1]*[minx maxx], ([1;1]*ylim).', ':k', 'LineWidth',1) % Plot Vertical 'scale' Lines

% plot([1;1]*[minx], ([1;1]*ylim).', ':k', 'LineWidth',1) % Plot Vertical 'scale' Lines

end

hold off

hl = legend([hp], ttlc, 'Location','northeastoutside');

WIth regards,

Answer 1

[Star Strider]

I recognise that code!

I added this plot call to the others in the loop:

plot([minx maxx], [0 0], '-k', 'LineWidth',1) % Plot Horizontal 'zero' Lines

It plots a horizontal line at 0 for each section defined by the ‘scale’ lines.

Z = readtable('https://www.mathworks.com/matlabcentral/answers/uploaded_files/748504/Atq100_2.xlsx') ;
data = table2array(Z) ; 
N = size(data,2);
Nsp = N/2;
ttlc = {'x=10mm', 'x=250mm', 'x=500mm', 'x=1000mm', 'x=1500mm'};
xofst = [10 250 500 1000 1500];
figure
ylim([-1 1]*200)
xlim([0 1600])
hold on
for k = 1:Nsp
    col = [2 1]+2*(k-1);
    famp = 5;                                                               % Amplification Factor
    datacol1 = data(:,col(1))*famp+xofst(k);
    hp(k) = plot(datacol1, data(:,col(2)), 'LineWidth',2);
    %     plot(data(:,col(1))+xofst(k), data(:,col(2)), 'LineWidth',2)
    %     minx = min(data(:,col(1))+xofst(k));
    %     maxx = max(data(:,col(1))+xofst(k));
    minx = min(datacol1);
    maxx = max(datacol1);
    plot([1;1]*[minx maxx], ([1;1]*ylim).', ':k', 'LineWidth',1)            % Plot Vertical 'scale' Lines
    %     plot([1;1]*[minx], ([1;1]*ylim).', ':k', 'LineWidth',1)            % Plot Vertical 'scale' Lines
    plot([minx maxx], [0 0], '-k', 'LineWidth',1)            % Plot Horizontal 'zero' Lines
end
hold off
hl = legend([hp], ttlc, 'Location','northeastoutside');

Experimenbt to get different results.

.

[Vishnuvardhan Naidu Tanga]

Hello @Star Strider

Once again hai and thank you for your quick response. But what I need is i need all the horizantal lines to be of equal length not just the max and min lengths. For example the length for all the lines has to be same as length of the line for the first plot.

[Star Strider]

Sure!

That simply requires a tweak in the code —

Z = readtable('https://www.mathworks.com/matlabcentral/answers/uploaded_files/748504/Atq100_2.xlsx') ;
data = table2array(Z) ; 
N = size(data,2);
Nsp = N/2;
ttlc = {'x=10mm', 'x=250mm', 'x=500mm', 'x=1000mm', 'x=1500mm'};
xofst = [10 250 500 1000 1500];
figure
ylim([-1 1]*200)
xlim([0 1720])
hold on
for k = 1:Nsp
    col = [2 1]+2*(k-1);
    famp = 5;                                                               % Amplification Factor
    datacol1 = data(:,col(1))*famp+xofst(k);
    hp(k) = plot(datacol1, data(:,col(2)), 'LineWidth',2);
    %     plot(data(:,col(1))+xofst(k), data(:,col(2)), 'LineWidth',2)
    %     minx = min(data(:,col(1))+xofst(k));
    %     maxx = max(data(:,col(1))+xofst(k));
    minx(k) = min(datacol1);
    maxx(k) = max(datacol1);
    plot([1;1]*[minx(k) maxx(k)], ([1;1]*ylim).', ':k', 'LineWidth',1)            % Plot Vertical 'scale' Lines
    %     plot([1;1]*[minx], ([1;1]*ylim).', ':k', 'LineWidth',1)            % Plot Vertical 'scale' Lines
    plot([minx(1) maxx(1)]+minx(k)*(k>1), [0 0], '-k', 'LineWidth',1)            % Plot Horizontal 'zero' Lines
Line_Coordinates = [minx(1) maxx(1)]+minx(k)*(k>1)              % Check Line Length (Delete)
LineLength = diff(Line_Coordinates)                             % Check Line Length (Delete)
end

Line_Coordinates = 1×2

10.0446 210.3789

LineLength = 200.3344

Line_Coordinates = 1×2

260.1239 460.4582

LineLength = 200.3344

Line_Coordinates = 1×2

510.0542 710.3886

LineLength = 200.3344

Line_Coordinates = 1×2

1.0e+03 * 1.0105 1.2109

LineLength = 200.3344

Line_Coordinates = 1×2

1.0e+03 * 1.5105 1.7109

LineLength = 200.3344

hold off
hl = legend([hp], ttlc, 'Location','northeastoutside');

The horizontal line lengths are all the same, even though they might not appear that way in the plot with the original xlim values, so I changed xlim to allow the complete ‘zero line’ to show for all the curves.. I added ‘Line_Coordinates’ and ‘LineLength’ to demonstrate their equality. (Delete them later.)

.

[Vishnuvardhan Naidu Tanga]

Thank you once again @Star Strider. One small change i request you is that the line should not start from zero. It should start from point 10. And similarly all the other should start at the dotted offset line. Can you please change correspondingly. Have a nice weekend and thank you for your help.

[Star Strider]

As always, my pleasure!

Thank you! You, too!

.

[Vishnuvardhan Naidu Tanga]

Thank you once again @Star Strider. One small change i request you is that the line should not start from zero. It should start from point 10. And similarly all the other should start at the dotted offset line. Can you please change correspondingly. Have a nice weekend and thank you for your help.

[Star Strider]

As always, my pleasure!

Please check the ‘LineCoordinates’ results. They show where the ‘zero lines’ begin and end. It can be difficult to see in the plot, however for the first line:

Line_Coordinates = 1×2

10.0446 210.3789

So it works correctly.

.

[Vishnuvardhan Naidu Tanga]

I am sorry. For the first plot it is fine but for the other plots it starts at 10 points after. For example for the second plot it should start at 250 but starts at 260. Simillarly same for the others. I have attached the data here.

[Star Strider]

That is easily corrected —

Z = readtable('https://www.mathworks.com/matlabcentral/answers/uploaded_files/748504/Atq100_2.xlsx') ;
data = table2array(Z) ; 
N = size(data,2);
Nsp = N/2;
ttlc = {'x=10mm', 'x=250mm', 'x=500mm', 'x=1000mm', 'x=1500mm'};
xofst = [10 250 500 1000 1500];
figure
ylim([-1 1]*200)
xlim([0 1720])
hold on
for k = 1:Nsp
    col = [2 1]+2*(k-1);
    famp = 5;                                                               % Amplification Factor
    datacol1 = data(:,col(1))*famp+xofst(k);
    hp(k) = plot(datacol1, data(:,col(2)), 'LineWidth',2);
    %     plot(data(:,col(1))+xofst(k), data(:,col(2)), 'LineWidth',2)
    %     minx = min(data(:,col(1))+xofst(k));
    %     maxx = max(data(:,col(1))+xofst(k));
    minx(k) = min(datacol1);
    maxx(k) = max(datacol1);
    plot([1;1]*[minx(k) maxx(k)], ([1;1]*ylim).', ':k', 'LineWidth',1)            % Plot Vertical 'scale' Lines
    %     plot([1;1]*[minx], ([1;1]*ylim).', ':k', 'LineWidth',1)            % Plot Vertical 'scale' Lines
    plot([minx(1) maxx(1)]-minx(1)+minx(k), [0 0], '-k', 'LineWidth',1)            % Plot Horizontal 'zero' Lines
    Line_Coordinates = [minx(1) maxx(1)]-minx(1)+minx(k)            % Check Line Length (Delete)
    LineLength = diff(Line_Coordinates)                             % Check Line Length (Delete)
end

Line_Coordinates = 1×2

10.0446 210.3789

LineLength = 200.3344

Line_Coordinates = 1×2

250.0793 450.4137

LineLength = 200.3344

Line_Coordinates = 1×2

500.0097 700.3440

LineLength = 200.3344

Line_Coordinates = 1×2

1.0e+03 * 1.0005 1.2008

LineLength = 200.3344

Line_Coordinates = 1×2

1.0e+03 * 1.5005 1.7008

LineLength = 200.3344

hold off
hl = legend([hp], ttlc, 'Location','northeastoutside');

.

[Vishnuvardhan Naidu Tanga]

Thank you so much for the help @Star Strider. Have a nice weekend.

[Star Strider]

As always, my pleasure!

You too!

.

Answer 2

[Image Analyst]

You can use either plot(), which is very general, or line() which is more specialized for lines.