MATLAB: Plotting a line through 2 points

interpolation

Hello,

I have a file with a difference in acceleration between 2 conditions, filename is 'ad'. I need to draw a line through 25% and 75% of the max of this data and then find the x-position where this line intercepts the x-axis.

As an illustration, this is what I want to do: http://tinypic.com/r/rab7te/5

Any help is appreciated, thanks.

Best Answer

Use the line() function. Just figure out the two endpoints, which shouldn't be very hard at all. Use "hold on" before you call line() so that you don't blow away the curve.

Related Solutions

MATLAB: How to draw a line bewteen two points using the exponential distribution

expdf fits a pdf to a distribution of points... it doesn't define the pdf at given x-coordinates. So in your code, you're fitting an exponential distribution to uniform data (the x-coordinates), which is of course not what you want.

If you just want a curve following the approximate shape of a negative exponential, then I recommend defining the curve explicitly, rather than messing with fitting:

x1 = -25;   % Coordinates of first bar
y1 = 0.015;
x2 = 0;     % Coordinates of red line start
y2 = 0.0025;
dy = y1 - y2;
dx = x2 - x1;
k = 1;
f = @(x) dy.*exp(-k*(x + dx)) + y2;
x = linspace(x1, x2, 50);
y = f(x);

You can adjust the k parameter to get a steeper or shallower drop-off in the curve.

MATLAB: Drawing line from center to other three points

Yes. You can use line() or plot();

line([xCenter, xVector(1)], [yCenter, yVector(1)], 'Color', 'r', 'LineWidth', 2);  
line([xCenter, xVector(2)], [yCenter, yVector(2)], 'Color', 'r', 'LineWidth', 2);  
line([xCenter, xVector(3)], [yCenter, yVector(3)], 'Color', 'r', 'LineWidth', 2);

Best Answer

Related Solutions

MATLAB: How to draw a line bewteen two points using the exponential distribution

MATLAB: Drawing line from center to other three points

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