Find the x values of where my plot intersects a y='some constant' line

Hi,

I have time series data of tidal stream velocity and want to know at which times the velocity equals a specific value.

See the plot (I'm focusing on the top right-hand subplot) ... The orange line is my tidal stream velocity over a period of 24 hours. And I want to extract at what times it becomes equal to a velocity of 1m/s (represented on the graph by the dashed black line).

I only have a velocity data point every hour, so the plot is formed from 24 data points - one every hour.

Perhaps I have to interpolate between the data points? I'm not really sure. Any help would be greatly appreciated.

Thank you!

Answer 1

[KSSV]

YOu may use interX a function from file exchange.

https://in.mathworks.com/matlabcentral/fileexchange/22441-curve-intersections?focused=5165138&tab=functionMathWorks

[Emma Whettall]

Exactly what I needed. Thank you!