Setting time in PIVlab command line example

[Penelope Knox]

Hello

In the example code Example_PIVlab_commandline.mlx, how did you establish the time step/frame rate between each analysed frame?

[thielickeoptolution]

You have to apply the conversion from px/imagepair --> m/s yourself at the very end of the script. Multiply your x and y with real_distance/pixel_distance ; and your u and v with real_distance/pixel_distance/timestep .

[John Shaw]

It appears that PIVlab has native units of millimeters and milliseconds (in GUI and command line). Is this true? If I am using landsat imagery separated by year, I want to multiply x and y by 30,000 mm/pixel and u and v with 30,000 mm/pixel/(3.15E10 ms).

Am I thinking about that right?

[William]

Hi, PIVlab is using SI units only in the code. The numbers you can manually enter into the reference distance field in the GUI is divided by 1000 to yield meters.

You woul need to enter a year in milliseconds in the GUI, but you need to enter the year in seconds in command line related stuff. The same is true for the length units (mm in the GUI and m in the command line.