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Conversion of Degrees to Normalised units

Hi,

I would be very thankful for an answer if there is any convenient way to convert stimuli positions from degrees of visual angle to Normalised units.

I am using the degrees of visual angle to set up the positions of my stimuli as this is the most convenient way to do so (I need them to be distributed in a circular manner on equidistant positions). However, I would like to send to the data file (using ThisExp.addData) not the degrees but the normalised units as this would be much more practical for subsequent analysis.

Best regards
Mike

There are some conversion functions between units here:

https://www.psychopy.org/api/tools/monitorunittools.html#module-psychopy.tools.monitorunittools

but none for directly converting to normalised units, perhaps because in practice they aren’t generally that useful. Are you sure from an analysis point of view that you want to move from a single number that unambiguously specifies a position on a circle of fixed radius, to a pair of cartesian values (whether normalised or in any other cartesian system)?

If you do really want to do this, it would probably be better to use height units rather than norm, as the latter distorts circles to ellipses.

Hi Michael,

Thank you for your answer. I will go to deg2pix than. In fact, I am designing an eye-tracking experiment and the tracker gives the position of gaze also in normalised units where the monitor has a dimension from [0,0] to [1,1]. I was, therefore, searching for the metric that would be closest to this representation. But pixels would also do.

Best regards
Mike