Eye Movement dataset questions!!!

I have following questions about the eye-tracking dataset. You answers will be greatly appreciated. Thank you. 

1- According to the readme file, the samples related to the first frame are starting from row 271, the eye-tracker's rate is 240 samples/second and the display rate is 31.185, so we should have 7.96 samples in each frame. With a simple calculation we can find the right frame that each sample is mapped to. However, some of the samples are lost, so in such a case how each eye-tracking sample (each row) is mapped to a frame? For example, what is the corresponding frame to the row 1000 in CZ_beverly03 dataset? 

2- Why coordinates are in decimal points?  What exactly the x and y coordinates mean? 

3- What is the resolution (accuracy) of the eye tracker?  For some good hardware they report 0.05 degree. How does the resolution affect the accuracy of the coordinates reported?

4- How many eyes are tracked, one or two?  Some hardware track only one eye. If two eyes are tracked, do they still report a single coordinate?

Thank you very much. I appreciate your cooperation. 

Kind regards

Ayub Bokani

Hi, I have almost the same problems.

Regarding above numbers, however, I am not agree with Ayub. There are 260 trash data and the first 3 rows give information regardless of fixations/saccade. So, the first frame has to start at row 264.

Also the display rate is 240/31.185 = 7.696 samples per frame

Thanks

Shortly, I need eye positions (from all participants) for a certain frame. Does anybody have any idea?