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Importing already-detected fixations

Apr 18, 2012 at 2:19 PM


I was wondering if it might be possible to import fixations that have already been detected with another software. I use a software written by a colleague to clean up the raw data and to detect fixations (the algorithm for fixation detection is based on Nystrom & Holmqvist, 2010). I would like to be able to import our fixations into OGAMA and carry out further analyses on those.




Apr 18, 2012 at 6:38 PM

Hi there,

You should try the fixation import assistant in the fixations module (buttons at the end of the toolbar). This will allow you to use most of the modules (which are based on fixation tables) even if there is no raw data in the database. I would also like to invite You to persuade your collegue to provide the algorithm as a code plugin for ogama using the open sources, so that you can (in a next version) choose which fixation detection algorithm Ogama should use... that would help other users as well!

Regards, Adrian

Apr 19, 2012 at 10:53 AM


Thanks for the speedy reply! I told my colleague about your proposal, and you should have received an email from him by now.

Regarding my original question: I tried using the fixation import assistant, without importing the raw data. I follow the steps, but after I specify the subject name, I get the following error message: Subject not present. A subject with this name is not present in the experiments database. Please change the subject name. And then I'm stuck there. I tried the following two things:

1. In my fixation data file (a .csv file), I added a column with the subject's code (since the data came from the same participant, the code was the same on all rows). Then I tried importing the file again, but got a message saying: Unhandled exception has occured in your application. If you click Continue, the application will ignore this error and attempt to continue. If you click Quit, the application will close immediately. The given key was not present in the dictionary. If I click Continue and try to import, I get another error message saying The given key was not present in the dictionary.

2. I opened the New Database Module, to figure out if I could add subjects there, but I can't seem to figure out how (only adding Custom parameters seems to be possible), and I couldn't find any information on that in the documentation. (Te import assistant for this module seems to import the raw data, not just participant information).

Thank you.


P.S. I forgot to mention it in my first post: I played only a little with Ogama, but I find it quite impressive. It seems easy to use and flexible. I'm really glad you took the time to build it.

May 14, 2012 at 7:14 PM

First, thanks for giving me the collegues contact, I will try to adapt ogama, so that it is easier to add a new fixation detection algorithm like a plugin.

Regarding the fixation import: I agree, that it would be a nice to have option to import fixations completely without the raw data (including subject information) but the fixation import is not able to do this at the moment, thats why you get the ugly error messages. So

1) my first workaround would be to import your unfiltered raw data with the raw data import assistant of the database module (which calculates fixations with the built in filter and generates subjects and trials) and afterwards overwrite the calculated fixations with the fixation import assistant with your own calculated fixational data. This might be not that easy but should work...

2) send me one of your fixation import csv and I will see whether I may adapt the fixation import to created subject and trial database entries if they are not there already.

Hope it helps, sorry for the late reply, Adrian

Jul 9, 2012 at 3:17 PM

Thank you for your response and sorry about not replying sooner. In response to your suggestions:

1) I tried that - with some variations - but I still get the Unhandled exception... error.

2) You should receive an email from me with that file today.

In addition to this, I have another question: Where does OGAMA get the TrialEvents from? I'm asking because every time I import my data, that section stays empty. Does the raw data file need to have a specific structure?

Thank you.

Apr 7, 2014 at 8:58 AM
Hi Ioana,
somehow late reply, this was not easy to fix... thanks for your data, I was now able to Import it.
I reworked the Fixation Import, so that it is more clear on how to Import fixations.
The method 1) will be your choice, because ogama Needs to have correct Trial starting times and they never are exactly the starting time of a Fixation, so we cannot just add Trials and subjects from a Fixation table, if you doesn´t mind that Point, you can use the Fixation file and treat it as raw data for the step one of method 1) (but that is not recommended).
I tried to implement method 2) but for the mentioned reasons of uncorrect Timing i decided to skip this approach.
There was also a bug in the Fixation Import preventing it from beeing successful, which I fix with Version 4.5. You are then able to overwrite the fixations calculated by ogama using the fixations Import assistant, but be sure to Import raw data first, to have Stimuli, subjects, Trials and Timings already in the database.