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What sensor coordinate system do Net Station and GeoSource 3.1 Research use?

Net Station uses a Cartesian coordinate system with X, Y, and Z dimensions to specify sensor positions in 3D space on the scalp surface.  In Net Station, this information is stored within the package contents of the MFF in the .xml file format. In GeoSource 3.1 Research, this information is stored in the .sfp file format

In the Cartesian coordinate system, the X axis runs left (negative) to right (positive); the Y axis runs posterior (negative) to anterior (positive); and the Z axis runs inferior (negative) to superior (positive). 

The reference electrode (Cz) is fixed at point (0, 0, Z), where Z is the positive height of Cz. The nasion is fixed at (0, Y, Z).  Since both the nasion and Cz are always fixed at X=0, they are assumed to be in the same Y plane. 

The origin is the center of the head, defined as the center of a sphere fit to fiducial points above the plane made up of the Left Preauricular Point (LPA), the Right Preauricular Point (RPA), and the nasion.  

Within both Net Station and GeoSource 3.1 Research, there is the option to use an average sensor position file, which is the default, or you can determine the exact sensor positions for each individual subject after the Net has been applied using the Geodesic Photogrammetry System (GPS 3.1) or the handheld GeoScan device.. 

Additional Info

  • Product Type: GeoSource and GPS
  • Information Type: Implementation Theory
Last modified on Thursday, 01 June 2017 16:35

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