CGA FAQ: DST and GCD formats

Hello CGA subscribers!

Could anyone tell me, where I could get a specification for the DST or GCD file protocols?
Any pointer would be much appreciated.

Best regards
Kai Anding

Dear List members,

        Details of the DST and GCD formats are included in the documentation supplied
with the MLSviewer, a file viewer for DST/GCD files.  This program allows the
user to view the contents of any DST/GCD formatted file. It is available
(along with evaluation versions of all our software applications) from the
download page at our web site ( and via anonymous ftp.

        The various file specification details can be accessed from the MLSviewer by
selecting the option "CAMARC Help" from the help menu.

        A registered version of the MLSviewer is normally $295 US - however we are
currently offering free registrations upon request until the end of 1999.

Edmund Cramp
Motion Lab Systems, Inc.
4326 Pine Park Drive, Baton Rouge, LA  70809  USA
+1 225 928-4248 (voice, 2 lines), +1 225 928-0261 (fax)
web site <>

Hello, this is Dr. Cho in S-Korea.
I am tryng statistical comparison of Vicon gcd files of male and female.
But I have some trouble in understanding numeric columns under "ground reaction" and "Pelvic
center" (what does each column means ?)   You can refer to the Excel file attached to this

Any comment or explanantion about the above matter will be greatly appreciated !


Sang-Hyun Cho MD.,PhD.,Dip. Clin Gait Analysis
Rehabilitation Medicine Specialist, Assistant Professor
Dept. of Physical Therapy, College of Health Science
Y O N S E I   U N I V E R S I T Y
** home =
** Mobile phone = 011-366-8043
** Voice = +82-371-760-2491  FAX = +82-371-760-2496

Dear Dr. Cho,

The GRF data are simply the Fx, y, z; Mx, y, z

x is the anteroposterior, y is medio-lateral and z is vertical

The first three columns of the Pelvic data are x, y, z coordinates of
the center of the pelvis with respect to the lab origin (note in your
file, the subject is walking "backwards", i.e. from left to right, so
the x coordinate gradually decreases).

I confess I don't know what the the next three columns are. Perhaps
someone else can illuminate us?

By the way, I'll excuse your posting an attachment to the list just this
once - please don't do it again! :-)

Dr. Chris Kirtley MD PhD
Associate Professor
HomeCare Technologies for the 21st Century (Whitaker Foundation)
NIDRR Rehabilitation Engineering Research Center on TeleRehabilitation
Dept. of Biomedical Engineering, Pangborn 105B
Catholic University of America

Well if Chris doesn't know it might be worth posting this to everyone.

The .gcd files are arranged in columns the first column is the mean value
and th second column is the standard deviation. Thus the 12 columns for
Ground Reaction are
z(ave),Mz(sd). Simmilarly for the pelvic origin these are position

Having explained this I sould point out that all the Moment and Pelvic
Origin averages are meaningless as they are relative to the laboratory
co-ordinate system and thus highly dependent on exactly where the subject
was during the gait cycle in question. You could argue that the force data
is meaningful but remember that if the subjects were different weights then
this data is un-normalised and therefore most of the variability is due to
the different weights of the children and not to their gait patterns.

Richard Baker

Dear List members,

Anyone interesting in viewing the contains of Vicon GCD files is welcome to
access our web and ftp sites ( and
download our software for accessing GCD files.  The following programs (32-bit
95/98/NT versions) are available:

Opens and displays the contents of any DST formatted file (including GCD
files).  The evaluation version lacks the ability to print any hardcopy but
otherwise is fully functional so it's quite useful.  It also opens and
displays the contents of C3D files.

GCD Statistics Exporter
Opens very large numbers (like 1,000's) of GCD files and exports a single,
user selected, variable to an ASCII text file - designed to allow a researcher
to create ASCII text files for submission to the big stats packages like
Statistica or SAS etc.  Fully functional but unsupported.

DST/GCD file editor
Opens and edits any DST or GCD file - this is a utility that allows you to
view and change the contents of a GCD file in a graphical or numeric
environment.  Like all MLS products it includes full help files - of
particular interest is a full description of the various CAMARC GCD lexicons -
including the Vicon GCD file lexicon.  Fully functional but unsupported.

Edmund Cramp,
Motion Lab Systems, Inc.
4326 Pine Park Drive, Baton Rouge, LA?70809?USA
+1 225 928-4248 (voice, 2 lines), +1 225 928-0261 (fax)


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