Dear Darren,
>What is the order of coordinates in the XYZ matrix. It is not strictly
>sorted on any dimension that I can work out, and the variables reference by
>XYZ (i.e., XA or BETA also don't seem sorted in any particular way.
During the analysis SPM appends new locations of activations to XYZ as it
goes along. SPM96 analyses the data in chunks of small cubes of 8 x 8 x 8
voxels. Therefore, you won't find any consistent order in XYZ, XA, SPMF and
SPMt.mat. However, it is easy to sort XYZ and still not loose the reference
to the other matrices.
[y, i] = sort(XYZ(1,:)'); %Sort according to X coordinate, i contains the
new order of columns
XYZ(:,i) %Show XYZ sorted according to X
SPMt(1,i) %Sort the Z values of the first contrast
accordingly
-Christian
Dr Christian Büchel
Functional Imaging Laboratory
Wellcome Department of Cognitive Neurology
12 Queen Square
London WC1N 3BG, UK
Tel.:+44-171-833-7483
Fax.: +44-171-813-1420
email: [log in to unmask]
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