[MINC-users] Dimension data type

[Jean-Philippe Coutu]

Dear MINC users,

In the minc header, how does the data type of the dimension matter?

For instance, one could start with a 2D slice with this for its yspace:

int yspace ;
yspace:length = 1 ;
yspace:varid = "MINC standard variable" ;
yspace:vartype = "dimension____" ;
yspace:version = "MINC Version    1.0" ;
yspace:comments = "Y increases from patient posterior to anterior" ;
yspace:spacing = "regular__" ;
yspace:alignment = "centre" ;
yspace:start = -4.1 ;
yspace:direction_cosines = 0., 1., 0. ;
yspace:units = "mm" ;
yspace:spacetype = "native____" ;
yspace:step = 0.1 ;

(both xspace and zspace are also int in this case, but with length >1)

Now if one attempts to replicate this slice in the yspace dimension with
this command:

mincconcat -verbose -concat_dimension yspace -filestarts -0.1,0,0.1
slice.mnc slice.mnc  slice.mnc out.mnc

The mincheader of out.mnc will now display this:

double yspace(yspace) ;
yspace:length = 3 ;
yspace:dimorder = "yspace" ;
yspace:varid = "MINC standard variable" ;
yspace:vartype = "dimension____" ;
yspace:version = "MINC Version    1.0" ;
yspace:comments = "Y increases from patient posterior to anterior" ;
yspace:alignment = "centre" ;
yspace:direction_cosines = 0., 1., 0. ;
yspace:units = "mm" ;
yspace:spacetype = "native____" ;
yspace:spacing = "regular__" ;
yspace:start = -4.2 ;
yspace:step = 0.0999999999999999 ;

So it went from int to double (both xspace and zspace remain int), and in
addition, something weird happened where yspace became yspace(yspace).

Now if one was to run something like mincreshape -normalize on either the
slice.mnc or out.mnc, all xspace, yspace and zspace will now become double
rather than int.

Is this important for any minc operation? Can it be 'normalized' back to
int somehow?

Thanks,
JP