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Dimension variables

To represent the full set of attributes associated with a MINC dimension object, MINC 2.0 defines a ``dimension variable'', which is a variable with the same name as the corresponding dimension object. In MINC 2.0 these variables, like all other variables, are implemented as HDF5 ``datasets''.

MINC dimensions may have either regular or irregular spacing. Regularly-sampled dimensions are sampled at a constant interval, while irregularly-sampled dimensions are sampled at arbitrary positions along the axis.

Because regular dimensions are sampled at a constant interval, they are fully defined by their origin and step size. Therefore, the dimension variable for a regular dimension contains no meaningful data.

For an irregular dimension, the value of the dimension variable must be a vector with a length equal to the number of sampled points along the dimension. The value of the vector at a given index gives the value of the dimension at that sample point.

Robert VINCENT 2005-05-10