incf-nidash/nidm — pull request #149 by cmaumet (2014-09-15 08:56:55+00:00)
Title: Definition of "Map"

**Term**: `Map `
**Current definition**: "2D or 3D structured dataset."
**Original comment**: [link](https://docs.google.com/a/mrn.org/spreadsheets/d/16pC2cDsdxlzv2CzlNMtStqt5-xHwDEsU6MjZVxWhrE4/edit?disco=AAAAAGsYjiA)

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@khelm `20:24 9 Apr`
I would not refer to the dimension as that will be a separate attribute. How about "A matrix whose element values are statistic or model-parameter values."?

@gllmflndn `16:56 14 Apr`
I agree about dimension.
I think we should be even more generic by not refering to "matrix" (for surface-based data) nor describing what the values are ("statistic or model-parameters") as we've also got MaskMap, ReselsPerVoxelMap, etc. Maybe a simplified version of "Set of values corresponding to the discrete sampling from a function of some underlying support"?

@nicholsn `20:30 18 Apr`
I like Guillaume's definition, but what is meant by "some underlying support"?

@JessicaTurner `20:47 22 Apr`
Can we have a one or >3 dimensional map? I think it's worth being clear about how map is used in the ni-dm context, unless we think one-dimensional maps are likely to be used at some point.

@cmaumet `16:24 23 Apr`
If we want to stay generic and be able to cover the different types of analyses available in SPM (cf. examples at the end of [this doc](https://docs.google.com/document/d/1uIn2eqe9kpOOViT4zPrqBP239EBEuVOYGn8ys5MelCc/edit), then 'Map' can be of dimension 1, 2, 3 (not sure about >3).

@cmaumet `16:26 23 Apr`
+1 in favour of Guillaume's definition.