Discover Available Output Spaces

Discovers the available output spaces (MNI152NLin2009cAsym, fsaverage, etc.) for a derivative dataset. Parses BIDS _space- entity from filenames.

Usage

on_spaces(derivative, refresh = FALSE, client = NULL)

Arguments

derivative: A single-row tibble from on_derivatives() output. Must contain columns: dataset_id, pipeline, and source.
refresh: If TRUE, bypass cache and fetch fresh data. Default is FALSE to use cached results.
client: An openneuro_client object for API calls (embedded sources). If NULL (default), creates a default client.

Value

A character vector of space names, sorted alphabetically. Common spaces include:

Volumetric: MNI152NLin2009cAsym, MNI152NLin6Asym, T1w
Surface: fsaverage, fsaverage5, fsaverage6, fsnative

Returns character(0) with a warning if no spaces are found.

Details

Space Discovery

This function samples derivative files and extracts the _space-<label> entity from BIDS-formatted filenames. It does NOT infer T1w from files without a space entity (per BIDS convention, native space files may omit the space entity).

Source Handling

embedded: Uses the OpenNeuro API to list files in the derivatives/{pipeline}/ directory.
openneuro-derivatives: Uses AWS CLI to list files from the s3://openneuro-derivatives/ bucket.

Caching

Results are cached per-session to minimize API/S3 calls. Use refresh = TRUE to bypass the cache.

Examples

if (FALSE) { # \dontrun{
# First, get available derivatives for a dataset
derivs <- on_derivatives("ds000102")
print(derivs)

# Then get spaces for the first derivative
spaces <- on_spaces(derivs[1, ])
print(spaces)
# Example output: c("MNI152NLin2009cAsym", "fsaverage")

# Force refresh of cached spaces
spaces <- on_spaces(derivs[1, ], refresh = TRUE)
} # }