qsm_summary() does not accept filtered data without the main stem.

[aidanmorales]

If the main stem is missing from the QSM (e.g. from using prune_qsm(invert = TRUE) or dplyr::filter()), the following error is thrown:

Error in if (DBHCyl >= 1.37) { : missing value where TRUE/FALSE needed

This behavior is not intended and needs to be fixed in a future update. An NA value for dbh, and a message to the user will be added.

If a connected structure is provided (e.g. a branch), the function should be dynamic enough to consider it a "tree", but reject disconnected structures (e.g. multiple branches).

[aidanmorales]

From the changelog:

qsm_summary() is now dynamic and can accept filtered data. If the filtered QSM data is a connected structure (e.g. a branch), the lowest order will be considered as the main stem, and the standard summary will be calculated. If the QSM data is disconnected (e.g. several pruned branches), only total volume and surface area will be calculated, and the user will be notified. Additionally, DBH calculations are also dynamic. If the main stem of a tree or branch is shorter than DBH (1.37 m), DBH will be NA, and the user will be notified. Previously, trying to summarize any filtered data would throw an error (issue #7).