Improve Pairwise Dissolve: Avoid concatenating attributes for features that remain single-part

[Yannick-Atos]

Currently, when running Dissolve or Pairwise Dissolve with the single part option, statistics field's attribute values from all features that share the same dissolve field values are calculated or concatenated—even if those features remain separate geometries because of the single part constraint.

Before dissolve:

Before dissolveYou would expect that for single part features, only OID 2 and 4 (LINK_ID 1305630123 and 1305630124) are dissolved, and therefore only these two should have their LINK_IDs concatenated.

After the dissolve, however, the statistics fields are calculated independently of the spatial entity:

After dissolve

The dissolve leads to unexpected and sometimes incorrect attribute tables:

• Features that remain spatially distinct (single part enforced) end up with concatenated attributes from other features that were not dissolved with them.

• As a result, attribute values can be misleading and do not reflect the actual geometry or logical unit of the feature.

Expected/Proposed behavior:

• Attribute concatenation should only apply to features that are actually dissolved into a new geometry.

• Features that remain single-part should keep their original attribute values, rather than concatenating values from unrelated geometries.

Why this matters:

• Maintaining data integrity: users expect attributes of non-dissolved features to remain unchanged.

• Preventing unnecessary post-processing: currently, extra steps are required to clean up attributes that were concatenated although geometries were not merged.

• Improving consistency with user expectations: many users assume “single part” means attributes are preserved unless geometries are explicitly dissolved.

This change would make the Pairwise Dissolve tool more intuitive, reduce errors, and align the attribute output with the spatial result.