mola_metric_maps

Advanced metric map classes for LiDAR odometry and SLAM, built on the generic mrpt::maps::CMetricMap interface. All maps are serializable, visualizable, and integrate with the mp2p_icp registration library.

Map classes

Production-quality maps

Experimental / work-in-progress maps

Utility / internal classes

Build and install

Refer to the root MOLA repository.

License

Copyright (C) 2018-2026 Jose Luis Blanco jlblanco@ual.es, University of Almeria

This package is released under the GNU GPL v3 license as open source for research and evaluation purposes only. Commercial licenses available upon request, for this package alone or in combination with the complete SLAM system.

Changelog for package mola_metric_maps

3.1.1 (2026-08-10)

• mola_metric_maps: fix calloc arg order and nodiscard warnings on newer GCC.
• Give nn_search_cov2cov() a canonical pairing order. The parallel path merged per-thread correspondences in unspecified order, making ICP results non-deterministic run to run; now sorted by local_idx to match the sequential path.
• IncrementalPointCloud: rebuild the k-d tree on a global SE(3) re-map. changeCoordinatesReference() rewrote coordinates in place without resizing, so the k-d tree kept stale split planes and nearest-neighbor queries silently returned wrong results. Fixes #186.
• mola_metric_maps: depend on nanoflann_vendor instead of nanoflann, since the rosdep key otherwise resolves to the distro's older libnanoflann-dev.
• fix(mola_metric_maps): don't require nanoflann>=1.5.1 for KeyframePointCloudMap covariances. Ubuntu jammy's older nanoflann made every use of mola::KeyframePointCloudMap throw on Humble; now falls back to a plain kNN truncated at the same radius, verified numerically equivalent.
• Contributors: Jose Luis Blanco-Claraco

3.1.0 (2026-08-06)

• Merge pull request #187 from MOLAorg/feat/incremental-point-cloud-kdtree-bake Bake IncrementalPointCloud's k-d tree index (mm-ipc-bake-kdtree)

• address review comments

• Add k-d tree baking for IncrementalPointCloud + mm-ipc-bake-kdtree tool Serializes the incremental k-d tree index alongside an IncrementalPointCloud layer's points (TCreationOptions::serialize_kdtree), so it does not have to be rebuilt (an O(N log M) bulk build) on every load. Unlike KeyframePointCloudMap's baked static trees, nanoflann's incremental index had no save/load support at all; this depends on saveIndex()/loadIndex() added upstream (nanoflann >= 1.11.0, see the companion nanoflann PR), gated behind MOLA_METRIC_MAPS_HAS_INCREMENTAL_KDTREE_BAKE so older builds keep working with the option as a documented no-op. Serialization always writes/reads the compacted (tombstone-free) point order, so baking builds a throwaway index over that exact order rather than reusing the live index (whose slots may not match after tombstones/slot recycling). Adds the mm-ipc-bake-kdtree CLI tool (analogous to mm-kf-bake-kdtrees) and a shared mm_cli_utils.h generic layer-iteration helper for it. Unit tests cover: bake/load round-trip through memory and through a real temporary file, k-d tree parameters differing between bake and load time, clearing and re-inserting into a loaded (baked) map, further insertions/trims on a loaded map, and serialize_kdtree=false remaining a no-op -- all independent of whether this build's nanoflann actually supports baking.

• changelog

• chore: document and fix some multithreading issues

• Merge pull request #185 from MOLAorg/chore/remove-keyframe-map-capable Remove the KeyframeMapCapable interface

• docs: drop the KeyframeMapCapable references left behind

• chore: remove the KeyframeMapCapable interface This mixin was introduced to expose per-KF pose plumbing to mola_lidar_odometry's trajectory-rebake experiment, which corrected accumulated tilt by re-integrating the keyframe chain. That experiment is being removed: it was never wired in, and rotating map keyframes without transforming the trajectory consistently leaks vertical position. The interface had exactly one implementation and no callers, so it is removed along with the two methods that existed only for the rebake path, [oldestActiveKeyframeID()]{.title-ref} and [applyPivotTransform()]{.title-ref}. [keyframePoses()]{.title-ref} is kept, since the regroup tests already use it as ordinary map API, and the duplicate [cloneKFPoses()]{.title-ref} (whose only difference was not being the virtual one) is folded into it.

• Merge pull request #184 from MOLAorg/feat/incremental-pointcloud-map feat(metric_maps): add mola::IncrementalPointCloud (incremental k-d tree local map)

• docs: correct the trySetCreationOptions contract The k-d tree parameters used to require an empty map, with trySetCreationOptions() returning false rather than discarding points. It now compacts and rebuilds instead, so it always succeeds and keeps the map contents; only the previously returned point indices are invalidated. The TCreationOptions docs still described the old behaviour.

• style: apply clang-format-14

• feat(metric_maps): degrade gracefully on distros with an old nanoflann The incremental k-d tree index needs nanoflann >= 1.10.0.

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