Migration tool for pbstream files

The pbstream serialization format for 3D has changed to include additional data (histograms) in each submap. Code to load old data by migrating on-the-fly will be removed soon. Once this happened, users who wish to migrate old pbstream files can use a migration tool.

The tool is shipped as part of Cartographer’s pbstream tool (source) and once built can be invoked as follows::

cartographer_pbstream migrate old.pbstream new.pbstream

The tool assumes 3D data in the old submap format as input and converts it to the currently used format version.

Migrating pre-1.0 pbstream files

With the update of the pbstream serialization format as discussed in RFC-0021, previously serialized pbstream files are not loadable in Cartographer 1.0 anymore.

In order to enable users to reuse previously generated pbstream files, migration using an older version of the migration tool is necessary. The current tool does not support this migration anymore. Please use the version at Git SHA 6c889490e245cc5d9da15023249c6fc7119def3f.