Trajan is only used at most a couple times in the notebooks, however it is included in our feedstock recipe causing anyone installing Parcels to also pull in trajan (and dependencies).

Trajan dependencies:
https://github.com/conda-forge/trajan-feedstock/blob/main/recipe/meta.yaml#L19-L38

Of particular note are cartopy, pyproj and roaring landmask (the last of which is a dataset provides a global landmask).

We can still have trajan in our development environment if we want to still use it in tutorials.