This work is dependant on support for 2d and 2dsphere indexes on time-series collections. This ticket includes support for $geoIntersects, $geoWithin, and the $geoNear stage. Operators $near and $nearSphere and $geoNear currently produces errors when used in any aggregation so we don't need to support them here.
We'd need to change the parsing behavior to specifically allow $geoNear on a time series view. Currently $geoNear must be with a $match at the beginning of the pipeline and is also specifically banned on views (although there is no custom error message).
$geoNear needs custom pushdown. We'd also need a way to divide the stage in twain should the stage be on metadata but a metric be on a data value.
We'd also need to ensure that the meta predicate pushdown code written for
SERVER-53484 handles $geoIntersecs and $geoWithin predicates. Tests can be added to pipeline/document_source_internal_unpack_bucket_test/
We should think about the ramifications of this patch. Currently optimization is entirely optional. How should we organize the code for a mandatory rewrite?
SERVER-55239 Support 2dsphere index on time-series collection metadata fields