feaure request: marine human footprint

[AMBarbosa]

Hi!

A god complement to the footprint() map would be a version for marine regions, such as
https://www.researchgate.net/publication/5574961_A_Global_Map_of_Human_Impact_on_Marine_Ecosystems/figures

Cheers!

[AMBarbosa]

Raster data available here: https://oceanhealthindex.org/resources/data/cumulative-human-impacts/