On 07/01/2019 18:43, Adriaan van Os wrote:

At zoom level 7, I get a strange line on the base-map here: <https://tile.gbif.org/3575/omt/7/61/92@4x.png?style=gbif-middle>

This is an effect of the process used to generate the polar projections, which used a pre-tiled source of data for the oceans from zoom 7 and up.  The rectangles are different sizes, so there are gaps between them when their corners are reprojected into EPSG:3575. I intend to reprocess the polar base maps, but since they're not often used on the GBIF.org website it's not a high priority. Cheers, Matt ⇒ https://github.com/gbif/gbif-basemaps/issues/10