FlatGeobuf (FGB)

FlatGeobuf is a binary vector data format based on FlatBuffers, which appeared in 2018 as "a shapefile for the cloud". Features are laid out in the file sequentially, with a spatial index written alongside, so the fragment you need is read directly, without parsing the whole file.

The main feature is working over HTTP range requests: you can put the file in object storage or on static hosting and read from the browser only the features that fall into the current screen. You don't have to stand up a geoserver for the sake of one layer.

All the selected layers are merged into a single .fgb, and every feature keeps a _layer attribute with the name of its source layer — it takes the export apart again into roads, buildings, water and greenery. OpenStreetMap attributes are preserved, coordinates are WGS84 (EPSG:4326), and the spatial index is written automatically.

Compared to GeoJSON the file is noticeably smaller and reads faster; compared to a shapefile there are no limits on field name length, encoding or size. There is one price to pay: you cannot look at such a file in a text editor.