Enable querying relation members by role

clarisma / geodesk

Fast and storage-efficient spatial database engine for OpenStreetMap data

https://docs.geodesk.com/java

Apache License 2.0

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Enable querying relation members by role #3

Open clarisma opened 2 years ago

clarisma commented 2 years ago

Support querying relation members by role, e.g.

relation.members("w[role=main_stream]")

This would be more efficient than checking member.role() programmatically, since we wouldn't need to de-reference features whose role doesn't match (possibly avoiding a tile download).

Need to address the following:

What happens when "role" is used in queries over sets that aren't relation members? Ignore "role"? Return nothing?

clarisma commented 1 year ago

role is not an officially supported OSM tag, but nonetheless there are features with a role tag.
using [role=x] for member queries precludes using role as a tag in general queries
Perhaps treat role as a CSS-like class? w.main_stream instead of w[role=main_stream]? This syntax would make it impossible to match partial strings or regex (as well as negate matches), but are there really use cases for those?
To match multiple roles: w.outer, w.inner instead of w[role=outer,inner]