layer:
  id: "boundary"
  description: |
    Contains [administrative boundaries](http://wiki.openstreetmap.org/wiki/Tag:boundary%3Dadministrative)
    (no maritime boundaries yet).
    Until z7 Natural Earth data is used which switches to OSM boundaries after z8.
  buffer_size: 4
  fields:
    admin_level: |
        OSM [admin_level](http://wiki.openstreetmap.org/wiki/Tag:boundary%3Dadministrative#admin_level)
        indicating the level of importance of this boundary.
        At low zoom levels the Natural Earth boundaries are mapped to the equivalent admin levels.
  datasource:
    query: (SELECT * FROM layer_boundary(!bbox!, z(!scale_denominator!))) AS t
schema:
  - ./boundary.sql
datasources:
  - type: imposm3
    mapping_file: ./mapping.yaml