OpenMapTiles is an extensible and open vector tile schema for a OpenStreetMap basemap. It is used to generate vector tiles for openmaptiles.org.

We encourage you to collaborate, reuse and adapt existing layers and add your own layers or use our approach for your own vector tile project.

• 🔗 Docs https://openmaptiles.org/docs
• 🔗 Schema: https://openmaptiles.org/schema
• 🔗 Production package: https://openmaptiles.com/
• 🔗 Openmaptiles Github: https://github.com/openmaptiles/openmaptiles

If you have created a own layer structure and think this can be useful for someone else, please make a Pull Request and share it with the rest of the world.

1. Download the openmaptiles main project.
2. Go into the openmaptiles directory
3. Add the layer to the openmaptiles.yaml [more](Add the layer to the Tileset).
4. Execute make commands:

make clean                  # Remove the build directory
make                        # Generate sql out of the layers
make import-osm             # Import OSM Data into the tables they are defined in mapping.yaml
make import-sql             # Import SQL functions from the <layer>.sql (park.sql)
make generate-tiles-pg      # Generate .mbtiles file

5. Start your Tileserver.

make start-tileserver

And go to localhost:8090 6. Optional for better developing, start a Maputnik server to check the layers data in the Inspect mode.

make start-maputnik

And go to localhost:8088

TODO: Explain how to connect maputnik with the local tiles. Is this needed?

TODO: A good sample project is needed

To explain the structure, the sample park is used.
The following layers are childs of the folder park:

Optional:

Start point / General definition file.

Sturture and fields of the file:

⚠️

All columns of the SELECT-Satement needs to be defined in the fields section. Only the geometry columns don't need to be defined, because of geometry_field.

If a layer SQL files contains %%FIELD_MAPPING: class%%, generate-sql script will replace it

TODO: is generate-sql the correct one?

SELECT CASE
    %%FIELD_MAPPING: class%%
END, ...

into

SELECT CASE
    WHEN "subclass" IN ('school', 'kindergarten')
        OR "subclass" LIKE 'uni%' THEN 'school'
    WHEN ("subclass" = 'station' AND "mapping_key" = 'railway')
        OR "subclass" in ('halt','tram_stop','subway') THEN 'railway'
END, ...

Sample:

layer:    
  id: "park"    
  description: |    
      Custom description. The park layer contains parks from OpenStreetMap tagged with    [`boundary=national_park`](http://wiki.openstreetmap.org/wiki/Tag:boundary%3Dnational_park), ... 
  buffer_size: 4 fields:    
  class:
    description: Defines a subclass of a park
    values:
      school:
        # subclass IN ('school','kindergarten') OR subclass LIKE 'uni%'
        subclass: ['school','kindergarten','uni%']
      railway:
        # (subclass='station' AND mapping_key='railway')
        # OR subclass in ('halt','tram_stop','subway')
        - __AND__:
          subclass: 'station'
          mapping_key: 'railway'
        - subclass: ['halt', 'tram_stop', 'subway']
  datasource:    
    geometry_field: geometry    
    query: (SELECT geometry, class, name, name_en, name_de, rank FROM layer_park(!bbox!, z(!scale_denominator!))) AS t 
  schema:    
    - ./update_park_polygon.sql    
    - ./park.sql
  datasources:    
    - type: imposm3    
    mapping_file: ./mapping.yaml  

imposm3 mapping file to choose the OSM data you need.

TODO: When is mapping: and when type_mappings: needed

Sample: https://imposm.org/docs/imposm3/latest/mapping.html#example or:

tables:  
  # etldoc: imposm3 -> osm_park_polygon  
  park_polygon:  
    type: polygon  
    _resolve_wikidata: false  
    columns:  
    - name: osm_id  
      type: id  
    - name: geometry  
      type: geometry
    - name: name  
      key: name  
      type: string   
    - name: leisure  
      key: leisure  
      type: string  
    - name: boundary  
      key: boundary  
      type: string  
    - name: area  
      type: area  
    mapping:  
      leisure:  
      - nature_reserve  
      boundary:  
      - national_park  
      - protected_area

Creates SQL functions to get the correct data from the database while tile-generation

CREATE OR REPLACE FUNCTION layer_hydranten(bbox geometry, zoom_level int)
RETURNS TABLE(geometry geometry, type text, class text) AS $$
    SELECT geometry, type, CAST('fire_hydrant' as text)
    FROM osm_hydranten_point
    WHERE geometry && bbox;
$$ LANGUAGE SQL IMMUTABLE;

TODO: When is used IMMUTABLE and when others like STABLE PARALLEL SAFE;

TODO: Explain most used SQL functions like st_centroid, ST_NPoints, ST_Area, ST_Dump, ST_Union, ST_MakeValid, ST_Simplify, ...

TODO: Explain why it is useful to have a extra sql file

In the openmaptiles project you need to change the file openmaptiles.yaml. Add the new layer to layers:

tileset:
  layers:
    - layers/park/park.yaml

TODO: How is this working Maybe with make generate-devdoc?

ERROR: relation "osm_YOURTABLE_polygon" does not exist.

Script: make TODO: Check

Solution: You need to check if you have set the table correct in your .sql file and in your mapping.yaml file. Don't forget that in the mapping.yaml you need to set the table without osm_.

ERROR: cannot change return type of existing function

Script: make import-sql

Solution: You need to recreate your DB with destroy-db or drop the function

[Makefile:257: build/openmaptiles.tm2source/data.yml] Error 1

Script: make

Solution: Some of the layers / schemas are not valid. Comment out the layers in openmaptiles.yaml and find out which one throws the error.

File "/usr/src/app/import-wikidata", line 222, in find_tables for table_name, table_def in mapping['tables'].items(): KeyError: 'tables'

Script: make import-wikidata

Solution: In the .yaml file the mapping_file value is not correct or the mapping.yaml has not the attribute tables