85 lines
2.9 KiB
Markdown
85 lines
2.9 KiB
Markdown
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# Tile Generation
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To display the collected data we generate vector tiles which can be rendered by
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different map renderers, such as
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[maplibre-gl-js](https://github.com/MapLibre/maplibre-gl-js) or
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[QGIS](https://www.qgis.org/en/site/).
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The whole process requires a dockerized setup. Of course you can try to install
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and run the tools without docker, but that is probably going to be very
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complicated, and we're not documenting it here.
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## Data sources
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There are two main sources of data. Both feed into a PostgreSQL database into
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separate tables, such that they can be joined for processing.
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### Application data
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The **API** imports tracks separately and stores the imported data into the
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`overtaking_event` table. This is already part of the application and does not
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need configuration, apart from specifying the correct `postgres.url` in the API
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config.
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### Importing OpenStreetMap data
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This is the road information imported from OpenStreetMap itself. Download the
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area(s) you would like to import from
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[GeoFabrik](https://download.geofabrik.de). Then import the files like this:
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```bash
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osm2pgsql --create --hstore --style api/roads_import.lua -O flex \
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-H localhost -d obs -U obs -W \
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path/to/downloaded/myarea-latest.osm.pbf
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```
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You might need to adjust the host, database and username (`-H`, `-d`, `-U`) to
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your setup, and also provide the correct password when queried. This process
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should take a few seconds to minutes, depending on the area size. You can run
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the process multiple times, with the same or different area files, to import or
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update the data. You can also truncate the `road` table before importing if you
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want to remove outdated road information.
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## Configure
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Edit the file `tile-generator/.env` and adjust the following variables:
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* `PGDATABASE, PGUSER, ...` if you have different PostgreSQL credentials
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* `BBOX`, a bounding box for the area you want to generate (keep it small). Use
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[this tool](https://boundingbox.klokantech.com/) to draw an area on a map.
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## Generate SQL functions
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The [OpenMapTiles](https://openmaptiles.org/) project is used to generate the
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vector tiles. For this, a lot of logic is generated and imported into the
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PostgreSQL database in the form of user functions. To generate and import these, run::
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```bash
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cd tile-generator/
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make clean
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make
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make import-sql
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```
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## Generate `.mbtiles` file
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This file contains all the vector tiles for the selected area and zoom levels,
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and different layers of information (according to the layer descriptions in
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`tile-generator/layers/` and `tile-generator/openmaptiles.yaml`). It is
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generated like this:
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```bash
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make generate-tiles-pg
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```
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## Publish vector tiles
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The tool [tileserver-gl](http://tileserver.org/) is used to publish the vector
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tiles separately through HTTP. The tileserver runs inside docker, so all you need to do for a development setup is start it:
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```
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docker compose up -d tileserver
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```
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It is now available at [http://localhost:3002/](http://localhost:3002/).
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