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Elger Jonker edited this page Feb 15, 2017 · 1 revision

Welcome to the faalkaart/website wiki!

This renders the data from the database to a human-understandable format.

Mapping Information / GeoJSON

Please go through the resources in order to understand how to add districts, points and lines of interest to the map.

  1. Learn about how maps work: https://www.youtube.com/watch?v=2lR7s1Y6Zig
  2. What projections Open Street Maps uses: http://openstreetmapdata.com/info/projections
  3. Fail map / Open Street Maps uses GeoJson, described at: http://geojson.org

A harder challenge is to get data from a country in GeoJSON. Some countries publish a (large) map for the use with mapping tools (GIS Tools). A free mapping tool to work with this is QGIS, available at qgis.org

Any map you'll download will probably contain way too much details. Next steps describe the process to convert a large map to something smaller, so it uses (way) less data:

  1. Download a map, for example administrative regions of the Netherlands: https://www.pdok.nl/nl/producten/pdok-downloads/basis-registratie-kadaster/bestuurlijke-grenzen-actueel
  2. Open the map in QGIS, it will look heavily distorted as an unfamiliar (but correct) projection is used.
  3. It's possible to change the projection on the fly. Look for the tiny globe icon and choose something like "Mercator (EPSG 3857)"
  4. After you're happy with the projection and "the world makes sense again" remove complexities from the map.
  5. Reducing complexities reduces the file size from 8 megabyte to hundreds of kiloytes.
  6. Vector > Geometry Tools > Simplify Geometries, enter 500.0000 or something like that. Let the algorithm do it's job.
  7. Now right click on the simplified layer and export it. You can export it to GeoJSON that the fail map software understands. The projection is called "WGS84 (EPSG 4326)".
  8. Import the data into the database, a procedure not yet described.

Wish: OSM only solution.

OSM uses the administrative regions etc, and it's possible to determine addresses and such.

There are API's that let one search through the data and export the right things. Yet this was not implemented yet. This would be the easiest way to have updated mapping data from all around the world that requires a lesser amount of special steps. (the data is always there, from everywhere =)

There are converters that reduce OSM to GeoJSON (but don't reduce complexity afaik):

  1. https://tyrasd.github.io/osmtogeojson/

Other things

Additionally there is an awesome world map in GeoJSON, available here: https://github.com/datasets/geo-countries/blob/master/data/countries.geojson

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