Configuration

Config inheritance

Share common settings across several maps with a base config. Each map can override the settings that differ.

What you see: three basemaps, the home button, the legend position and the share link all come from the organisation base file. This map itself only declares one layer, a view and its own accent colour.

The map config

Short, because it inherits:

extends.map0.json

{
  "$schema": "https://map0.net/schema/v1.json",
  "version": 1,
  "extends": "/configs/_base.map0.json",
  "meta": { "title": "Noise map, inherits the organisation defaults" },
  "map": { "center": [16.3725, 48.2083], "zoom": 13 },
  "theme": { "primary": "#b45309" },
  "layers": [
    {
      "id": "areas",
      "type": "geojson",
      "title": "Study areas",
      "data": "/data/demo-areas.geojson",
      "style": {
        "fill-color": "#b45309",
        "fill-opacity": 0.28,
        "line-color": "#b45309",
        "line-width": 2
      },
      "popup": { "title": "{{name}}" }
    }
  ]
}

The shared base

Maintained once, centrally, and reused by every map in the organisation:

_base.map0.json

{
  "basemaps": [
    {
      "id": "grau",
      "title": "Grey",
      "type": "raster",
      "url": "https://mapsneu.wien.gv.at/basemap/bmapgrau/normal/google3857/{z}/{y}/{x}.png",
      "attribution": "© basemap.at",
      "default": true
    },
    {
      "id": "bmapv",
      "title": "basemap.at",
      "type": "style",
      "url": "https://mapsneu.wien.gv.at/basemapv/bmapv/3857/resources/styles/root.json"
    },
    {
      "id": "ortho",
      "title": "Aerial",
      "type": "raster",
      "url": "https://mapsneu.wien.gv.at/basemap/bmaporthofoto30cm/normal/google3857/{z}/{y}/{x}.jpeg",
      "maxZoom": 19,
      "attribution": "© basemap.at"
    }
  ],
  "theme": { "primary": "#0e7490", "radius": "md" },
  "controls": { "legend": { "position": "bottom-right" }, "home": true },
  "permalink": true
}

Merge rules

Objects are merged recursively: a child’s theme.primary overrides the base value while the base’s theme.radius is retained
Arrays are replaced in full, preserving the order specified in the child config
Chains up to three levels deep (global → department → map), with cycle detection
Relative extends URLs resolve against the config file that declares them

Replacing arrays. To change an inherited layer list, provide the complete list in the child config. This explicitly defines which layers appear and in what order. Settings omitted from the child continue to come from the base.