# Layers

Layers are a sub setting of a locale. Each layer object has a set of parameters which depend on the type of layer, whether the layer is interactive or editable and how the data should be styled in the map window.&#x20;

Valid layers for the current locale will be listed in the Layers control of the client application.

The drawing order of layers is dependent on the order of the layer keys in the layers object. **Layers added last to the list will be drawn on top.**

```javascript
"layers": {
  "base": {
    "group": "Base maps",
    "display": true,
    "name": "Mapbox Baselayer",
    "attribution": {
      "© Mapbox" : "https://www.mapbox.com/about/maps",
      "© OpenStreetMap": "http://www.openstreetmap.org/copyright"
    },
    "format": "tiles",
    "URI": "https://api.mapbox.com/styles/v1/dbauszus/ciozrimi3002bdsm8bjtn2v1y/tiles/256/{z}/{x}/{y}?&provider=MAPBOX"
  }
}
```

A layer will be listed by it's name. If no name has been set for a layer it will be listed under it's key in the locales object.

`"display": true`

If the display key is set to true the layer will be displayed by default. Otherwise the layer display can be toggled through the client interface.

`"hidden": true`

A layer can be hidden from the layers list. It is still possible to select locations from hidden layers and aggregate scores from hidden layers can be used in lookup fields. Hidden layers can be used as scratch layers to store aggregate locations created from running [**filter outputs**](infoj/infoj/filter).

`"group": "Base maps"`

Groups will be created for every unique group name found in any of the layer definitions. Layers will be nested in their respective group in the Layers control.

`"meta": "Satellite Imagery layer provided by HERE."`

The meta value will be displayed as text directly under the layer header in the Layer control of the client application.

```
"attribution": {
  "© Mapbox" : "https://www.mapbox.com/about/maps",
  "© OpenStreetMap": "http://www.openstreetmap.org/copyright"
}
```

The attribution object can hold multiple key/value pairs. The key being the text displayed in the lower right corner of the map control when the corresponding layer is visible and the value being the link for the attribution text.

`"format": "tiles"`

The format value is mandatory for valid layers. The layer type defines the additional parameter a layer may use. The additional parameter are described in the individual format sections.
