## Presets

iD uses a simple presets system based on [JSON](http://en.wikipedia.org/wiki/JSON)
preset definitions and simple structure.

## Individual Presets

Specific presets are located under `data/presets/presets`. They're organized in a
directory hierarchy based on OSM key/value pairs. For example, the preset that matches
the tag `leisure=park` is in the file `data/presets/presets/leisure/park.json`.

## Preset Format

A basic preset is of the form:

```javascript
{
    "name": "park",
    // the geometry types for which this preset is valid.
    // options are point, area, line, and vertex.
    // vertexes are points that are parts of lines, like the nodes
    // in a road
    // lines are unclosed ways, and areas are closed ways
    "geometry": [
        "point", "area"
    ],
    // terms are synonyms for the preset - these are added to fuel
    // the search functionality. searching for 'woodland' will bring
    // up this 'park' preset
    "terms": [
        "esplanade",
        "village green",
        "woodland"
    ],
    // tags that are added to the feature when selecting the preset,
    // and also used to match the preset against existing features.
    // You can use the value "*" to match any value.
    "tags": {
        "leisure": "park"
    },
    // the icon in iD which represents this feature
    "icon": "park",
    // An array of field names. See the fields documentation for details of what's valid here.
    "fields": [
        "address"
    ]
}
```

## Fields

Fields are, like presets, defined in JSON structures. A typical field is

```js
{
    "key": "access",
    "type": "combo"
}
```

In which `type` is the fields's type. Valid field types are

* textarea
* radio
* combo
* check
* address
* defaultcheck - a checkbox that can be yes, no, or null - not filled

The `key` property names the OSM key that the field will edit. Alternatively, for
compound fields like `address`, you can specify an array of keys in the `keys`
property.

Each field definition lives in a separate file in `data/presets/fields`. The field
name (used in the preset `fields` property) is the name of the file (minus the `.json`
extension).

## Building

To build presets, all you need to to is run `make`.

This command will take care of running the build script, which packages all presets
together with imagery data, and deprecated or discarded tags into one file, `data/data.js`,
which is included in the packaged iD.js file.