guidance-geojson

guidance-geojson
----------------
Project for generating guidance-specific labelling/route styling data for GL from Mapbox Directions responses.

``js
var guidanceGeoJSON = require('guidance-geojson');

var geojson = guidanceGeoJSON(directionsResponse);
// console.log(geojson);
`

$3

Guidance GeoJSON provides a FeatureCollection with the following feature types:

- segments are LineString features that together make up the route to be traveled.
- labels are Point features for maneuver points where the user needs to make a turn.
- waypoints are Point features for starting, final, or intermediate destinations.

Each feature has the following properties exposed for styling in Mapbox Studio:

property | segment | label | waypoint
--- | --- | --- | ---
type | segment | label | waypoint
bearing | null | 0-360 | null
modifier | null | TBD | null
name | null | Name of next road | Name of waypoint road
waypoint | null | null | "first"|"last"|null

@TODO: provide example Guidance GeoJSON file for styling in studio as a static route.

$3

Once you have created your map style you can have it dynamically style a route. To do so, however, you will need to use the stylePrep() and styleRoute() methods to omit the layers in your style when loading your map and then apply those styles to your dynamic guidance GeoJSON once loaded:

`js
var guidanceGeoJSON = require('guidance-geojson');
var mapboxgl = require('mapbox-gl');
var directionsResponse = require('./stored-directions-response.json');

var map = new mapboxgl.Map({
container: 'map',
// Defers showing all layers from style beginning with route
style: guidanceGeoJSON.stylePrep(style, 'route')
});

map.on('style.load', function () {
var route = guidanceGeoJSON(directionsResponse);
// Restores style layers and adjusts dynamically to style route GeoJSON
guidanceGeoJSON.styleRoute(mapboxgl, map, route);
});
``