OpenLayers OSMWaySnap

OpenLayers extension for drawing line string with snapping to way elements from OpenStreetMap using OverpassAPI.

Instructions

npm install ol-osmwaysnap

Create an instance of class OSMWaySnap and add it to map. (Default snapping to OSM roads)

import VectorLayer from 'ol/layer/Vector';
import VectorSource from 'ol/source/Vector';
import { OSMWaySnap } from 'ol-osmwaysnap';

const targetLayer = new VectorLayer<VectorSource<Feature<LineString>>>({
  source: new VectorSource<Feature<LineString>>()
});
map.addLayer(targetLayer);

// Default: Snap to roads (OSM highway)
const interaction = new OSMWaySnap({
  source: targetLayer.getSource(),
  maximumResolution: 5,
  fetchBufferSize: 250,
  overpassEndpointURL: 'https://...' // Choose one instance from https://wiki.openstreetmap.org/wiki/Overpass_API#Public_Overpass_API_instances
});
map.addInteraction(interaction);

Or specify a custom OverpassQL for different way elements, for example to railways.

// Snap to railways
const interaction = new OSMWaySnap({
  source: targetLayer.getSource(),
  maximumResolution: 5,
  fetchBufferSize: 250,
  overpassQuery: '(way["railway"];>;);',
  overpassEndpointURL: 'https://...' // Choose one instance from https://wiki.openstreetmap.org/wiki/Overpass_API#Public_Overpass_API_instances
});
map.addInteraction(interaction);

Or use a custom vector source (not OSM) for snapping.

const interaction = new OSMWaySnap({
  source: targetLayer.getSource(),
  waySource: someVectorSource,
  maximumResolution: 5,
  fetchBufferSize: 250
});
map.addInteraction(interaction);

Constructor Options

• autoFocus?: boolean - True to automatically fit map view to next candidantes. (default: true)
• focusPadding?: number - Used with autoFocus, specify number to add padding to view fitting. (default: 50 !PROJECTION SENSITIVE!)
• sketchStyle?: StyleLike - Style of sketch features (default is predefined, overwrite if necessary)
• source: VectorSource<Feature<LineString>> - Target source of edition
• waySource?: VectorSource<Feature<LineString>> - Ways source for snapping (default to a new instance of OSMOverpassWaySource)
• createAndAddWayLayer?: boolean - Create a new way layer from way source (if provided) and add to map (default: true)
• wrapX?: boolean - WrapX
• allowCreate?: boolean - Whether to allow creating a new feature (default: true)
• allowEdit?: boolean - Whether allow geometry edition to start when clicking on an existing feature, the option can be later configured in allowEdit property of OSMWaySnap class (default: true)

If waySource is not provided, OSMOverpass will be used as source for snapping, so the constructor options for OSMWaySnap will be extended to include thoses options from OSMOverpassSourceBase.

Events

All event objects dispatched have property feature being the active feature of the interaction.

Event types:

• waysnapstart: when the interaction starts on a feature whether creation or edition.
• waysnapstartcreate: when the interaction has created a new feature.
• waysnapstartedit: when the interaction has started edition an existing feature.
• waysnapupdate: when the interaction has updated the active feature.
• waysnapend: when interaction has finished.

Examples

Examples in HTML using CDN

Using as module

import { Map, View } from 'ol';
import TileLayer from 'ol/layer/Tile';
import VectorLayer from 'ol/layer/Vector';
import OSM from 'ol/source/OSM';
import VectorSource from 'ol/source/Vector';
import Feature from 'ol/Feature';
import LineString from 'ol/geom/LineString'; 
import OSMWaySnap from 'ol-osmwaysnap';

const basemap = new TileLayer({ source: new OSM() });
const targetLayer = new VectorLayer<VectorSource<Feature<LineString>>>({
  source: new VectorSource()
});

const view = new View({
  center: [11018989, 2130015],
  zoom: 16
});
const map = new Map({
  target: 'map',
  layers: [basemap, targetLayer],
  view
});

const interaction = new OSMWaySnap({
  source: targetLayer.getSource(),
  maximumResolution: 5,
  fetchBufferSize: 250,
  overpassEndpointURL: 'https://...' // Choose one instance from https://wiki.openstreetmap.org/wiki/Overpass_API#Public_Overpass_API_instances
});
map.addInteraction(interaction);

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